In New York and Pennsylvania, a technique that splits rock so natural gas can flow is pitting environmentalists against industry and neighbor against neighbor.

In areas distant from the surge of natural gas drilling that has swept western states over the past 20 years or so, high-pressure fracturing, or “fracking,” has raised a fundamental question: Can a huge supply of deep natural gas be developed without harming rural landscapes and poisoning the groundwater that most people drink?

Nationwide, fracking is now used not only to liberate gas from shale, but also to boost production in the majority of oil and gas wells. In an era of energy shortages, it’s difficult to dismiss a massive new supply of natural gas, the cleanest fossil fuel, and the gas industry is quick to position fracking as a key to jobs, prosperity and energy security.

But critics charge that fracking pollutes water and causes excess noise, truck traffic and health hazards. They reject the conversion of rural landscapes into what they call “industrial landscapes.”

Update Dec. 9, 2011: On Dec. 8, the Associated Press reported on an Environmental Protection Agency finding “that compounds likely associated with fracking chemicals had been detected in the groundwater beneath Pavillion, a small community in central Wyoming where residents say their well water reeks of chemicals.” Despite the differences in geology and fracking technology between Wyoming and the eastern gas deposits, the finding adds fuel to the contention that fracking can harm groundwater. End update.

The middle ground on the fracking debate seems as lonely as the far side of moon. But could both sides have some valid arguments? And if so, where do we go from here?

Context for the contest

Natural gas was once flared off as junk at oil wells, but it began to enter the energy markets in the 1920s. By now, it’s one of the big three sources of energy in the United States, alongside coal and oil.

Ten or 15 years ago, rising prices heralded a shortage of natural gas, a clean fossil fuel containing mostly methane that has become a major energy source for electricity and home heating over the past 50 years or so.

Those prices helped spark a two-legged technological revolution composed of fracking and horizontal drilling. Fracturing rock allows gas to flow. Horizontal drilling allows one well to tap a profitable volume of a thin, gas-rich wafer of deep shale.

The power of this combination is evident in the frenzy to lock up land above the Marcellus shale, a rock body that underlies parts of Pennsylvania, New York, Ohio and West Virginia, and in the rising estimates for future gas production.

At the same time, “fracking” has become the “brand name” for more generalized opposition to gas drilling, and the debate is confused by the fact that many people use “fracking” as shorthand for new gas development rather than the process that breaks rock so gas can flow. This matters: Although fracking fluids can pose a hazard to groundwater, many gas wells contain other fluids that may carry radiation or other nasties that must be removed before the gas is shipped to its destination.

This “produced water” can be hazardous in its own right.

Down Pennsylvania way

Today, the biggest shale-gas development is in the Barnett Shale, around Fort Worth, Texas, site of more than 10,000 wells. But the hottest political debate concerns the Marcellus shale. The Marcellus was consolidated from mud about 390 million years ago into a fine-grained sedimentary rock that trapped methane produced during the decay of organic matter. The low-oxygen conditions protected the methane from oxidation.

The Marcellus shale lies an average of two kilometers deep, far below the groundwater that feeds home and municipal water wells. With an average thickness of about 30 meters, the Marcellus contains an estimated 295 to 2,700 trillion cubic feet of natural gas.

If 10 percent of that gas can be recovered, this amounts to one to 10 years of supply for the United States, which used 21 trillion cubic feet in 2006. ¹

Fracking has been dividing communities in the East, which has seen little of the vast energy development of the West. While some landowners and businesses profit from leases and economic activity related to gas development, others fear for the safety of their well water, streams and air.

Today, much of the concern about fracking focuses on drinking water. According to Food & Water Watch, toxic chemicals in fracking fluid can contaminate water via spills, accidents, improper disposal or poor well construction. Natural gas has entered drinking water, the group notes, during “more than 1,000 documented cases of water contamination near drilling sites around the country.”

Photo: Helen Slottje

This drill worked in Dimock, Penna.

In areas with many gas wells, groundwater pollution cannot easily be traced to a particular well, and it takes some effort to trace the pollution to gas drilling itself. But widespread groundwater pollution can also be virtually impossible to reverse.

One of the more notorious cases occurred in Dimock, a Marcellus-shale town in northeastern Pennsylvania. After drilling started in 2008, 18 private water wells became polluted with methane and other chemicals, turning dishes brown and, according to a press report, residents reported getting sick from drinking the water, or even showering under it.

On Dec. 15, 2010, Cabot Oil and Gas Corp. signed a consent agreement with the Pennsylvania Department of Environmental Protection regarding 18 polluted water wells in Dimock. Cabot agreed to suspend drilling, plug and abandon three gas wells, supply drinking water to 18 houses, test home well water, and “comply with all applicable environmental laws and regulations” when it resumed drilling and fracking in the area.

The Department concluded, but Cabot disputed, that the company had engaged in “unlawful conduct.”

Let a thousand wells bloom!

New York City continues to oppose fracking in its prized watershed in the Catskill Mountains. And fracking opponents scored a victory on Nov. 18, when the Delaware River Basin Commission declined to move forward on a decision to allow fracking in the Basin. Opponents had warned that up to 20,000 gas wells in the area would threaten water supplies for millions.

Many billions are at stake in the debate over shale gas, which ConocoPhillips expects to account for almost half of U.S. natural gas production by 2035. The petroleum giant credits shale gas for a 110 percent rise in U.S. natural gas reserves and resources between 2000 and 2009.

What is fracking?

