Science is the best way to dig out the truth of the natural world, but that doesn’t prevent many people from denying truths that are inconvenient or contrary to their preconceptions or faith.

ENLARGE

U.S. 30, east of Blair, Neb. June, 2011, Iowa DOT

The stunning floods, tornadoes, droughts and heat waves in 2011 caused more Americans to accept global warming — even if climate whizzes are chary of attributing individual weather events to the warming trend.

In the last month, denial of global warming has subsided in the wake of a string of floods, droughts and heat waves, culminating in the “summer in March,” 2012. Although Americans’ attitudes toward warming ebb and flow, on April 17, a Yale University poll reported that 69 percent think global warming is affecting the weather in the United States.

In the same month, however, a Discovery Channel series called “Frozen Planet” attracted ire when scientists noted that it documented massive melting at the poles, but ignored the “why?” question. Scientists have said for decades that polar warming would be an early sign of global warming.

In the recent past, this phenomenon of “denialism” has also appeared in doubts about issues that have long been settled in the scientific community, such as whether:

An April conference at the University of Wisconsin-Madison delved into the origin and development of denialism. Is a refusal to face facts growing more common? Are there better ways to explain how the world works?

Denial in the brain

Scientists, by training, are professional skeptics, but if after decades of debate 97 percent of them accept the link between greenhouse gases and global warming, why are so many unconvinced? “The theory is that if we tell people what we know, they will change,” says Arthur Lupia, a professor of political science at the University of Michigan, but that ignores how people really listen and make decisions.

Speaking to a high-level gathering of science journalists in Madison, Lupia said the problem does not reside with the audience. “The problem is us. Our expectations aren’t consistent with how humans react to information, what they will listen to, or what they will remember. People don’t pay attention, or they don’t remember what we said or what we intend them to remember.”

To change an opinion, you must first attract and then hold the audience’s attention, but attention wanders all the time. No matter how important you think your message is, Lupia says, “Biology does not change its rules … about when people will think about things that challenge them. … If I am saying something abstract, that does not connect to your core aspirations,” you may be more interested in counting tiles on the ceiling.

Can you hear me now?

To communicate with a general audience, Lupia says, “You have to make it close, concrete, immediate. I understand the joy of telling the whole story about climate, but there are some audiences that can’t handle it; in their reality, it’s not the most immediate thing. They might be more receptive if you make the conversation about pollution, energy security or energy costs.”

Information is filtered by attention and ideology, Lupia concludes. “Learning is always an away game. All the real action occurs in the audience’s heads,” he says.

Reasoning: Logical or “motivated”?

Ideally, science adheres to logical reasoning: the conclusion must be true if the premises are true.

But psychologists say it’s common to see “motivated reasoning,” the tendency to fit new information into existing attitudes.

Making a judgment or decision can often involve a “fundamental tension between believing what you want and believing what you have to believe based on the information in front of you,” says Peter Ditto, professor of psychology and social behavior at the University of California-Irvine.

“There is overwhelming evidence” that hopes, fears and social connections affect our judgments, Ditto adds, “but it’s not just that we believe whatever we want. I want to be taller, but I don’t believe that because the data won’t let me.”

Since processing information and making judgments have major emotional components, the standards for evidence are skewed in favor of reinforcing our preconceptions. We are more skeptical about ideas that are new, or that conflict with our thoughts and opinions, Ditto contends.

Over the course of evolution, bad events — but not beneficial ones — forced our ancestors to focus on whether to fight or flee. “People are the same way about information,” says Ditto.

The social element in motivated reasoning surfaced in a 1950s experiment, when six people convinced a seventh, the only real subject, that two lines were equally long. One line was clearly shorter than the other, Ditto says, “But six of them are confederates, and a substantial number of [subjects] go with the obviously wrong answer. That’s the power of having other people who believe as you do. It’s much easier to believe something that does not comport with reality if a whole bunch of others” hold the same erroneous belief.

History of denialism

Although denial of global warming and the erroneous link between vaccines and autism both originated in the 1990s, the organized rejection of evolution dates to the 1920s, when some American Christian fundamentalists promoted creationism — a Biblical explanation for the diversity of life on Earth.

In a 2009 survey, 87 percent of scientists, but only 32 percent of all Americans, agreed that organisms have evolved over time through natural processes. Thirty-one percent of Americans thought humans and other living things “have existed in the present form since the beginning of time.”

Scientists and other Americans certainly have a different understanding of how organisms change through time!

Scientist data and general public data from Pew Research Center for the People & the Press surveys, May-June 2009. For question wording, see survey toplines. Numbers may not sum to 100 due to rounding. Reprinted from Pew Research Center’s Forum on Religion & Public Life.

Much of the attention to the issue comes from battles over teaching of evolution or creationism in public schools, but there is “a lot of misunderstanding,” about the anti-evolution movement in the United States, says Ronald Numbers, a professor of the history of science at the University of Wisconsin-Madison, and longtime student of the movement.

Although creationism is commonly considered a backlash against science, “Virtually nobody in the movement [in the 1920s] thought of themselves as anti-scientific,” Numbers says. “They were denying the scientific status of evolution.”

The dictionary defines science as “organized, certain knowledge about nature, and they said, ‘Nothing is certain about evolution, nobody has seen it.’”

During the 1970s, primarily in response to court decisions, creationism morphed into “creation science” or “scientific creationism,” Numbers says. “The anti-evolutionists realized that evolution had a great deal of scientific support … so their approach was that they, too, were scientific.”

Unlike most anti-evolutionists in the 1920s, the new creationists used a literal interpretation of the Bible to date creation to less than 10,000 years ago. But this created a problem, Numbers says, since according to the Bible, on the sixth day, “God created the animals and Adam named them all.”

No way Adam could rattle off the more than 1 million names of the modern species so quickly, but Numbers notes that the Bible refers to “kinds,” not “species.” If those “kinds” — created in Eden and saved on Noah’s ark — were equivalent to taxonomic families, they could have evolved into the profusion modern species.

“So creationists can accept evolution within the family, and all the evidence for speciation is welcome, because in only about 4,300 years since the flood, they have to have evolution of all the species,” says Numbers. “It’s evolution in fast-forward,” but only among closely related species.”

Even if “kind” equals family, anti-evolutionists exempt humans from this reasoning, allowing them to reject human descent from apes — our fellow hominids.

“It’s strange, I know,” says Numbers. “They are anti-evolution, but most of the evidence evolutionists use against them, they are happy to embrace! One thing that has not been true for 50 years, but lingers in the popular mind, is that creationists deny all forms of evolution.”

The manual of denialism?

Evolutionary biologists regard evolution through natural selection as the organizing principle of biology. Yet for 30 or 40 years, surveys have shown a substantial fraction of Americans, even a majority, who do not “believe in” evolution, Sean Carroll, vice-president for science education at the Howard Hughes Medical Institute, told the denial conference.

Carroll, who like many biologists is aghast at the effort to squeeze evolution into a biblical straitjacket, says, “The denial of evolution was my introduction to denialism.”

ENLARGE

American Museum of National History

In 1954, children got a “Polio Pioneer” card, and a piece of candy after getting a jab of polio vaccine.

Typically, biologists have approached the evolution debate by amassing evidence, but “it’s never been about the data,” maintains Carroll, who is also a professor of genetics at the University of Wisconsin-Madison. “And if it’s not about the data, what are we talking about?”

An earlier example of denialism occurred in the 1950s, after Jonas Salk developed the polio vaccine, a breakthrough that halted a dreaded, paralyzing disease.

Many chiropractors, Carroll found, opposed vaccines since they negated the central premise of chiropractic — that all disease results from misalignment of the vertebrae. “It shocked me. They actively opposed, disputed the efficacy of the polio vaccine. The opposed the March of Dimes, and federal and state efforts to get everybody vaccinated.”

Five hallmarks of denialism

The opposition continued — even after the polio epidemic tapered off as a result of the mass vaccination that started in 1955, says Carroll. And he identifies the tactics used then as a “playbook” of science denial that is echoed in more recent struggles over evolution, vaccines and global warming:

We just don’t agree!

Add it up, and the theme is this: The science must not be allowed to endanger a key philosophy, Carroll says.

But the cost of denialism is high, Carroll maintains. “It’s difficult, as an evolutionary biologist, to realize that half the county is deaf to anything you have to say, especially if the story you have to tell is about a magnificent achievement, understanding the complex relationship of living things on the planet, the deep history of our species.”

To reach young people, Howard Hughes has begun producing and giving away a series of videos on evolution called The making of the fittest.

Go to links for videos

Howard Hughes Medical Institute

To bring science to the masses, Hughes has produced videos on evolution; this one describes how cold-water fish evolved “anti-freeze” genes.

The idea is to engage in storytelling — to help people understand and remember facts by putting them into a narrative framework, Carroll says. As a professor, he’s seen the power of a story. “When I got lost, off-topic, and students see me years later, they say they still remember some of those stories, and I know they don’t remember any of the genetics. Stories count.”

Time (dis)honored tactics

Naomi Oreskes, a professor of history and science studies at the University of California at San Diego, has written about the “merchants of doubt.”

The message, she says, is simple: The facts are not all in. We need to hold judgment until the scientists agree.

This kind of corrosive doubt — in the face of scientific certainty — is “very depressing” if you “believe that knowledge is power,” Oreskes says. “Knowledge is not powerful enough — an ideology is more powerful still. It’s about ideas, not facts.”

During the last half-century, she says, “Political powers are willing to attack rational truths, and those who deliver them.”

There is also money at stake in many of the issues, especially in the case of climate change, which threatens the fossil-fuel industry.

Car exhaust from eutrophication&hypoxia; smoky butt from Raul Lieberwirth

What do these have in common? Many companies in the oil and tobacco industries have sown seeds of doubt about the long-term effects of their products.

The model for such campaigns, Oreskes said, came from the tobacco industry in the 1960s. Facing growing evidence linking their profitable product to lung cancer, the industry settled on a strategy of promoting “Questions, manifested in a memorable maxim: “Doubt is our product.”

And for decades, doubt helped big tobacco deride and deny a tidal wave of evidence that cigarettes cause lung and heart disease.

December, 2011, Pew Research Center for the People & the Press.

After the crazy weather of the past year, pollsters have seen a bump in the number of Americans seeing “solid evidence” for global warming.

The same strategy, Oreskes says, was adapted to undermine “nuclear winter” (the discovery that huge clouds of ash and dust released during nuclear war could freeze and starve the planet), the dangers of the insecticide DDT, acid rain caused by power-plant pollution, the ozone hole, and global warming.

The tactics were to “challenge the evidence, claim the science is not settled, cherry-pick the data, to demand balance from journalists and threaten to sue if they don’t,” says Oreskes.

Changing the climate change story

The basic physics of global warming have been known for 100 years, Oreskes said. Scientists started exploring the subject with early computerized climate models in the 1980s.

In 1992, Oreskes said, the first President George Bush, “Called for concrete action to protect the planet. We had political leadership that committed us to doing something, yet we never did take the concrete steps that Bush called for. It’s a story about political challenges, selling uncertainty, about science in the age of denial.”

The doubters, funded by the oil industry, included some prominent Cold-War physicists who had been advocates for Ronald Reagan’s anti-missile defense system. “They said the science was unsettled, that it would be premature to act,” says Oreskes, who was intrigued to find that one of those physicists, Frederick Seitz, had been a consultant to the R.J. Reynolds tobacco company.

In 1998, Seitz organized a petition against the Kyoto Protocol, the first international agreement to control greenhouse gases.

Seitz and his fellow doubters, Oreskes says, “Found a new enemy: environmental extremism. You see anxiety about environmentalists as socialists, using climate change as a lever to effect social or economic change.”

What began with a handful of people with roots in the Cold War has since spread to “a range of free-market think tanks, including the Cato Institute and the American Enterprise Institute,” Oreskes says.

The arguments against the settled scientific debate over warming, she adds, “are not just different interpretation of the data; that’s a normal part of scientific life. This is not about normal scientific claims. These are the scientific equivalent of saying Belgium invaded Germany during World War I.”

Why deny? Because it works, Oreskes implies. Almost 25 years after the scorching summer of 1988 brought global warming into the public sphere, the United States has yet to get serious about controlling greenhouse gases.

“We ignore the facts of nature at our peril,” says Oreskes. “Ignoring them is not going to make them go away.”

On March 10, atmospheric chemist “Sherry” Rowland of the University of California-Irvine died in the company of his son and his wife of almost 60 years. Rowland became prominent in the 1970s after warning that common chemicals would destroy ozone 10 kilometers above Earth, exposing life to a shower of harmful radiation.

While exploring how chlorofluorocarbons (CFCs) degrade after being released into the atmosphere, Rowland and graduate student Mario Molina realized the CFCs would float to the upper atmosphere, be cleaved by sunlight, and release chlorine that would destroy ozone through a chain reaction.

(Ozone contain three oxygen atoms; most oxygen molecules contain two oxygens.)

By intercepting cancer-causing UV radiation, ozone in the stratosphere allows life to exist on Earth. Significant damage to this ozone would cause an epidemic of human and animal cancer, and likely damage plants as well.

This alarming prospect was not popular in industries that relied on CFCs, but it sparked a long and largely successful effort to restrict and then ban production of the chemicals.

And although Rowland never retreated from his findings, his calm, charismatic personality helped his cause. Ralph Cicerone, now the president of the National Academy of Sciences, recalls collaborating with Rowland on CFCs. “We talked on the phone nearly every day. I considered Sherry to be my best friend, and over time I learned that many people considered him to be their best friend, too. In the midst of the debates over CFCs, he never exaggerated the dangers, always cited the science, and treated other people with dignity and respect.”

What must a scientist do?

According to the University of California-Irvine’s press service, Rowland knew his results mattered far beyond the lab: “Mario and I realized this was not just a scientific question, but a potentially grave environmental problem involving substantial depletion of the stratospheric ozone layer. Entire biological systems, including humans, would be at danger from ultraviolet rays.”

At the time, scientists were studying the health implications of ozone-bearing smog in the lower atmosphere, but few people knew or cared about “good” ozone in the stratosphere.

The sudden notoriety of CFCs had a certain irony: The chemicals were invented in the 1920s at General Motors, maker of Frigidaire brand refrigerators, as a stable, non-toxic alternative to the ammonia and explosive propane used in air-conditioning and refrigeration.

CFCs later were used to expand plastic foam, clean electronic parts, and propel paint and deodorant in the mushrooming aerosol-spray business.

Antarctic ozone hole, 2011

   

Video: NASA

Chlorine and bromine in the upper atmosphere cause rapid ozone destruction in the super-chilled polar winter. Although the ozone “hole” (blue) is declining with the phase-out of CFCs, it still recurs.

They publish lest we perish!

Rowland’s 1974 study¹ ignited a long squabble over CFC production. Aerosol Age, the spray-can industry’s trade journal, implied that Rowland was a member of the Soviet KGB who wanted to destroy capitalism!

CFCs remained a back-burner issue, however, until the British Antarctic Survey discovered an alarming absence of ozone in 1985. The “Antarctic ozone hole” gave the theoretical worry sudden significance, and as the industry gradually found substitutes for CFCs, the ozone hole stopped expanding.

Today, as we watch the faltering response to global warming, it’s comforting to recall that the ozone threat prompted prompt collective action: The Montreal Protocol, a treaty to restrict CFC production, became effective in 1989 and has since been tightened after further alarm over ozone destruction, and 196 nations — essentially all of them — have signed the original Protocol. Production of ozone-depleting substances has fallen by more than 95 percent.

“CFCs were extremely useful compounds and their use was pervasive,” says Rudy Baum, editor in chief of C&EN (Chemical and Engineering News). “Although manufacturers maintained that there would be dire consequences if the use of CFCs were restricted or banned, it became clear pretty quickly that alternatives could be found in most cases.”

And yet ozone is still a problem, as shown by a 40 percent drop in Arctic ozone in the winter of 2010-2011. Continuing destruction is blamed on the stability of CFCs and the fact that the replacements, while less damaging, still destroy ozone. “Ozone can be thought of as a patient in remission, but it’s too early to declare recovery,” said Susan Solomon of the University of Colorado.

Not bounded by the lab walls

Nonetheless, the Montreal protocols are considered an epochal case of planetary preventive medicine, and Rowland, Molina and Paul Crutzen, who also worked on CFCs, were awarded the 1995 Nobel Prize for Chemistry.

But for 10 or 15 years, Rowland had played the role of maverick — speaking outside the laboratory about the importance of what he had found inside it. It’s not a comfortable role for many scientists; many find it safer to stay in the lab and let others figure out what to do with their results.

Jonathan Fink, vice-president of research at Portland State University, says “The culture of science is pretty deep in terms of how we are trained. Most science grad students are taught to focus on being the best at something, rather than thinking about the application of what they do to society.”

All along, Rowland explained the science and gently reminded us of our stake in an intact ozone layer. He continued to study atmospheric chemistry, mentor younger scientists, and show by example how scientists could speak responsibly about what their results mean for the rest of us.

Somehow, Rowland managed to fight his battles without making enemies, at least outside the industries that had inadvertently begun calamitous destruction of ozone.

Why do scientists like Rowland speak out? “Because they’re scientists and scientists are addicted to facts and what facts tell them,” says Baum. “I knew Sherry Rowland pretty well — I was the West Coast correspondent for C&EN from 1991 to 2004 … he was a gracious, dignified, reserved individual, certainly not a rabble-rouser. But he knew that his science was solid and that it told him that humans were doing something that would have catastrophic consequences if they didn’t stop. So he spoke out. Simple as that.”

A new disaster unfolds

Even before the Montreal Protocol was signed, climate scientists were starting to warn that carbon dioxide in the atmosphere would enhance the greenhouse effect and trigger global warming. In testimony to the U.S. Senate in the torrid summer of 1988, NASA climatologist James Hansen linked rising temperatures to rising levels of greenhouse gases from fossil fuels.

The debate over global warming and climate change had begun, and going public put Hansen in much the same position as Rowland had occupied 15 years before. Via email, Hansen credited Rowland and atmospheric scientist Don Hunten as “role models… . They showed that it was possible to do first-rate science and also uphold our responsibility to make clear the implications of our research for society.”

Rowland redux?

Until then, Hansen had been a well-regarded but faintly visible NASA expert in planetary atmospheres. He had studied Venus, where an atmosphere choked with carbon dioxide produces a “runaway greenhouse effect” that raises the surface temperature to 460° C.

After making news in 1988, Hansen retreated from the public discussion of warming, but in the early 2000s, as temperatures continued to rise, he began to speak up again. In 2005, after the Bush White House tried to muzzle him, he went public with a vengeance.

Why? Journalist Mark Hertsgaard, who has written extensively about global warming and repeatedly interviewed Hansen, says he “thinks like a scientist, believes if you find the information, and present it properly, the truth should carry the day. I think he came out of hibernation in 2005 only because he felt he had to. He looked around and saw that the information alone was not carrying the day.”

Hansen’s regular emails combine climate facts with political opinions for a broad audience. For example, a recent commentary argued that “Scientists attempt to communicate, but are flummoxed by the ability of the profiteers to manipulate democracies. The scientific method (objective analysis of all facts) is pitted against the talk-show method (selective citation of anecdotal bits supporting a predetermined position).”