Hydrofracturing, or fracking, is a stage of “well completion” that follows drilling. Briefly, drillers bore through the surface, insert steel casing and concrete to seal the hole against groundwater, and drill deeper into the rock, repeatedly adding pipe and cement if needed to seal the well from the surrounding rock.

As the drill approaches the gas-bearing shale, it is “steered” into a horizontal direction, then forced through the source rock for hundreds of meters or more. Once the drilling is completed, holes are punched in the lower casing and millions of gallons of frack fluid are pumped into the well at roughly 1,000 times atmospheric pressure.

After some of that frack fluid is withdrawn, production can begin, as gas rises under the influence of the immense pressure belowground. At the surface, produced water and frack fluid are removed before the gas is piped to market.

Fracking in the history books?

The gas industry often meets questions about the environmental aspects of fracking by asking, essentially, “What’s new?” “The history of fracturing technology’s safe use in America extends all the way back to the Truman administration, with more than 1.2 million wells completed via the process since 1947,” says the industry group Energy in Depth.

But fracking “was a rare process” at first, says Geoffrey Thyne of the Enhanced Oil Recovery Institute at the University of Wyoming. For 20 years it usually used water measured in the tens of thousands of gallons (not millions like today) and sometimes sand, says Thyne. But in the 1990s, drillers in Wyoming “did a giant frack. Suddenly the amount of [frack] fluid jumped 10 or 20 times, and suddenly a whole class of resources that was labeled unconventional became accessible.”

Let’s do the definitions:

Thyne notes that in contrast to conventional gas, shale gas requires “a lot more development, more wells and infrastructure, to get the same bang for the buck, and that creates a lot of friction with landowners.”

Jonah, an unconventional gas field in Wyoming “has a well on every 10 acres,” says Thyne, who teaches petroleum geology and hydrogeology. “If you flew over it, it looks like a moonscape, there’s an incredible amount of development. If you bring that into areas that have not had development, people are going to be put back on their heels: ‘What the heck?’”

As the economic benefits of fracking were proven, it became the rule for oil and gas. Over the last 20 years, Thyne says, “we went from a period where one well in 100 would be fracked, maybe one time each, to now, where 90 percent of all gas and oil wells are fracked, and the number of frackings per well has gone from one to as many as 25, done over a period of several months.”

But that growth is both normal and desirable, says Felmy. “Absolutely, it’s been a wonderful development of technology, and like all technology, it takes time to ramp up. Fortunately, [as a result] a bright spot for consumers is the low price of natural gas today.”

Let the debate begin

The impact of fracturing and horizontal drilling is evident in a new estimate from the U.S. Department of Energy, which places the national gas resource at 110 years of current consumption (although by definition not all of a fossil-fuel “resource” can be recovered).

Projections about future production are inherently debatable because the economical amount of any energy resources depends on future prices. Internal emails from the U.S. Energy Information Administration have suggested that estimates of production and profit in the shale-gas boom exhibit signs of “irrational exuberance.”

In 1996, Alan Greenspan, then chairman of the Federal Reserve, used that to describe the “dot-com market bubble.

Natural gas has environmental benefits over coal and oil, including a reduced greenhouse-warming impact. To release the same amount of heat, oil and especially coal release more carbon dioxide than methane.

We have seen an April, 2011 study claiming heavy releases of heat-trapping methane from fracking and drilling make natural gas worse than coal for the climate. Although critics have questioned the study on the ground that the massive releases are both dangerous and uneconomical, methane is clearly entering the atmosphere at some gas operations.

Ozone, which damages the lungs and triggers asthma attacks, forms when sunlight strikes hydrocarbons released from a gas or oil well. The Environmental Protection Agency is studying ozone and smog at a gas field in Wyoming.

In a tight economy, jobs and taxes are big allures of gas drilling. Some landowners have profited mightily by leasing land to gas firms. In 2009, an industry-financed study reported that 622,000 people are directly involved in the discovery, extraction and distribution of natural gas in the United States, and the industry had an estimated, direct economic impact of $170 billion.

Concerns and open questions

There are plenty of concerns about the intensified gas extraction enabled by hydro-fracturing. Beyond the worries about noise, traffic, and the “industrial landscape,” there are other concerns.

Seven hours after fracturing began, more than 50 shallow earthquakes occurred within 3.5 kilometers of a gas-drilling operation in Oklahoma, in January, 2011. According to the Oklahoma Geological Survey, “The strong correlation in time and space as well as a reasonable fit to a physical model suggest that there is a possibility these earthquakes were induced by hydraulic-fracturing,” but added that this is “impossible to say with a high degree of certainty… “

Fluid chemistry

Frack fluid, the liquid used to pressurize and crack underground rocks, is a major concern about fracking. Water, an incompressible liquid, and sand, used to hold open the fractures created by the immense pressure, are said to comprise more than 99 percent of fracking fluid. But the fluid can also contain hundreds of other chemicals to fight bacteria or rust, or to change how the water flows.

Some of the additives are common and low-toxicity, but others, like diesel fuel, are poisonous.

And many are unknown, held as trade secrets. According to an April, 2011 report from Democrats on the House Committee on Energy and Commerce, “Between 2005 and 2009, the 14 oil and gas service companies used more than 2,500 hydraulic fracturing products containing 750 chemicals and other components. Overall, these companies used 780 million gallons of hydraulic fracturing products – not including water added at the well site – between 2005 and 2009.”

The safer components of frack fluid included salt and citric acid, the Democrats wrote, but some components “were extremely toxic, such as benzene and lead.” Methanol, a hazardous air pollutant and human poison, was “the most widely used chemical … used in 342 hydraulic fracturing products.”