On Aug. 29, 2011, Hansen was arrested at the White House with hundreds of others protesting the Keystone XL tar-sand oil pipeline. Tapping such a vast reservoir of carbon, Hansen believes, will bring us that much closer to a “tipping point” on greenhouse warming. “Now we’ve got the spectacle of one of the world’s foremost climate scientists getting arrested and urging others to get arrested,” says Hertsgaard. “This is way beyond speaking out.”

Hertsgaard, a native of Minnesota, says it’s “very hard for [Iowa native] Jim Hansen the person to speak out.” In the Midwest, Hertsgaard says, “it is just not seemly to draw attention to yourself or bring up a topic that is likely to discomfort others. … but it’s not corny to talk without irony about the importance of doing the right thing.”

The scientific culture

A fully indoctrinated scientist is chary of talking much beyond the lab, Hertsgaard says. “Many scientists very much frown on taking the public agitator role, and that’s another tribute to Hansen’s courage. He was prepared not only to take brickbats from the Exxon-Mobil front groups, but to endure the judgment of his own peers, who said ‘That’s not what scientists do.’ He remembers that he’s not just a scientist, he’s a human being too.”

Despite the successful example of the Montreal Protocol, the global warming problem is vastly harder to solve, says Baum of C&E News. “The scale of fossil fuel use is several orders of magnitude larger …. Humans consume between 80 million and 90 million barrels of petroleum every day, and that represents only about a third of the fossil fuel that is consumed.”

Finally, while the specter of cancer caused by increased UV radiation is unsettling, “people actually like the warmer conditions, at least for now,” Baum wrote. “We didn’t have a winter in Washington, D.C., this year … and people loved it.”

So will the environmental victory over CFCs that started with Rowland and Molina be mirrored by serious action over global warming? Maybe not, says Spencer Weart, a long-time chronicler of warming. Comparing the ozone battle to the fight over global warming “is like comparing a single battle to a world war. Ozone depletion (once the ozone hole was detected) was clearly an urgent problem, with a straightforward solution. But with global warming, it’s hard for people to worry much about something that seems remote in space and time — isn’t it just a problem for polar bears and our grandchildren?”

Slowing warming “will require wholesale changes in our entire world economy,” Weart says. “And that must begin with government regulation of the fossil fuels industry, the largest concentration of economic power the world has ever seen. The pushback has been fierce, beginning with industries that suspected their profits would be restricted, and extending to people who fear governmental threats to their freedom.”

Rowland was once libeled as a Soviet spy, but “Scientists who have put themselves into politics like Jim Hansen … have been subject to ad hominem attacks: crude vilification and direct threats far beyond anything that Rowland experienced.”

Hansen and his colleagues, says Weart, “have persisted nevertheless. For the logic of their scientific understanding forbids them from keeping silent about the dangers they foresee.”

Should an artificial waterway in Chicago be closed to block two highly destructive fish from entering Lake Michigan and then the other four Great Lakes?

On Feb. 27, the Supreme Court said ‘no’ when it declined to revisit an appeal by the State of Michigan, which wanted to compel closure of the Chicago Ship and Sanitary Canal. The canal, created to drain stormwater and wastewater from Chicago, could allow silver and bighead carp from the nearby Des Plaines River to enter Lake Michigan.

Since the two carp, native to Asia, escaped from fish ponds in the South in the 1970s, they have occupied much of the Mississippi River system, and have become extremely abundant in rivers near the Canal. Biologists, state agencies and the Great Lakes Commission warn that once the fish reach Lake Michigan, they will likely spread through the five lakes, then into the St. Lawrence River.

The Great Lakes hold almost 20 percent of the world’s fresh water and border eight states and two Canadian Provinces. Given the silver carp’s fearful jumping habits, and the potential for both species to steal food from the mouths of sport fish, the invasion could threaten recreational boating and commercial, sport and tribal fishing that gross $16.4 billion per year.¹

Although the Great Lakes already house at least 180 invasive species, ecologists warn about irreparable harm from Asian carp. They say prevention is cheaper and easier than eradication — which may be a practical impossibility.

Originally, the watersheds of the Great Lakes and Mississippi River were separate. The two were united by the Chicago Sanitary and Ship Canal, which drains stormwater and treated wastewater into the Mississippi River system.

Don’t fence me out!

Although three electric “fences” across the canal have apparently managed to block the fish from entering Lake Michigan, many scientists view the barriers as stopgaps at best, and Asian carp DNA has been found several times beyond the fences.

While that DNA suggests that the carp are already in Lake Michigan, the fish have not been found there. Still, ecologists, accustomed to studying the disastrous aftermath of invasives on land and in water, would love to protect the Great Lakes from the carp by closing the canal. That would also protect the Mississippi River from invasion from the Lakes.

“The Asian carp situation is analogous to medicine, where an ounce of prevention is worth a pound of cure,” says Jake Vander Zanden, a professor of zoology at University of Wisconsin-Madison, and an expert on freshwater invasive species. “It makes so much more sense to keep them out, rather that let them in and deal with the consequences forever.”

The shipping industry, reliant on these waterways, wants to keep the Chicago waterways open, said Mark Biel, chairman of UnLock Our Jobs by email. “Nobody wants to see the Asian carp get into the Great Lakes… This is, however, a manageable issue that requires a long-term, comprehensive plan, and separation is simply not a solution. Given the size, scope and complexity of separating the two bodies of water, it’s clear that the costs would be enormous and the timeline — if it’s possible at all — would do nothing to address the immediate threat of Asian carp.”

Invasions can be expensive. The Environmental Protection Agency figured that just the invasives delivered in ballast water cut commercial fish landings by 13 percent to 33 percent in the U.S. Great Lakes, at an annual cost of $200 million. The estimate did not cover Canada’s part of the lakes, or species that arrived by other means.

What’s the problem with carp? What can be done to prevent their entry into the Great Lakes and beyond? Are invasive species always so damaging to ecosystems?

What’s the beef about carp?

Asian carp are heavy-bodied fish native to Asia that have occupied large parts of the Mississippi River watershed, where their rapid reproduction, voracious feeding (up to two or three times their body weight in plant and animal plankton per day), and made-for-home-video jumps are making life miserable for native fish and fishing people alike. The two carp considered most threatening to the Great Lakes — silver and bighead — originated in Southern fish ponds, where they were placed as natural vacuum cleaners to suck plankton from dirty ponds.

Since at least 1980, when the escape of the silver and bighead was detected, that voracious appetite was transformed from selling point to sticking point.

You might observe — correctly — that species have been moving since life began. It’s true that invasions are an old story, but it’s only half the story: the process has been force-fed by commerce and technology. “This is a natural process; it was once a trickle, but the rate at which it happens now is so devastating,” says Vander Zanden. “With globalization, trade, travel, things are moving so fast, it’s a fundamentally different process, and the implications are huge.”

It’s impossible to predict exactly how well Asian carp would fare in the Great Lakes; their abundance will depend on temperature, food supply, the emergence of diseases and predators, and factors that we can’t predict. But the lakes have a wide variety of habitats, and inevitably some would be conducive to the invaders.

The fundamental reason why invasive species reach nuisance levels resides in the predators, diseases or competitors they leave behind in their homeland. In the new habitat, the traveling species often gets an unfair advantage, enabling it to grow to astonishing abundance and crowd out native species.

Asian carp provide a perfect example of the process. They were deliberately imported to work on Southern fish ponds, and their ability to outcompete native fish for food and habitat “has led to the widespread establishment of Asian carp in the Mississippi River, impacting the natural balance of the aquatic ecosystem,”².

Can we keep carp from the greatest lakes?

On January 31, 2012, the Great Lakes Commission, an international body charged with maintaining the environmental and economic vitality of Earth’s largest lakes, issued a report describing three options for physically separating the two giant drainages to block invasions in both directions. The report was greeted by a number of officials from the region, including Michigan Senator Debbie Stabenow and Chicago mayor Rahm Emanuel.

The Obama Administration opposes closure of the Chicago canal, and in February it proposed to spend $51.5 million on Asian carp research. The money will buy more trapping and netting, to assess whether the fish have reached Lake Michigan, research on fish trapping with chemical attractants, and noisemakers to scare carp from entrances to the lake.

The focus on Chicago is misleading, according to Biel, who notes that the Great Lakes and Mississippi River Interbasin Study, from the Army Corps of Engineers, found “18 aquatic pathways throughout the region (not just Chicago alone) by which the Asian carp could get into the Great Lakes. The existence of these other pathways, which cannot simply be closed, demonstrates the importance of a regional solution to control Asian carp populations. That’s why we have to expand our sights beyond Chicago to determine a comprehensive control plan that implements measures in all of the pathways… .”

Philip Moy is a senior scientist at the Aquatic Sciences Center at UW-Madison who previously worked on the issue for the Corps of Engineers. “Electric barriers buy us time, and we need to do two things,” Moy says. “We should look into additional barrier technologies that can be added to augment the electrical approach… . We need to look pretty hard at the Great Lake Commission report suggesting that the lake and river can be re-separated. It would cost a lot of money, a century of infrastructure has built up there, but what’s the logic of waiting another 10 years to get started on a project that can take a generation to complete?”

The “mid-system separation alternative” proposed by the Great Lakes Commission was estimated to cost $3.26 to $4.27 billion. The latest federal appropriation for monitoring and research related to Asian carp will bring the three-year cost for controlling Asian carp in the area to $156.5 million.

Separation, Biel wrote, “would effectively end waterborne commerce through the Chicago Area Waterway System. The Great Lakes Commission report mischaracterizes how vessels could move containers around the Chicago rail gridlock, giving the impression that there would be a way to facilitate both separation and continued cargo movement.”

Muscling in on the mussels

There are good reasons why zebra and quagga mussels are often mentioned in discussions about invasives in the Great Lakes. Since the zebra entered the lakes in ballast water used to stabilize ships a couple of decades ago, it has clogged water intakes at power plants and water utilities.

Along with a later arrival, the quagga mussel, the zebra has eaten enough plankton to change the ecology of the lakes, and the zebra is now spreading to smaller lakes and rivers.

To prevent further hitchhikers in ballast water, ships now must replace their ballast water in the ocean with salt water, which carries organisms that are unlikely to survive in the freshwater lakes. “Every ship coming in is inspected by the Coast Guard before it reaches the Great Lakes,” Moy says, “and we haven’t discovered another ballast-related species since 2006. In the lakes, there is a growing spirit of cooperation between the companies that operate ships and the states.”

p. 74, “Aquatic invasive species in the Rio Bravo/Laguna Madre Ecological Region”

Salt-water invaders are carried in ballast water and through the pet and fishery trades.

Species invasions also plague smaller lakes, which explains the growing push to prevent the movement of invasive fish, mollusks and plants, by requiring boaters to clean and dry their boats and trailers as they leave a lake.

In Wisconsin, at least, that effort seems to be succeeding, even though not every boater complies, Moy says. “Some people say, ‘If this guy didn’t do it, it’s not the end of the world if I don’t also,’ but it usually takes multiple introductions over time to establish a population. If we reduce the number of introductions per year, we reduce the potential for establishment. Every person makes a difference.”

Buying time, but could time be on our side?

As ecologists pursue the science of invasives, what to do about the carp now knocking on the door of the Great Lakes? Biel, of the shipping industry, says, “Despite the uptick in hysteria on this issue, Asian carp populations in Illinois haven’t actually moved up river in six years. That said, we fully support funding the existing electric control barriers because their effectiveness has been demonstrated over and over again.”

Despite “substantial strides” in controlling Asian carp in Illinois and Indiana, including a third electric barrier and physical barriers along the Des Plaines River and the Illinois and Michigan Canal, “there’s simply not enough being done by other Great Lakes states,” Biel says. “Continued calls for lock closure remain a higher priority for our neighbors and other like-minded groups than actually implementing tactics for prevention.”

During the years it would take to seal the Chicago waterways, control technology may improve, says Moy, who points to fresh ideas from the U.S. Geological Survey. Instead of using the pesticide rotenone as a “big hammer” to kill all fish, he says, the Survey is testing a coating for rotenone that would make a deadly fish feed. Once sprinkled in the water, carp and other filter feeders would eat the feed, but only Asian carp have the enzyme that can dissolve the coating to release the rotenone. “It’s much more specific; an elegant application that takes advantage of the fish’s feeding behavior and internal physiology, using an existing, certified” chemical agent, Moy says.

There are benefits to working several angles at once, Moy adds. “These invasions are not inevitable. We can reduce the rate of invasions and the number of introductions per year, and that reduces the likelihood of establishment, and each year we delay introduction to a lake gives research time to come up with a solution.”

In hot, dry places, water recycling has joined water conservation as a weapon against water shortages. After being treated at a sewage plant, wastewater is increasingly used for irrigation, industrial purposes, restoring groundwater, and after further purification, for drinking.

Photo: gingerpig2000

He thinks it’s pure water, but could this thirsty hiker be guzzling recycled filtered, treated, oxidized, and disinfected, sewage water?  Could that be safe?

About 0.1 percent of the municipal wastewater treated in the United States is reused for potable (drinking) water, according to a new National Research Council report. That may sound trivial, but “reclaimed water can account for the majority of the drinking water supply in some areas,” the report said.

In general, those areas have taken every reasonable measure to clamp down on water waste before embarking on the more dicey path of reuse. Drinking water is a small part of the growing movement toward reuse; far more common is the recycling of water for irrigating farms and landscapes, recharging groundwater, and for cooling generators and other industrial equipment.

But recycling for potable water is a growing trend in the Middle East, Australia, California and Florida. Miami-Dade County, Florida is about 80 percent through a project at a sewage plant that will use microfiltration, reverse osmosis, advanced oxidation and ultraviolet disinfection to disinfect partially treated wastewater. Each day, 21 million gallons of water “whose quality will be near that of distilled water” will be piped from a moat at the Miami Metrozoo. From there, the water will percolate into the ground to recharge groundwater.

The interest in reuse coincides with a need to update potable water-treatment plants, to the tune of $200 to $300-billion over the next 20 to 25 years.

In 2002, Florida was recycling the most wastewater, followed by California, Texas and Arizona.

The 2004 Guidelines for Water Reuse from the Environmental Protection Agency (EPA) estimated total U.S. water reuse at 1.7 billion gallons per day, with a growth rate of 15 percent per year.

But that’s just an estimate; the comprehensive Research Council report could not find solid numbers on current water recycling in the United States. “In 30 years we have not made a concerted effort in the United States to even figure out how much water we are reusing,” says Anders Andren, a professor of environmental chemistry and technology at the University of Wisconsin-Madison, and director of its Sea Grant Institute.

Globally, the estimate on total (not just potable) water reuse was 5.5 billion gallons per day.

Drink in the irony

If you’re gagging at the idea of guzzling highly treated wastewater, you may already be doing so, courtesy of “de-facto reuse.” The treated effluent discharged by wastewater plants often winds up in rivers, streams and lakes, and can easily enter intakes at downstream water utilities.

“Nobody has tried to figure out where we are in the United States by doing a quantitative survey of de facto reuse,” says Andren, meaning an unknown number of water utilities are delivering drinking water containing an unknown amount of treated wastewater.

If drinking water meets federal water-purity standards, it’s safe, but the issue of de facto reuse does merit further study. “This is the kind of thing every water system ought to be looking at, where the source water is coming from, and what is its quality,” says Henry Anderson, adjunct professor of population health science at the University of Wisconsin-Madison. In most cases, he says, the quality of the intake water is already a factor in deciding how to treat potable water.

On a per-capita basis, Israel, Singapore and Australia are leaders in water reuse. In every case, the local culture, economy, environment and demand for water affect how water is treated and used.

Here, we’ll concentrate on drinking water — the most demanding aspect of water reuse. Because it’s not legal to connect a drinking-water system directly to a sewage plant outfall in the United States, the treated effluent must reside in groundwater, surface water or a container for a while before it is piped to the water-treatment plant.

This delay provides a second layer of protection called “environmental attenuation,” says Anderson, who helped write the recent Research Council report. “The concern of the committee is that no system works with 100 percent efficiency all the time. If you are using a membrane to treat wastewater and it tears … we want multiple layers of protection.”

During attenuation, the treated wastewater can be mixed with surface water or groundwater, and then the water will go through the complete process for treating potable water, Anderson says.

How clean is safe?

Science and technology play dual roles in the adoption of water recycling. Improving water purification technology is offering an increasing number of choices. But technology costs money, and drinking water that comes from ground- or surface water is almost always cheaper than reclaimed drinking water.

But science is also able to detect an increasing number of contaminants in drinking water, and at ever-lower doses. In recent years, this analytical equipment has raised worries about hormones and pharmaceuticals in wastewater that have added to traditional worries about pathogens.

However, these highly accurate chemical-detection methods can raise spurious warnings, says Andren, an expert in water purification techniques. “Analytical capacities are such now that you can find literally everything, but they may pose no health hazard at those concentrations. It’s getting to the point that we can detect a thousand molecules in a liter of water, but this does not necessarily mean there’s anything wrong with the water.”

How it’s done

Water treatment plants come in two varieties. Some treat sewage, and others treat drinking water. In essence, water recycling creates a loose connection between these two plants, although federal law requires that treated wastewater be mixed and stored before it enters a plant treating potable water.

Both types of water plant already use multiple steps for treating water, but recycling has entailed an increase in the amount and intensity of treatment.

The specific treatment methods depend on the nature of the incoming water stream, which could come from sewage treatment plants, street runoff or industry. “The incoming streams can vary so much, in composition, type, quality and quantity,” he says.

Technologies must be chosen to deal with the situation, says Andren. “In certain instances, the main problem is getting rid of salt, in others it’s getting rid of bacteria, or pharmaceuticals, or organic chemicals or metals. It depends on the source water.”

Many challenges

Even though per-capita use in the United States is declining, recycling makes a lot of sense in water-short regions, says Andren. In the United States, “about 12 billion gallons a day [of 32 billion gallons treated per day] is shot into estuaries and oceans. In areas with generally high populations we are shooting away this water and will never have our hands on it again. If just a part of that could be reused, that would be good.”

But due to cost, recycling will only interest places with significant water shortages, Andren says. “We can do a great job at a cost, we can do anything at a cost.”

Ramping up reuse depends on introducing new technology, but that is a natural outgrowth of the steady introduction of sophisticated ways to clean wastewater and drinking water.

Andren, who reviewed the recent National Research Council report, says, “One of the major recommendations is that we basically have the treatment technology, and the approach to assess the hazards through risk assessment. Now we have to formalize that and work together on federal guidelines on how to start using more reclaimed water in daily life.”

Although a water shortage is not healthy, recycling, even if it increases supply, must still overcome the obvious “ecch” factor. “A lot of people ask, ‘If you have effluent from a sewage plant, and it goes through treatment, would you drink that?’” Anders says. “Absolutely, the technology is there, it’s being done all over the world. Our treatment technology and our ability to determine the quality of the water are such that it can be absolutely safe; it can be better than what you presently get out of the tap.”