To counter suspicion about these chemicals, the industry recently established Frac Focus, a public database on chemicals used in particular wells. Participation is voluntary.

Wastewater disposal

Used fracking fluid needs safe disposal. “We are talking a substantial volume, millions of gallons per well,” Thyne says, “and one-half to one-third of the fracking fluid comes back, and has to be disposed of.”

Gas from many wells contains a second liquid, called “produced water,” that also needs disposal.

“In classic, conventional petroleum, they can reinject everything back into the reservoir,” says Thyne, “but they can’t do that with unconventional gas [because the rock formation is not porous], so we have a sudden surge in material that has to be treated and disposed of; that’s been a real challenge.”

Some of the liquids have been trucked to municipal wastewater plants, which are designed to remove biological waste, not the components of frack fluid.

One of those components, naturally occurring radioactivity, has sparked a flurry of interest among Pennsylvania and federal environmental regulators. The source is radium in the deep rocks; the hazard occurs if this water is released into surface water or groundwater.

Yet as so often in the fracking fracas, much remains in dispute, including whether radioactivity is elevated in rivers that receive fracking wastewater.

Contaminated water emerging from gas wells is often stored in a wastewater pit near the well site, and these pits have been linked to groundwater pollution, as EPA Administrator Lisa Jackson said in June, 2011. “It gets put in these ginormous huge pools and sits there, and that is a source of contamination all by itself, and so we need to determine how to stop that from happening.”

Wasted by the water

In some states, this wastewater can be spread on land, but a 2011 study² demonstrated that the practice can kill plants.

When 303,000 liters of fracking fluid were spread on 0.2 hectares of experimental forest, tree leaves started to brown and curl within 10 days, and 56 percent of the trees were dead within two years. Every surviving tree was harmed.

The research suggested that high levels of salts – calcium and sodium chlorides – was causing the damage. Several states, including Colorado and West Virginia, permit land application, and the test application was below West Virginia’s limits.

Industry is starting to recycle fracking fluid to reduce environmental contamination, but that’s no panacea, Thyne says. “You can recycle to a certain extent, once or twice. By that time, you’ve got to treat the water to get it back to where it was before you put in new additive. Recycling buys you a little time, but it’s not an end game.”

Mad about methane

Although industry argues that not a single case of water contamination has been conclusively attributed to fracking, methane and other contaminants are appearing in drinking water and near-surface geology after the drill-and-frack sequence.

State investigators traced a house explosion in 2007 in Geauga County, Ohio, to a faulty cementing job on a nearby gas well. After the well was fractured, gas pressure built up inside it and nearby rock formations before being released into basements. One house was seriously damaged and 19 were evacuated, but there were no injuries.

In a 2011 study ³ of 68 residential wells in Marcellus shale in Pennsylvania and New York, Robert Jackson of the Center on Global Change at Duke University found, on average, more than 17 times as much methane in wells that were located within one kilometer of a natural-gas well.

As many as 1 million Pennsylvania households rely on private wells for water, the study noted, and in general, the wells are unregulated and untested.

Jackson says the study found no evidence that fracking fluid had contaminated the water wells. “But we see the gas as a warning sign. If methane is leaking, chances are that other things are leaking too.”

The Jackson study was flawed by “a lack of baseline data,” according to Reid Porter, a spokesperson for the American Petroleum Institute. “Most critical: The authors don’t have hard data to show how much methane surfaces on its own in northeastern Pennsylvania. They cite ‘historical sources’ but don’t say how far back those sources go or exactly what the sources are. … Without more data it’s impossible to distinguish between methane emitted naturally and/or from coal mining and methane released by fracturing.”

A baseline would be nice, but the Jackson study did succeed in finding a significant elevation in methane levels closer to gas wells, and isotopic analysis traced that methane to the Marcellus shale, rather than decay of biomass at shallow levels.

Finding a way

So how is methane reaching water wells from deep shale? It could be rising thousands of feet through existing or newly stimulated cracks in the rock, Jackson says, “but the most likely explanation is poor well construction, cementing or casing.”

Petroleum expert Thyne agrees with that explanation, which “means it’s a mechanical issue that can be dealt with.”

Here, at least, API is in agreement. “The energy industry recognizes that well construction is key to community safety,” Porter wrote us. “That’s why API members have developed five documents that specifically and proactively address well construction and environmental protection practices during hydraulic fracturing.”

When API maintains that fracking groundwater has never been polluted by fracturing fluid, it cites two studies:

Industry is fond of quoting EPA administrator Jackson telling Congress that there has never been a documented case where fracking polluted drinking water, but she implied in June, 2011 that such certainty had not been possible: “There are chemicals in the frack water, and until recently, even today, companies don’t have to disclose them, and we at EPA are exempt from regulating them, except for diesel.”

Because gas wells are much deeper than shallow aquifers, Jackson said groundwater pollution can be prevented by attention to the details of drilling, casing, cementing and closing. “If you get a bad operator, someone who is not responsible, who is not seeing how important it is to get this right, they can contaminate an aquifer … so there need to be some standards.”

Is the enemy fracking, gas drilling — or neither?

The gas industry fears legislation that would ban fracking, says Felmy, and it also believes that some of the opposition comes from “anti-fossil-fuel folks who have discovered that a tenet of their opposition, that we are running out of fossil fuels, is suddenly not true. With the technology developments we have, we can produce a vast amount.”

Yet behind all the protest and controversy, there is some constructive movement. Pennsylvania passed an improved well casing standard in February, 2011, so “it’s quite possible that that will go a long way to fixing problems in newer wells,” says Jackson of Duke. New York has not decided whether or how to allow hydraulic fracturing.

In November, the U.S. EPA announced plans for a study of any relationship between hydraulic fracturing and drinking water, with initial results due in 2012. That’s in addition to ozone studies related to gas extraction.

Some changes are likely in the shale-gas industry, Thyne says. “It’s got a lot of newcomers, it’s very much a gold-rush mentality where the profit margins are low. As the industry matures, it will shake out and the big boys will tend to self-regulate both production and environmental standards.”

Oil and gas are secretive industries, and the voluntary website listing chemicals in fracking fluid is a step toward openness. “The public said, ‘If this is not a problem, why won’t you tell us?’” says Thyne. “I sometimes feel the [energy] companies treat the public a bit like children: ‘You don’t want all these details, you just want to put gas into your car.’ But when the well is in your backyard, you want that information. Half the problem will be going away if they are transparent.”

Porter, of the American Petroleum Institute, says, “Disclosure is something we are very much in favor of.”

In deep water?

Just 19 months ago, the Deepwater Horizon drilling rig exploded and sank in the Gulf of Mexico, killing 11, releasing 4.9 million barrels of crude oil, and reminding us that fossil-fuel development can go horribly wrong. Stories from the gas fields remind us that polluted groundwater is difficult or impossible to clean up, even when money is available. Houses atop polluted aquifers are difficult or impossible to sell.

And so the choice is simple: ban fracking, and accept a rising price for energy, or do gas production right, even if that takes more time.

It’s trite but true: Time is money when you are running a gas drilling rig, but haste makes waste. “The Deepwater accident happened because people were in a hurry,” says Jackson of Duke. “I think there is tremendous pressure to move drilling rigs along in the Marcellus. There aren’t enough drill rigs … . The cause of problems here is likely the same as it was with BP: haste.”

Best management practices and standards are important, says Jackson, “but people have to follow them day after day in the field, when they are in a hurry and when nobody is watching, and that does not always happen.”

– David J. Tenenbaum

Twelve years on, and another billion people are sharing the planet.

Starting half a century ago, the Green Revolution doubled or tripled production of the major grains, using modern seeds, heavy use of fertilizer and irrigation. The revolution helped India and China to feed themselves and averted widespread starvation.

Today, an estimated billion people go to bed hungry. Hundreds of millions are stunted by poor nutrition. And by 2025 another billion people will want to know what’s for dinner…

What to do?

After World War II, agronomist Norman Borlaug played a role in founding international farm research stations that invented and distributed seeds and technologies to Latin America and Asia, with a focus on the big three crops: rice, wheat and corn (maize).

The green revolution that resulted gave a dramatic boost to farm production. But population continues to rise, and funding for food projects tapered off after the initial gains were realized.

The green revolution averted massive starvation “in some situations, but in others, especially Africa, it failed terribly,” says James Lassoie, a professor of natural resources at Cornell University, and leader of Agriculture Bridge, which attempts to harmonize agriculture with conservation.

Small could be beautiful

As the green-revolution research organizations continue working on high-yield crops, a newer approach to raising food production is emerging that concentrates on methods and technologies that can be built and maintained locally.

For reasons related to economics, environment, and efficient technology transfer, the new projects have steered away from large-scale provision of food, equipment, seeds and fertilizer, and toward social and environmental goals. Many projects work in Africa, where food and population problems are most acute, and with women, who do most of the farming.

Although few would discount the role of high-yield seeds in feeding seven billion, “Economic development needs to support both environmental protection and livelihoods,” Lassoie says. “Technologies are not going to help if they don’t also deal with the social and political dynamics.”

Our look at a few of these projects only offer an educated scanning of the horizon. We neither visited these projects nor possess a crystal ball, and so can neither vouch for their results nor predict the end game. But farmers are smart people who gravitate to things that work — if they fit the local culture, economy and environment.

Enough introductory blather. Let’s take a look!

Progress on one acre in Kenya and Rwanda

Africa’s agriculture is dominated by “small-holders,” people who work an acre or two, mainly with family labor, and are an increasing focus of attention in the effort to feed ourselves.

Services are loans, not gifts, and as is common with micro-lenders, borrowers join small groups that guarantee each loan. One Acre says 99 percent of its loans are repaid.

The fund’s advisors offer farming advice during weekly visits that emphasize profitability as much as productivity. For example, because prices are usually lowest during the harvest, the advisors suggest that farmers hold on to their crops for a few months.

One Acre says its growing and marketing strategies double the average farmer’s income, allowing small-holders to pay school fees and buy land to improve family income and food security. One Acre is reaching 55,000 families in Kenya and Rwanda, and aims to enroll 150,000 families by 2013.

Fish, water and wetland in Uganda

The realization that healthy ecosystems improve water quality and store carbon from the atmosphere has spawned a system called “payment for ecosystem services.” After all, if people downstream are getting clean water or hydroelectric power from a well-forested watershed, that should be worth paying for…

It’s a simple concept that conceals any number of complexities, but these payments do bring in outside money that can support environmental improvements.

In densely populated southwestern Uganda, the organization Nature Harness Initiatives is combining payment for ecosystem services with collaborative management to protect the environment of a wetland in the Kanyabaha-Rushebeya region.

The wetland provides fish for food, bees for honey, and fiber for thatch, mats and baskets, but farming and deforestation by people trying to make a living are causing serious soil erosion, harming the wetland and its many human and non-human residents.

Although baseline data on water quality is short, Nature Harness is convinced that it’s program works, and can be expanded to regions with similar problems.