Iraq resents American drones that monitor outside the U.S. embassy in Baghdad. Iran is delighted to capture a high-tech U.S. drone. And the United States plans more drone purchases even amid slowing growth of the military budget.

As remote-control airplanes get cheaper and better, drones seem to be everywhere:

And it turns out that drones are ideal for watching wildlife: rabbits, sea lions, gulls and a range of elusive or inaccessible species.

Counting the mini-bunnies

Researchers in Idaho have used drones to track the pygmy rabbit, a hand-size mammal that eats sagebrush. The rabbit, a “species of concern” in Idaho, is already extinct in neighboring Washington State.

Pygmy rabbits are reclusive, spending much of their time inside burrows, says Jennifer Forbey, an assistant professor of biology at Boise State University. Forbey, along with Janet Rachlow at the University of Idaho, the U.S. Geological Survey, and Washington State University, is using used military drones called Ravens to explore how habitat factors like cover, forage quality and temperature affect rabbit populations.

The Ravens are small, and able to carry only one of these instruments at a time:

The drone can cover the entire two-kilometer square site in about three hours, but its gadgetry sees neither rabbits nor their burrows. Because the drone noise would scare the rabbits back into their burrows, the plane does not work when the bunnies are likely to be active.

To find the animals, Forbey says, “We have to walk for days and days, to identify where the rabbits are. We hike around, looking for fresh fecal pellets, fresh digging, fresh clipping on plants.”

But the data on forage quality, combined with tried-and true shoe-leather counting, shows that the rabbits are discriminating eaters. “They are specialized to sagebrush, but not all [sagebrush] plants are created equal, some types are more palatable, and also provide better cover for them,” Forbey says.

It’s possible that in winter drones could get a better picture of rabbit activity by looking for tracks in the snow.

To actually see rabbits from the air without frightening them, Forbey suggests a back-to-the-future approach — perhaps lighter than air craft.

“We are trying to develop some other platforms, maybe blimps, that could stay static over burrows to get infra-red video of rabbits without making noise.”

Although airborne surveys have begun, they are a help but not a panacea, says Forbey. “Not much is known about pygmy rabbits. They are cryptic. You have to spend the time walking the habitat.”

Gulls in Spain

Black-headed gulls nest in large colonies, and like many colonial birds, monitoring from the ground is difficult, and viewing from conventional aircraft can be expensive and confusing.

Pick up a battery-powered, radio-controlled model airplane, and the picture changes, says Francesc Sarda, at the Center for Forestry Technology of Catalunya, in Spain. When the drone flies over at an altitude of 30 to 40 meters, “The gulls hear it, but they don’t identify it as predator, don’t know what kind of element it is, and so they do not care about it.”

In a 2010 study,¹ Sarda equipped the plane with a still camera, pointing straight down. A video camera in the “cockpit” broadcast a live feed to a laptop on the ground, where the “pilot” operated controls.

The plane is “easy to fly, many people do it for hobby,” says Sarda, and it’s affordable — at just 1,400 Euros for the plane and the equipment. Depending on wind, the plane can stay aloft for 15 to 20 minutes, but batteries are cheap, and easily replaced before the next flight.

Water birds often nest in dense colonies, and can be difficult to study. Those that nest on cliffs can be observed from the side. On flat land, wildlife biologists may have to walk through the colony, but “If there are thousands of birds, it’s very difficult to count,” Sarda says.

Encounters with human counters can also annoy the birds, he adds. “In our case, they will fly away, even if there are chicks or eggs on the nest. You have to be very careful.”

The drone sidesteps this problem, he says. “You can do your count, and repeat your sampling” after a week or a month, to assess changes.

Laws about low-level flight are much less stringent in Spain than in the United States, Sarda says, and the system is “very cheap, compared with manned aircraft. You can use it yourself, whenever you want.”

See the sea lion

Sea lions and the fishing industry are squaring off in the Gulf of Alaska, where a rapid population decline of Stellar sea lions has been blamed on a scarcity of the fish they eat. But studying these fearsome and elusive creatures is difficult and data are sketchy, says Greg Walker, who manages the unmanned aircraft program at the University of Alaska. “The sea lion is an endangered species, and it’s affecting the fishery, but the science behind it is pretty spotty. The sea lions that have been monitored are healthy, not starving.”

Fishing restrictions are costly to the industry, and Walker observes that boats are catching more fish in the same amount of time, which suggests no scarcity of prey. “Their technology is no better than it was five years ago, and if they are catching more fish, maybe there are more fish” in the Gulf, he says.

Currently, sea lions are counted by looking at “haulouts,” rocky locations along the shore where these mammals mate and give birth, but the Aleutian Islands are hardly an ideal place to fly, Walker says. Airports can be hundreds of miles apart, and weather predictions cannot accurately say if clouds will block the view, wasting time and money.

Last June, Walker and his colleagues launched a drone from a fishing boat standing offshore. After a 12-mile flight, the drone flew over the colony, without causing obvious disturbance, and obtained video and photos clearly showing the sea lions.

Ironically, the same restrictions on fishing that were enacted to protect the sea lion have made fishing boats scarce. “We started working with a fishing cooperative; would fly off their boat while they were fishing, since they were going to be in the area anyway,” says Walker. “But closing the fishery has meant fewer fishing boats in the area,” and the lack of convenient launch pads could raise the price of drone-based monitoring.

If cost can be contained, larger surveys are possible, Walker says. “We will try to survey more of the island coastline, not just the historic haulouts. We want to know, is this a real population decline, or are they just in another part of the habitat? If you are always looking at the same street address, when someone moves down the street,” you may think they are dead, he notes. “Maybe a more consistent survey would find more of the sea lions.”

Eventually, if he can round up a bigger drone, Walker would like to use synthetic aperture radar, which can see through clouds, and could sidestep, finally, the cloud problem. But he also hopes the drones can fly at 500 feet, beneath many clouds. Flying that low is dangerous for manned aircraft, but that concern does not apply to disposable drones.

Having proved the concept of drone-powered surveillance of the sea lions, Walker and associates are planning to begin a three-week campaign in March.

Stop us from droning on!

Drones have a broad range of advantages compared to other ways of studying the environment. We’ve already mentioned how they can get access to awkward locations without bugging the animals.

Flying low and slow, drones can also identify and measure invasive weeds or many other types of ecological dislocation.

H. Franklin Percival, program leader for unmanned airplane research at the University of Florida, says safety is a critical motivation for using drones. “Low-level manned aircraft is the leading cause of workplace mortality for wildlife biologists. Wildlife biologists do this kind of thing all the time, studying salmon nesting, alligators in Florida, seals in Alaska, there’s a lot of low-level stuff.”

In 2010, a pilot and two biologists died in a helicopter crash while studying salmon nesting on the Selway River in Idaho. “That drives the interest [in drones] now,” says Percival. Before nesting, salmon fan away sand and gravel on the river bottom, “and we can see these from the air.”

FAA blues

In the United States, a major limitation on scientific use of drones comes from the Federal Aviation Administration, which is, rightly, worried about collisions between piloted planes and drones. Currently, the FAA requires that the pilot or a spotter be a licensed pilot, and limits a drone’s range and altitude to avoid danger. Those restrictions raise both the cost and bureaucratic rigmarole, and ecologists and the unmanned airplane industry are hoping for a change.

On Feb. 6, the Senate sent legislation to the President requiring FAA action on the issue within three years, USA Today reports.

If the concern is safety, new, more relaxed standards seem most appropriate to drones that fly short distances at low altitude.

If the FAA redrafts regulations to maintain safety while allowing more civilian use of drones, Forbey of Boise State expects ecologists to be lining up for unmanned aircraft. “This integration of technology with ecology and conservation is really exciting. I think what these planes provide is a spatial level that you can’t get from satellite, and can’t get from being on the ground. Both in terms of the area they can cover, and the type of data they offer, they fill a gap.”

Let a thousand drones bloom

Robot planes and the associated technology of cameras, communications and GPS-based recording of location are moving ahead even as the FAA promulgates regulations. At the University of Florida, Percival, who has directed the development of five generations of a robot plane called Nova, says drones should be designed according to the scientific goal. “What are the data required? Can it deliver that kind of data, and can you do the appropriate statistics to give reliable information? The airplane should be built around your question.”

As drones with ever more sophisticated sensors return a growing quantity of data, Percival favors automating data-processing to spit out reliable data that can be manipulated statistically. “To estimate the number of nesting birds in a pelican colony, we want to differentiate the components in the imagery with a computer as opposed to some guy’s eyeballs.”

Photos show a lot, but they do not automatically reflect reality, Percival says. “Just because we can see well does not mean the numbers are as precise, as accurate, as we’d like.”

Among all animals, amphibians are in the worst shape; fully 30 percent are classified as threatened or endangered. Amphibians – including frogs, toads and salamanders — are under attack by a deadly fungus. They are losing habitat to farms and cities, and collected as food or pets. Amphibians are suffering from chemical pollution and the warming climate.

The present is harsh enough, but the future seems worse.

This week, Nature publishes the first global attempt to forecast the impact of three big threats to amphibians by 2080 – a year chosen to be one century after the study’s baseline data.

By comparing areas with plenty of amphibian species with projections of climate change, land use change and the chytridiomycosis fungus, the researchers forecast a grim future for these cold-blooded, four-legged vertebrates. “The bad news is that more than two-thirds of all high-richness regions will probably be affected, to a high intensity, by one of these three threats,” said lead author Christian Hof, who did the work as a Ph.D. student and post-doctoral fellow at the University of Copenhagen.

The geographic study of data on 5,527 amphibian species found little overlap between the cool, moist areas afflicted by fungal serial killer chytridiomycosis, and the places likely to suffer the worst effects of changes in climate and land use.