Growing new farmers in Uganda

In Uganda – and elsewhere — farming is often seen as an occupation best suited to school dropouts and people who cannot afford college. Could interesting the younger generation of Ugandans in growing vegetables reverse this trend?

Through the Project for Developing Innovations in School Cultivation, more than 1,100 children in at least 31 schools have transformed schoolyards into gardens as they learn to grow local crops with traditional and environmentally-minded methods.

Project DISC was inaugurated in 2006 to combat rising food shortages and preserve Uganda’s culinary traditions. By allowing children to experience growing, tasting and cooking fruits and vegetables, it is cultivating a generation that values agriculture and quality, local food.

(The whole setup reminds us of the U.S. urban farming movement.)

The farming lessons includes methods for sustainably growing crops in Uganda’s increasingly hostile climate, as the children learn about raised gardens, drip irrigation and drought-tolerant crops.

Project DISC does face obstacles, such as Uganda’s staggering population growth and declining soil fertility. All the more reason to encourage young Ugandans to see agriculture as a respectable livelihood, rather than a last-resort job.

Community grazing rights in Mongolia

In land-locked Mongolia, 2.7 million people coexist with about 10 times as many horses, cattle, sheep, goats and camels. The people of Mongolia have followed their animals for centuries, living a nomadic life in portable shelters called gers.

This windy, dry and cold land exists at the mercy of the weather; the harsh winter of 2010 killed 20 percent of the country’s livestock. Meanwhile, overgrazing is promoting erosion and making the pastures less productive, while the Gobi Desert encroaches from the South.

It’s a classic case of the “Tragedy of the commons,” the idea that resources owned by all are protected by none.

To avert tragedy, Mongolia is experimenting with “co-management,” a system for making joint decisions about the grasslands to maximize benefits and prevent long-term degradation. In co-management, groups of herders contract with the government to assume the regulation and protection of tracts of land. Contracts are adapted as needed during annual renegotiations.

The result has been a reduction in herd size and an attempt to breed better animals to maximize profits from a resources that is now managed with an eye to community prosperity. Evaluations say the process is raising family incomes by 5 to 10 percent annually, and the idea is catching on elsewhere in Mongolia and Central Asia.

Banking on the harvest in Niger

In many lands with poor people and marginal agriculture, the months before harvest are called the “hunger season.” In Niger, in the dry Sahel region just south of the Sahara Desert, the hunger season has been exacerbated by droughts and locusts.

Niger is second to last in the United Nations Human Development Index.

Micro-lending is catching on as a way to fight poverty, but there’s a twist in Niger: Instead of lending money, the Project for the Promotion of Local Initiative for Development in Aguie lends grain through “soudure” (pre-harvest) banks.

The cooperative buys grain from local farmers, and lends it when needed at 25 percent interest, a fraction of what moneylenders charge.

By the middle of 2010, about 168 soudure banks, managed by over 50,000 women, were storing enough millet – a local staple grain — to feed 350,000 people for at least a month. That storehouse helped villagers survive the hunger season (see #38) during the spike in global food prices in 2008.

Beating hillside erosion in Yunnan, China

After a devastating flood in 1998 in Southwest China (blamed largely on deforestation of steep slopes), a new reforestation project focused on planting trees that generate income. (Reforestation projects can drive farmers and herders from their land by planting trees that may offer long-term environmental advantages but do not provide income to local people.)

The World Agroforestry Center has sponsored a different approach to reforestation on a 42-square-kilometer watershed in Yunnan Province. The project began with a collaborative design process that focused on using trees for food, forage or other purposes.

Walnut trees provide edible nuts. Beneath the trees, medicinal herbs are planted as a cash crop. Women may spend four hours a day collecting firewood, but new fermentation devices transform pig dung into biogas for cooking.

Although the project is said to be working on the small scale, and is producing enough income so parents can send kinds to school, these techniques will only provide a meaningful benefit once they are applied more broadly.

WFARM-TV in Benin

Rice, a staple crop and food through much of southern Asia and tropical Africa, is usually grown on small farms. To stimulate and propagate farmer creativity, Africa Rice develops short videos with significant input from local farmers, and distributes them across the rice-growing region.

Farmers are inherently interested in the ideas of other farmers, and seeing their innovations legitimizes farmer experiments and leads to further improvements.

The 10- to 20-minute videos cover such topics as preparing land, transplanting seedlings, managing weeds and harvesting the rice. AfricaRice distributes the videos through farmer associations; the farmers line up the video equipment and stage the screenings, which are often held outdoors.

By 2009, 11 videos were available to communities in Africa; some have been translated into more than 30 African languages and/or been transcribed for radio broadcast.

– David J. Tenenbaum

Seven viewpoints

Introduction

Katharine Hayhoe

Richard Alley

John Nielsen-Gammon

John Williams

Michael Notaro

Kent McGregor

Kevin Trenberth

Drought and searing heat in Texas: Is this the face of global warming?

Courtesy Eric Bruning, Texas Tech University Atmospheric Science

The cold front that blew through Lubbock, Texas on Oct. 17 raised a dust storm not seen since the 1930s Dust Bowl. The dust storm, seen in this movie, is called a “haboob,” an event more common to Saudi Arabia than Texas.

On Oct. 17, a cold front blowing through Lubbock, Tex. raised a red dust cloud that recalled the awesome Dust Bowl of the 1930s, an epoch of drought, enormous dust storms, poverty and social upheaval that depopulated the Great Plains.

The 2011 dust storm served as an exclamation point on a cruel Texan summer, with drought, wildfires, and temperature records that would not quit. On Oct. 19, the Lower Colorado River Authority, source of much water in the Southwest, warned customers that the drought was likely to force another 20 percent cut in water supplies.