And the losers win!

In forecasting the future of amphibians, the study coined two technical terms: “losers” — species that are expected to suffer due to disease or changes in climate or land use, and the less numerous “winners,” which are expected to prosper by 2080.

The projection hinged on whether an expected change would make a habitat more or less suitable to the species, says Hof, who’s now at the Biodiversity and Climate Research Center in Frankfurt, Germany. “We ran a number of climate-change models and based on them, calculated a change in climate suitability for each region across the globe.”

Based on these changes in suitability due to climate, land use and disease, Hof adds, “We calculated the number of species that would probably decline due to a decline in habitat suitability. We classify the species as a loser in a particular region, but that does not mean it will decline across its whole range.”

Overall, the researchers found an increasingly dire future for amphibians. For example, 54 percent of frogs are likely to be “climate losers” in the average grid cell of their model. And heavy impacts are projected for about two-thirds of the regions with the highest species richness in frogs and salamanders.

In fact, the future could be even worse, since the study ignored a number of potentially damaging factors, including chemical pollution from cities, factories and agriculture.

Photo: Robert Fletcher, Ohlone Preserve Conservation Bank

Tougher times might await this prowling California tiger salamander, an endangered California native.

Going down!

It’s frustrating but understandable that the study could not predict rates of decline among amphibians. “For many species, we are not sure about the actual distribution, many have tiny ranges and we don’t know where they occur, so we can’t relate historic changes to, say, climate change. We were very careful not to predict extinctions, based on these uncertainties.”

Data are scarce in the study of amphibians, agrees Anna Pidgeon, an assistant professor of forest and wildlife ecology at University of Wisconsin-Madison. “It’s frustrating, amphibians are out at night, often in remote areas, they are small and many are cryptic, so it’s a huge challenge” to understand their populations and ecologies. “We work with the best data we have all the time … and try to make inferences from what we know about close relatives.”

Pidgeon, an expert on habitat needs of vertebrates, says predicting 70 years into the future is always dicey, but that the study’s analysis of multiple threats and global scope are major accomplishments. “They did a lot of things to make sure they were using consensus data, and that makes it a pretty solid approach.”

Although the study looked at overlapping threats, it did not actually look at interactions between those threats, Hof says. “What needs to be done, and we could not do that with our model, is to look at, for example, how climate change would affect susceptibility to the fungus. How would habitat fragmentation affect susceptibility to climate change?”

Although the study does not suggest practical changes that could sustain amphibians in the short run, “The general conclusion is that it’s very important, when thinking about the future for amphibians, to consider different threats together,” says Hof. “Just looking at one threat will not give us the whole picture.”

– David J. Tenenbaum

In a world studded with intractable conflicts, none seems more nettlesome than he one between Israelis and Palestinians. In this and many other conflicts, people are often trained to believe the worst about the other side, who are variously stereotyped as immoral occupiers or immoral terrorists.

These conflicts, as history has shown, are not ideal for peacemaking based on compromise, and yet the conflicts in Northern Ireland and South Africa have come to peaceful resolutions.

But during the conflict, even mentioning the opposing side can backfire, says Eran Halperin, a professor of political psychology at the Interdisciplinary Center in Herzliya Israel. “When you try to tell an Israeli something positive about a Palestinian, or vice versa, the immediate reaction is defensive. In many cases, they are not willing to hear positive information about the other side.”

A sideways approach, however, may be more effective at changing attitudes and creating a willingness to compromise. In a study just published in Science¹, Halperin and co-authors demonstrated that simply reading a few sentences about the successful resolutions of historic conflicts elsewhere made Israelis and Palestinians more amenable to compromise.

“There are positive pieces of information that the parties could absorb, that could lead to a change in positions,” says Halperin, “but people in almost every group involved in a conflict are not willing to hear it. But if you try to go more indirectly … to talk in a general way, you hope they will apply these beliefs to the other group, and this is what our results show.”

Testing tolerance

In a series of experiments, Halperin and colleagues asked Palestinians and Jewish and Arab Israelis to read a few paragraphs in a supposed “reading comprehension” test. Then, as part of a supposedly different study, the same people were asked about their attitudes toward the opposing side.

The tested paragraphs that contained a more positive interpretation of history strongly affected willingness to compromise to resolve conflicts.

Instead of confronting the subjects by stressing that the other side could change its views, Halperin says, the test paragraphs “say that people in other conflicts went through meaningful change in their positions and behavior, and we expect people to understand by themselves that this can happen here.”

The study opens a crack in the despair aroused by prolonged conflicts, says Halperin. “We have now the first indication of what kind of message we should convey to people, to make them more open to the other side. And we already have preliminary data showing that the exact same pattern occurs in other long-term intractable conflicts around the world.”

Still to come, he acknowledges, is “the biggest challenge, using a larger scale intervention to make these changes.” Using the education system and mass media, he proposes a “simple message: Groups change, and behavior that is violent and immoral is a result of a specific situation, leaders and economics. They are not the result of a long-term culture with a fixed character.”

The intervention was focused on hope, Halperin says. “One of the biggest barriers to peace is because people don’t have hope, they don’t believe that the other group can change. If you don’t believe the other side can change its attitude, and as a result its behavior, there is no reason to offer a gesture or compromise, to take a risk in negotiation, and then you can’t make any progress in any intergroup conflict.”

– David J. Tenenbaum

Burning of the Alaskan tundra can release massive amounts of carbon dioxide, the major greenhouse gas, according to a study published in Nature this week. The Arctic is warming faster than the rest of the planet, causing scientists to wonder what will happen to the carbon that plants have stored in Arctic soils and plant matter, both living and dead.

The new study looked at the aftermath of the Anaktuvuk River wildfire, which burned more than 1,000 square kilometers of tundra on Alaska’s North Slope in 2007. Anaktuvuk burned for almost three months, and by itself, accounted for two-thirds of the total area burned in Alaskan tundra since 1950.

The immediate cause was lightning, but weather played a major role. Between July and September, 2007, the North Slope had the hottest weather in a 129-year record. When the fire was really roaring, daily highs were 5°C to 10°C above average. The Slope also received less than 20 percent of the average rainfall that summer, leaving the tundra abnormally arid.

In 2008, Michelle Mack, an associate professor of biology at the University of Florida and her colleagues visited the area and took samples from 1-square-meter quadrants both inside and outside the fire zone. Mack was in the field in Alaska, alas, and did not answer our emails, but her group calculated that the fire oxidized more than 2 million tons of carbon, which entered the atmosphere as carbon dioxide.

Accounting for carbon

The movement of carbon through soils, ecosystems, waters and the atmosphere is critical to the issue of global warming. Releasing carbon to the atmosphere as carbon dioxide speeds warming; and storing carbon compounds can slow or potentially reverse warming.

The moist acidic tundra under study covers as much as one-third of a billion square kilometers of the global Arctic – making it a major “sink” for carbon dioxide. The 2 million-ton release of carbon was equal to at least 50 percent of the amount of carbon stored annually in the Alaskan tundra, meaning this one fire almost cancelled the anti-warming benefit of photosynthesis in the region.

Chilling news about a burning issue

The link between global warming and fire also appeared in a new analysis of Yellowstone National Park. “Large, severe fires are normal for this ecosystem,” said Monica Turner, a Yellowstone expert and professor of ecology at the University of Wisconsin-Madison. Historically, the entire Yellowstone landscape has burned every 100 to 300 years, but Turner and company calculated that current trends toward hotter, drier summers, mean fires could consume the entire area every 30 years by 2050.

Wildfires are also becoming more common in the normally fire-resistant tundra of Alaska, and for reasons related to permafrost, reflectivity and feedback, the consequences could be dire:

And feedback moves us from the additive realm to the multiplicative one. In the Arctic, feedback also plays a central role related to the release of methane, which has even more warming potential than carbon dioxide. Many warming Arctic habitats have started releasing larger amounts of methane, which could warm the planet, feed back, and stimulate the release of yet more methane.

This feedback, like the one that may be affecting burning tundra, paints a darker picture of what could happen if we ignore the atmosphere and blithely assume that the future will be just like the present.

– David J. Tenenbaum

Uganda is looking for answers as about 20 students and a teacher were killed June 28 by lightning that struck their school in this highland nation in Eastern Africa. With dozens of children also injured by electricity, Ugandans wonder if the serious string of lightning strikes is related to climate changes, or are just the consequence of an unusually heavy stream of moist air coming from the Atlantic.

We can’t answer, but the tragedy did get us Why Filers to thinking about lightning. Although lightning bolts killed “only” an average of 39 Americans over a recent 10-year stretch, the injuries, which concentrate on the vulnerable nervous system, can be severe and lifelong.

Satellites tell us that 1.2 billion lightning flashes occur in the atmosphere each year — although not all reach Earth.

What is lightning? How does it injure and kill? And what has been learned in the past few years from the millions spent studying nature’s electricity?

2003, NASA Johnson Space Center

A string of lightning flashes are seen from space.

Boom-boom room

Thunder — the cracking or rumbling you often hear — is caused by thermal expansion and contraction. Lightning bolts can get far hotter than the sun’s surface — up to 20,000° Celsius. That heats the air, causing it to expand, and starting a shock wave that moves as sound waves — thunder.

If you’re close to the lightning bolt, you’ll hear a cracking; further away, you’ll hear rumbling because that sound has come from several parts of the bolt, and been reflected from buildings and hills.

And yes, if you start counting “one Mississippi,” when you see the flash, you can estimate the distance to the bolt: Light essentially reaches you instantly, but sound takes about five seconds to travel one mile. Divide the number of seconds by five to find miles, or by three for kilometers.

Silence is — mysterious

One of the many lightning mysteries is this: Sometimes you hear the thunder, and sometimes you don’t. For example, “heat lightning” is an eerie, silent flash that often lights clouds in thunderstorms.

The sound has been gobbled by an audio version of the visual mirages that cause trekkers to see water in stone-dry desert. These visual mirages are caused by heat that bends light waves. You look straight ahead, but you actually see the sky, shimmering like a tempting lake.

Similarly, in a thunderstorm, the sharp boundaries between warm and cool air can channel sound waves away from the observer, as you can see from the nifty applet, below.

Much the same phenomenon was noticed during the Civil War, when artillery was visible in the distance but audible only in some parts of the battlefield.

Go play with lightning.

Nature’s lighting foundry

We think of clouds as billowy places, couches for angels in Renaissance paintings. In thunderclouds, however, air and water – liquid, frozen and in between — may be whizzing up and down at a furious clip — up to 100 miles an hour.

That’s a place where angels fear to tread.

The motion in these cumulonimbus clouds is powered by convection, a force that separates fluids based on density. The dense, cold air falls while the warmer air rises. Smaller water droplets hitchhike up on the updrafts, which can’t support the larger droplets.

Because smaller particles tend to carry positive charges, the movement caused by temperature, humidity and density (which can include snow, ice, and water vapor) segregates electrical charges: The top of a cloud becomes positive and the bottom negative.

Regions of different charge can only exist if surrounded by an insulator — namely air. Insulators, however, eventually fail when they are overwhelmed by electric “pressure.” In a thunderstorm, that “failure” results in lightning.

Hangin’-motor blues

Having trouble envisioning this? Imagine a chain holding a greasy V-8 motor above a ’63 Ford Fairlane in a shade-tree auto mechanic’s backyard. If the engine is too heavy, or the chain too weak, the chain will snap as it is overwhelmed by the gravitational attraction between Earth and engine.

Thunk!

Substitute air’s insulation for the chain, and electrical attraction between positive and negative charges for gravity, and you have a greasy-fingered picture of how air can separate electrical charges during a thunderstorm.

To go further, we need one hunk of physical-science jargon: electrical potential is how fast charge changes with distance, and it’s measured in volts per meter. Electrical potential is the “pressure” that’s “trying” to start an electric current between areas of opposite charge.

(Opposite electrical charges are like young lovers: They will do anything to get together.)

Just as an overweight V-8 can snap a skimpy chain, excess electrical potential can “break” air’s insulation. When that happens, an electrical current — in the form of a lightning bolt — neutralizes the opposing charges.

Flash!

Diagram: Encyclopædia Britannica, Inc.

Lightning leaps between separate negative and positive regions during a storm. Most cloud-to-ground flashes originate in the cloud’s negative regions.

In a cloud-to-ground flash, the huge electrical potential — measured in millions of volts — eventually overcomes air’s electrical resistance, and a “streamer” or “leader” begins reaching, about 50 meters at a time, toward ground. The streamer makes an ionized (conducting) pathway of plasma, allowing current to flow.

Where am I safe?

As the current approaches the ground, its electrical potential can cause a surge of oppositely-charged particles to “reach” up toward it. Because this upward current often springs from tall objects, trees and other tall objects make lousy shelter during a storm.

For a 2001 Why File on lightning, David Rust, who was then director of forecast research and development at the National Severe Storms Laboratory, told us that the safety of a building is determined by the degree of grounding. A steel building that’s securely grounded, he said, will be safer than a wooden one that’s not, even if the steel building is taller. Steel and other conductive metals provide an easy pathway to ground for the lightning, and that translates into safety.

Once the ionized pathway is established, electric currents flow back and forth between ground and cloud so quickly that they appear as flickers rather than separate bolts. (More on lightning safety.)

We’ve heard that a big cloud-to-ground bolt carries one trillion watts of electricity. If that estimate is right, during its fraction-of-a-millisecond life, the flash carries about the same current as the total U.S. generating capability. (Watts measure the flow of electric current at any instant. The more familiar watt-hours measures an hour of flow of a given current; 1 kilowatt hour equals 1,000 watt hours.)

But nobody has figured out how to put this energy to work. Though we have heard one proposal, the currents are insanely high and the strikes are too brief and too unpredictable.

Keeping a close watch on lightning

Our understanding of lightning grows with improvements in technology, and a new instrument on trusty weather balloons has pointed to a surprising source for the electric charge. The process involves a small, spongy relative of hail called graupel, says Don MacGorman a physicist at NOAA’s National Severe Storms Laboratory.

“As graupel accumulates tiny, pristine ice particles, and then falls through liquid water, there can be some charge exchange in collisions where the tiny ice particles rebound,” MacGorman says. In the lab, this interaction seems powerful enough to be main source of electricity – and therefore lightning — in large areas of the storm.

Within a few years, a better understanding of lightning formation could improve predictions, MacGorman says. “We will not be able to say lightning will a hit particular location. Lightning is too random for that, but we are getting to the place where it may be possible to say that a storm will produce a little or lot of lightning, and that would be helpful for storm safety.”

Cloudy picture

The graupel explanation, however, raises a question: If the interaction of water and ice creates the electric charge, why is lightning found in dry sectors of the storm, including the large “anvil” structure that exhausts cold, dry air above the storm? “We have seen lightning initiated almost 100 kilometers from the heavy precipitation area, so something else must be going on in the anvil,” says MacGorman. “This does not accord with how we’d viewed anvils.”

Scientists are also probing cloud flashes, caused by the flow of current between regions of clouds with opposite charges and does not hit the ground. Formerly dissed because they don’t kill people, cloud flashes are getting some respect.

For one thing, they are the most common type of lightning, accounting for perhaps one-quarter of all lightning flashes. Adding cloud-to-ground and cloud-to-cloud lightning gives a better indicator of total storm intensity than ground flashes alone, “which have very little relationship to storm severity,” says MacGorman. “You can have huge ground flashes in a relatively innocuous storm, but total lightning is well related to things that affect severity and strength: the size of the updraft, the amount of ice in the clouds, and so it gives us clues as to how intense the storm is.”

Positively speaking

The biggest recent discovery on lightning, says MacGorman, concerns storms that produce a large amount of positively charged cloud-to-ground lightning rather than the usual negative currents. During a field research program called STEPS, in a lightning-rich region of the high plains, some storms contained negative charges in places that normally would be positive, and vice versa. In these conditions, instead of dropping the normal negative charge to the ground, the lightning bolts were positive.

The unusual phenomenon could arise in clouds containing a high concentration of liquid water, MacGorman says, and that would also raise the odds of large hail. “Hail typically forms because graupel or another seed particle starts collecting liquid water faster than it can freeze, and the water spreads over the surface, then freezes into a solid layer of ice.”

These dense particles are more likely to happen in an area with a lot of liquid water, and therefore, these positive lightning strikes could be a harbinger of large, destructive, hail.

The view from on high

For the next stage in lightning observations, scientists will go to GOES-R, a series of geostationary satellites scheduled for launch in 2015. These high-orbital spyglasses will carry an optical gadget that should “see” upwards of 90 percent of total lightning activity. “The viewing area will cover pretty much all of the continental United States, and parts of Africa and South America, and eventually, half of the Pacific Ocean,” says MacGorman. “This will allow us to detect thunderstorms over the oceans, which we have not had good way to see in the past.”

That should help airplanes dodge storms, but also aid weather prediction, MacGorman says, since thunderstorms can trigger other thunderstorms. They also add water vapor to the lower atmosphere, which also feeds storms.

Nothing light about lightning

Lightning gathers myths. Whether it’s Zeus throwing thunderbolts from the ancient Greek sky, or the moronic misconception that victims become untouchables because they retain an electric charge, these bolts spark the imagination.

But lightning can change your life, as Steven Marshburn, Sr., of Jacksonville, N.C., told us in 2001. Marshburn was struck in 1969 while working in a bank. Although the sky was blue and no storm was in sight, a bolt entered through a wire from the drive-up window.

Afterwards, Marshburn “suffered from severe headaches, chronic daily pain, grand mal [epileptic] seizures, dizziness, problems with my eyes going blurry. Many health problems persist. I have had 20 lightning-related surgeries…”

In 1989, in response to his brush with death, he formed Lightning Strike & Electric Shock Survivors International to investigate the medical aspects of lightning and to support victims and families. In 2001, he told us that members had talked 13 fellow survivors out of suicide.

A shock to the nervous system

Lightning usually kills by attacking the heart, which runs on electrical impulses. While high-voltage electrical injuries often cause severe burns, they are rare with lightning, likely because the bolts — lasting only 0.1 to 1 millisecond –- are too brief to cause severe burns.

Although burns may result if clothing ignites or sweat boils and steam is trapped under clothing, wet, sweaty clothing may actually conduct a heavy current outside the body and reduce the damage.

Raphael Lee, a professor of surgery and medicine at the University of Chicago, and an expert on the effects of lightning strike, told us that most of the initial current in a lightning strike does not pass through the body. However, two electromagnetic phenomena can produce a strong voltage drop across the body:

Strong electric fields are a problem for nerves and muscles, Lee says, because they “have been structured through evolution to be very sensitive to tiny electric fields.” That, combined with their physical length, which spans a large electrical gradient, “makes them very sensitive to lightning.”

Nerve cells can be a meter long, and by extending into different parts of an electric field, they are exposed to high voltages, Lee says. One focus of concern is the cell membrane which can die if strong voltages poke holes in it. Voltage can also wreak havoc in the pores in the membrane, which regulate the cell’s physiology by controlling how ions enter and leave the cell. Normally, for example, the potassium concentration is 1,000 times higher inside a cell, and damage to the pores can result in malfunction or cell death.