On Oct. 18, Texas Lt. Gov. David Dewhurst instructed the state legislature to study drought-related problems like helping homeowners protect against fire, and ensuring that utilities would get enough water to cool their generators.

As far as we could tell, the multi-pronged assignment did not mention something that many observers think contributes to heat waves, fires and droughts: climate change.

Many recent “natural” disasters have raised the same question: Is the no-sense-denying-it-any-longer human-caused planetary warming intensifying devastating hurricanes, giant rainfalls and snowfalls, or the deadly heat waves in Europe (2003) or Russia (2010)?

Despite political skepticism in the United States, the scientific study of changing climates has grown exponentially for 20 years. In 2009, almost 14,000 research reports focused on climate change, and 20 scientific journals are devoted to the issue.

UPDATED NOV. 18: Today, the New York Times reported that a United Nations panel has concluded that “At least some of the weather extremes being seen around the world are consequences of human-induced climate change and can be expected to worsen in coming decades. It is likely that greenhouse gas emissions related to human activity have already led to more record-high temperatures and fewer record lows, as well as to greater coastal flooding and possibly to more extremes of precipitation, the report said.”

Enough introductory blather. Let’s ask some experts: Is the hot, dry weather in Texas a reflection of global warming? Or is it just proof that the essence of weather is its natural variability? The Why Files talked to seven climate scientists. Peruse their viewpoints in the box above.

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

Southwest fires still ablaze

Last week, New Mexico’s famous Los Alamos National Laboratory, home of the atomic bomb, was shut down when a wildfire exploded from 2,000 acres to 49,000 acres over 24 hours, forcing the evacuation of the town of Los Alamos.

A wildfire that started May 29 in droughted Arizona scorched 538,000 acres – the largest in the state’s history.

Historically, wildfires have been usually battled as threats to life, limb and property. But scientists and land managers now see them as a part of nature that can be postponed but not denied.

This edition of The Why Files examines the ecology of fire in the forest.

For a century, the highly successful Smokey the Bear ad campaign fueled fear and loathing of wildfires in the United States. Embezzlers have been more popular than wild fires, which scourged the landscape, burned the birds and rendered Bambi homeless. But in recent decades, ecologists have come to three startling conclusions about fire:

Forests afire

One touchstone for the reconsideration of fire was the “catastrophic” conflagration in Yellowstone National Park in 1988 — which, despite the frightening photos, turned out to be a temporary setback for the ecosystem. Still, even ignoring the human toll for a moment, scientists have found that massive debris flows from denuded slopes can permanently alter the landscape.

More recently, discussion has shifted to reducing the intensity of wildfires, and to their interaction with a warming climate. How effective is controlled burning? Are global warming and the likely increase in drought already accelerating wildfires? Will more wildfires turn arid parts of Australia, the American West and Asia to desert?

An old debate

Each fire is shaped by weather, geology, plant life, and topography, which makes them hard to study, let alone control. Beyond harming or killing plants and animals, fires force a broad range of changes in chemistry, pH, microbial activity, moisture, water flows, soil structure and erosion.

The debate over wildfire is old, according to Stephen Pyne, a fire historian at Arizona State University. Although it’s impossible to know for certain the prevalence of fire five centuries ago, for a 1998 Why Files, Pyne estimated that before Columbus, wildfires, often set to clear land for planting, burned five times as much area as today.

Pyne said the debate over wildfire in the United States when the first national parks opened a century ago “mirrored an earlier argument in Europe over the role of fire” in natural landscapes. The European emigrants to the New World associated fire with “primitive” agriculture, and the U.S. government sought to eradicate fire from its parks and forests. The policy of fighting pretty much all fires succeeded at first, Pyne said. “Absolute suppression will work for a number of years, even a few decades, but you are always going to have fires.”

In the long run, he contended, total suppression is futile or counterproductive, since it allows a buildup of fuel that makes future fires larger, fiercer and even harder — or impossible — to fight.

Controlled burns — a forest fire you can love!

In response to this fuel buildup, controlled (“prescribed”) burns have been used for decades to reduce the chance of a catastrophic fire and return forests to a condition adjudged to be more natural. Prescribed burns reduce the amount of fuel, try to remove the “ladder trees” that can carry a creeping ground fire into the treetops, and are the “primary management tool” in the Forest Service region that covers 18 national forests in California.

USDA Forest Service, Rocky Mountain Research Station

Watch this piece of Montana’s Bitterroot National Forest grow denser as fire is excluded and trees are harvested. Before 1895, low-intensity fires burned through this forest every three to 30 years, until people began logging and suppressing fires. Click the link for a more complete explanation.

But prescribed burns are expensive, difficult to pull off (as they require a forest that is dry enough to burn, but not so dry that a raging fire will result), and studies of their efficacy conflict:

Do controlled burns damage trees?

Despite some successes from these deliberate burns, scientists have noted that they are sometimes followed by outbreaks of destructive bark beetles, or that fire in the heavy layer of organic matter left after a century of firefighting can kill tree roots – and trees. In a 2007 report, Sharon Hood of the U.S. Forest Service wrote that prescribed burning “is causing significant mortality of these high-value trees even with low intensity fires.”

In a 2005 test in Lassen National Forest and Lassen National Volcanic Park in California, Hood and colleagues looked at the effect of raking litter and duff away from ponderosa and Jeffrey pine trees before a controlled burn. Raking did not confer a survival advantage, perhaps because trees survived well in both the treatment and control groups, but raking did confer some advantage against beetle attack.