Lightning = thunder in the brain?

Although electricity is the natural focus of lightning damage, Lee suspects that an acoustic pulse, or shock wave, plays a major role, and perhaps a dominant one. A lightning bolt is surrounded by hot, ionized gas that arises in nanoseconds or microseconds and whose temperature may exceed 10,000 ° C. “When you heat something in a small area in such a short period, there are going to be shock waves,” he says.

The power of this acoustic wave is obvious when lightning hits and splits a tree, Lee adds. But inside the brain, the shock can trigger traumatic injuries similar to those caused by a roadside bomb or artillery shell.

Neurological injury: no passing matter

Lightning injury can be severe, long-lasting, and hard to treat, and it “may affect any or all parts of the nervous system,” according to Mary Ann Cooper, an emerita professor of emergency medicine at the University of Illinois-Chicago.

In a 2009 study of survivors of lightning and other electric shocks, 78 percent of the survivors had at least one psychiatric diagnosis; many of the troubles related to learning, memory and executive function.

In 2001, Cooper told The Why Files that confusion, caused by slowed information processing, is a hallmark of lightning injury. Symptoms include “difficulty in short-term memory, coding new information and accessing old information, multitasking, distractibility, irritability and personality change.”

Damage to the frontal lobe, the site of much higher thinking, is common, according to Cooper. “Many suffer personality changes because of frontal lobe damage and become quite irritable and easy to anger. The person who ‘wakes up’ after the injury often does not have the ability to express what is wrong with them…and cannot carry on a conversation, work at their previous job, or do the same activities that they used to handle. As a result, many self-isolate, withdrawing from church, friends, family and other activities.”

Cooper said some cell types continue suffering for weeks after the injury, and that nerve cells seem to “spend a long period trying to heal themselves, until finally the cell body is exhausted” and the cell dies. That process accounts for a delayed disability syndrome among survivors.

Help at hand?

Long-term neurological consequences are a major research area, Lee says, because they also occur in traumatic brain injury. “People are trying to sort out what is the best treatment, and understand why some people are more susceptible to delayed neurological problems. The body is very complicated and … the weight of evidence suggests there are genetic predispositions to complications after a blast causes traumatic injury to the brain, and lightning injury may be no different. Many people recover, but some don’t. What is different about the people who don’t?”

– David J. Tenenbaum

Humans and cats go way back. The relationship sprouted around 2000 BC in Egypt, where humans first domesticated felines. Today, more than 90 million cats in the United States alone enjoy the companionship of humans, while another estimated 90 million are stray or feral.

As in most relationships, there are still secrets between humans and their feline friends. But a recent study published in the Journal of Wildlife Management shed light on one secret that may have been nagging cat owners: what do outdoor cats, otherwise known as “free-roaming,” do all day?

Since there are several cat enthusiasts at The Why Files, we, too, wondered about the answer to that question. And the answer belies a few thorny predicaments peculiar to the cat-human relationship.

A day in the life of a free-roaming cat

Decked with radio collars that tracked their every move, 42 free-roaming cats (18 of them pets, 24 of them owner-less) were the stars of the two-year University of Illinois study. The researchers’ goals were to compare what owned versus un-owned cats did all day, where and how far they wandered, and how likely they were to survive in the often risky outdoors.

Certainly, to no cat owner’s surprise, the felines spent much of their time lounging or sleeping, just like their strictly-indoor counterparts. However, the amount of time pet cats versus owner-less cats spent snoozing differed significantly. Pet cats lazed about for 80 percent of their days, while un-owned cats loafed for “only” 62 percent of the time.

“That alone is very interesting. It could be associated with their requirements. It’s possible that the cats without owners have to spend more time looking for resources to take care of themselves,” speculated Nohra Mateus-Pinilla, study co-author and wildlife veterinary epidemiologist at the Illinois Natural History Survey.

Another important finding, according to Mateus-Pinilla, were the differences in the cats’ ranges. While, not surprisingly, un-owned cats roamed further afield than owned cats, Mateus-Pinilla and her co-authors were surprised by how far the stray cats strayed and by the diversity of habitats they skulked in, as compared to pet cats. While most of the pet cats stuck close to home, the most itinerant stray cat wandered around a 547-hectare (1,351-acre) area.

From original map by Jeff Horn

Despite range differences, un-owned and owned cats’ territories can overlap. The red outline shows the largest range tracked for an un-owned cat in the study, and the yellow dot indicates one pet cat’s range.

“Because of the large home range sizes in the evidence of both cats without ownership and cats that are owned, their home ranges are overlapping. And because of the mortality evidence, these animals could be facing a certain amount of risks that we are unable to measure,” said Mateus-Pinilla.

Indeed, the risks of being a free-range cat are much higher than those of indoor cats, and if the cat has no owner, its fate is almost always bleak. In their study, six stray cats died, while only one owned cat died.

Mateus-Pinilla said their study raises many new questions. To The Why Files, however, it seems that living in the company of humans has its advantages for cats. But keeping this relationship indoors may have advantages for wildlife and people too—-implications that drive the otherwise curious research on free-roaming cats.

Too many kitties on the range

While the indoor-outdoor debate lives on in the cat owner community, and regardless of whether or not cats enjoy the out-of-doors, their secret lives outside entail some dirty secrets that are alarming scientists and laypeople alike.

The sheer number of free-range cats, owned or not, has become a conservation and health concern, some scientists say. Like any species, too many can spell trouble.

Cats, by nature, are superb predators. A cat stalking a bird or squirrel is simply doing what cats do. However, their prowess as hunters, combined with their overpopulation, has wildlife biologists and enthusiasts biting their nails over the potential endangerment or extinction of some prey species.

“There are a growing number of landscapes in which free-ranging cats are not only the most abundant mid-sized mammalian predator, but they can outnumber all of the native mammalian mid-sized predators combined. So they really do become the dominant mid-sized predator in many landscapes,” said Stanley Temple, an emeritus professor of forest and wildlife ecology at the University of Wisconsin-Madison, who was among the first to study the ecological impacts of free-roaming cats.

Because of their impacts on both native predators and prey, conservation scientists consider free-roaming cats invasive species. While not the greatest threat to wildlife, they add to the increasingly complex web of existing threats.

Species most at risk of death-by-kitty are birds that spend a lot of time on the ground, small mammals and reptiles, according to Temple. In fact, cats are second to habitat destruction as the cause of bird extinction. Thirty-three bird species have met their fate to the paws of cats since the 1600s.

The world’s ever-shrinking “islands” of wildlife habitat are hotspots of conservation concern over free-roaming cat populations, since the native species in these areas are the hardest hit by invading cats. For example, birds that live in America’s dwindling grasslands or on the increasingly crowded seashore are finding themselves in a precarious situation.

Open and fragmented landscapes, which also include forest outskirts and farmland, are the territories of choice for cats. And, except in subtropical locales, they tend to stick close to humans. Even if un-owned, most cats are still dependent on people for either food or shelter, or both.

“They are remarkably resourceful at taking advantages of the opportunities that we present,” said Temple, who clarified that free-roaming cats are only truly “feral” if they are completely independent of humans.

Their dependency on humans highlights another dilemma: free-range cats can easily spread diseases and parasites that can jump from cat to cat, cat to wildlife, and even cat to human. The list of contagions includes feline leukemia, feline immunodeficiency virus, worms, rabies and toxoplasmosis, a parasite-caused disease that can damage the developing brains of unborn human babies, if their mothers are infected.

Free-roaming cats’ close proximity to both humans and other animals thus creates a potentially strong reservoir for these diseases. While vaccinating both owned and un-owned cats can help reduce the spread of disease, vaccines are not 100 percent effective and the logistics of vaccinating every single cat may be impossible, especially since many vaccinations are annual.

Photo: Rodrigo Basaure

These street cats certainly benefit from a human handout, but do humans benefit from the cats’ potential disease threat?

It’s complicated

Indeed, solutions to these predicaments aren’t easy. While the science may seem to imply that rounding up every cat on the range may be the best solution, the ubiquity of free-roaming cats and the emotions wrapped up in some people’s relationship with felines complicate the matter.

Studies suggest that many free-range cats are people’s beloved pets that are allowed outside, said Temple. But, while keeping every pet cat indoors would significantly and immediately cut the number of free-range cats, not every cat owner agrees that indoor life is best for kitty.

To further complicate things, one of the often promoted “humane” methods of attempting to reduce un-owned cat populations — trap, treat, neuter, release — repeatedly fails. Not only are there always the cats that get away, but releasing the cats back into the “wild” still does not eliminate the risks to wildlife.

Temple believes that for a cat-control method to work, three criteria must be met: the strategy must actually control cat numbers over large areas, it can’t harm any other part of the ecosystem, and it is socially acceptable. The last criteria can be the trickiest to meet and often creates tension between humans.

Photo: Flickr

Is this outdoor kitty taunting his indoor pal? But who has the better life?

“The divide over how to deal with cat overpopulation, in one way, can be simplified as the group of people who are really concerned about ecological impacts of cats versus those that are really concerned about the welfare of individual animals,” said Temple, based on his years of experience conducting public outreach on the issue. He clarified that he likes cats and is actually the owner of a 21-year-old feline.

Temple believes solutions that meet both factions on common ground do exist. Keeping pet cats inside and trapping, treating, neutering and confining un-owned, free-roaming cats are two strategies that meet his criteria. Though, for some people, it will take some convincing.

Mateus-Pinilla was careful to emphasize that their study did not seek to evaluate management options. They were focused on adding to the science and remaining neutral in the debate about solutions to the issue of free-roaming cats.

– Jenny Seifert