Bigger ecological picture

In the search to find out how fires affect forests, one theme stands out: The aftermath of fires is as varied as their weather conditions, biology and landscapes. In some cases, as we’ll see for Yellowstone, the ecosystem bounces back after a fire. But the results vary, even in one fire in one location. For example, the 2002 study of the Rodeo-Chediski Wildfire (which set an Arizona record at 189,000 hectares) found that about half the area was severely burned, and that many more years would be needed to restore the area despite efforts to replant vegetation and contain erosion. The mildly burned half section, however, had reverted to pre-fire conditions by 2009.

In the Arctic, the aftermath of a fire was much more serious: A report after the 1,000-square kilometer Anaktuvuk River fire in Alaska in 2007 documented a dramatic reduction in stored carbon. The researchers concluded that the growing frequency and intensity of fire would cause major changes in the ecosystem, climate and “the well-being of humans and other animals that inhabit Alaska’s North Slope.” After a severe burn, soil carbon, a key indicator of fertility, is “unlikely to recover to pre-fire levels over the next millennia.”

In general, animals get less consideration than plants in research on the aftermath of fires, but several studies of birds describe changes for better and for worse:

Open-air experiment in Yellowstone…

Much of what we know about the ecological impact of fire has come from Yellowstone National Park, where a giant blaze burned about 45 percent of the 1-million hectare park in 1988. Photos of towers of flame and exhausted firefighters became symbolic of nature run amok. Yet long-term studies of the aftermath produced surprising results, says Monica Turner, a landscape ecologist at the University of Wisconsin-Madison.

By 1998, 10 years after the blaze, Yellowstone was already on the rebound. Fish and mammals had survived the holocaust surprisingly well, and lodgepole pines—which dominated the park for 10,000 years — were poking through the shrubs and weeds, heralding a return of the park’s old ecosystem.

• While it looked catastrophic, Yellowstone’s infamous 1988 fire turned out to be a regular stage of ecological change.
  Photo: Jeff Henry, U.S. National Park Service, 12120
  
• Before: A stand of lodgepole pines tower above spruce and fir in Yellowstone 1965.
  Photo: RG Johnsson, , U.S. National Park Service, 08161
  
• 10 years after: The forest restored itself, as lodgepole pines sprout between dead ones in 1998.
  Photo: Jim Peaco, U.S. National Park Service, 15995
  

On cone-y island?

Why the quick rebound? Although the horrific photos from 1988 suggested that the vast sections of Yellowstone were uniformly charred, the severity varied from place to place. While intense crown fires killed all above-ground vegetation in some areas, trees and plants survived milder ground fires elsewhere, and the “mosaic” destruction allowed rapid, but patchy, regeneration. “In some places, very few trees are coming back, in other we see hundreds of thousands per hectare,” says Turner.

These extremes of tree density after a fire reflect that pattern of fire severity, Turner explains, and the biology of the dominant lodgepole pines. Many of these trees produce cones that, in a fire, open and release their seeds, which confront ideal growing conditions: Bare soil with little competition, plenty of sun, and the weather they are adapted to.

Other lodgepoles, however, release their seeds essentially on schedule, giving them less advantage after a fire. As the difference in tree density plays itself out over the decades, the fire’s imprint on the landscape can persist for more than 150 years, Turner says.

A flowering success

Because the soil was charred only to an average depth of 2 centimeters, and never more than 6 centimeters, some plants resprouted from roots or underground structures called rhizomes. By 1990, wildflowers were already abundant, Turner said. “Regeneration of these plants was very rapid, and it came from within the burned area. Even the really big fires leave a legacy of the plants that were there before the fire.”

In contrast, invasive species, did unexpectedly poorly after the fire, Turner said. “We had hypothesized that there might be an invasion by non-natives; the fires had created so much expansive, disturbed habitat, but the invasives have not appeared to spread, and are still where they used to be, along roads and trails.”

Burn and revive — or not

Over all, the fires had surprisingly little impact on wildlife, says Turner, who studied survival of elk and bison in Yellowstone, and the fire may even have given elk an advantage over the reintroduced wolf. “The young forest that is coming back after the ’88 fires provides quite a bit of cover for elk; the young pines are super-dense, it’s difficult to see your hand in front of your nose.” Furthermore, logs from the fallen trees killed by the fire can conceal elk and interfere with the wolf attempts to run down elk in open fields.

The summary word for Yellowstone is resilience, Turner says. The natural fire regime in the Yellowstone area includes a hot, crown fire “that replaces the whole forest and the cycle begins again about every 120 to 300 years. Big fires at the historic intervals are not detrimental to the system in any way.” Although these fires threaten homes and businesses, “from the perspective of plants and animals, fire is a normal event.”

Wildfires can carry other hazards, however. For example, a 2010 study of dry regions of Southeast Australia noted heavy erosion and debris flows after a big fire, mirroring what has been seen in the arid American Southwest. The debris flows were not seen in wetter forests, however.

Fire in a changing globe

Fire, obviously, removes stored carbon from the forest, making it a potential source of greenhouse warming. But the opposite is also true: global warming seems to cause more fires. According to experts on Western water and climate⁵ rapid climate change is underway in the American West, with:

The “signature” of global warming is already appearing in western forests, agreed a 2006 study⁶ which identified a change starting in the mid-1980s toward “higher large-wildfire frequency, longer wildfire durations, and longer wildfire seasons. The greatest increases occurred in mid-elevation, Northern Rockies forests, where land-use histories have relatively little effect on fire risks and are strongly associated with increased spring and summer temperatures and an earlier spring snowmelt.”

In other words, the increase in large, intense forest fires was more likely due to global warming than to the increased fuel load left by a century of fire-fighting.

Data: National Interagency Fire Center

In the United States, the area burned has gradually increased since 1983.

These changes are evident in Yellowstone, says Erica Smithwick, an assistant professor of geography and ecology who studies the aftermath of wildfires at Penn State. Historically, the “fire regime” — the average time needed to burn the entire area — is 120 to 300 years, but the lodgepole pines that dominate the plateau recover within a century, so the forest has survived regular large fires.

But Smithwick, Turner and colleagues came to an alarming conclusion when they compared projections for temperature and rainfall timing and intensity in 2050 to the history of fires when those conditions prevailed in the past.

Near Ryazan, Russia, 8 May 2011, mcsdwarken via Flickr

Record heat in Russia in 2010 led to a series of huge wildfires.

The interval between fires, they calculated, would be drastically shorter, and that is disturbing, Smithwick acknowledges. “If these projections are correct, there really might be a threshold in the vegetation where it would not be able to recover.”

Such a fire regime, she adds, is “more consistent with lower montane forests [with trees spaced far apart] or non-forests.”

What is the endgame of warmer, drier forests where fires are becoming more frequent? Could fires turn a forest to desert? Yes, according to a 2009 presentation by Daniel Neary of the Rocky Mountain Research Station in Flagstaff, Ariz. “Wildfire is now driving desertification in some of the forest lands in the western United States. The areas of wildfire in the Southwest U.S.A. have increased dramatically in the past two decades” from less than 10,000 hectares per year in the early 20th century to over 230,000 hectares today. “Individual wildfires are now larger and produce higher severity burns than in the past. A combination of natural drought, climate change, excessive fuel loads, and increased ignition sources have produced the perfect conditions for fire-induced desertification.”

It’s impossible to know the outcome in Yellowstone, a jewel of the U.S. national parks, Smithwick says. “I don’t think the ecosystem is doomed, but how do you manage a system like Yellowstone in that context? There should be some opportunity for the ecosystem to shift.” Eventually, grassland may replace forest, she notes. “Ecosystems are constantly shifting; that’s the kind of mindset we need to go forward. But this is a bit of a wakeup call. We are pushing the system, and we don’t know what is on the other side of the tipping point.”

– David Tenenbaum

For controlling agricultural insects, bats are worth at least $3 billion a year to U.S. agriculture, according to a 2011 study from Boston University. “People often ask why we should care about bats,” said study co-author Paul Cryan, a research scientist with the U.S. Geological Survey in Fort Collins, Colo. “This analysis suggests that bats are saving us big bucks by gobbling up insects that eat or damage our crops. It is obviously beneficial that insectivorous bats are patrolling the skies at night above our fields and forests—these bats deserve help.”

As conservation officials scramble to respond to white nose, they are enacting quarantines to prevent people – cavers, bat-lovers and scientists alike – from transporting the fungus between caves. Last year, for example, the National Wildlife Refuge System halted public access to all caves and mines on its refuges, and set protocols to prevent scientists from spreading the infection.

In May, 2011, the Fish and Wildlife Service rolled out a national plan for confronting and controlling white nose syndrome.

But bats can do plenty of transportation on their own. Even non-migratory bats may fly 200 miles between their hibernation site and their summer range, says David Blehert, a microbiologist at the U.S. Geological Survey National Wildlife Health Center in Madison, Wis., and a leader of white nose studies. “They can move large distances, across state lines, so there is potential for significant disease spread based on bat-to-bat interactions.”

What is the white nose syndrome situation now? Why is it so deadly? What bright ideas are afoot to preserve insect-eating bats, and what is the likely end game?

Why deadly?

In the short time since white nose syndrome appeared in 2006, scientists have pinpointed a fungus called G. destructans as the killer. But how does G. destructans do its work? One clue comes from the fact that it only kills during hibernation, when bats live in mines and caves at a rather chilly 7°C. “The fungus only grows in the cold, and when insectivorous bats hibernate in a temperate region, they drop their core body temperature to the ambient level,” says Blehert.

(The fungus is not likely to attack fruit-eating bats, says Blehert, because they do not have long periods of “torpor,” the slow-metabolism hibernation state that is conducive to the white-nose fungus.)

A low body temperature allows the bats to survive winter without eating, but it could also curtail the immune system, Blehert says. “Studies of bat immunology are in their infancy, but based on what is known about the physiology of other hibernating mammals, especially the 13-lined ground squirrel it’s likely that the immune system becomes suppressed, and that leaves them particularly vulnerable” to the fungus.

How does the fungus kill? It apparently does not enter systemic circulation, as internal organs are not damaged. All mammals awaken from hibernation occasionally, but Craig Willis of the University of Manitoba has speculated that infected bats have more waking hours, causing them to run out of energy during a period when they neither eat nor drink.

Blehert and his colleagues favor a second explanation: dehydration. Despite the “white nose” name, Blehert says, the most significant infection occurs on the wings. “The wings of a bat have eight times as much skin as the trunk; it’s a massive, very delicate and exposed membrane” with a single layer of epidermis surrounding a thin layer of connective tissue and some muscles and glands. “The fungus selectively invades the wing skin, and destroys everything in its path,” Blehert says.

Beyond their role in flight, bat wings are also needed to regulate temperature, fluids and electrolytes. “The wings may be the Achilles heel that exposes them to such significant infection,” Blehert says.

Indeed, an emerging disease that is devastating amphibians, the chytrid fungus, also affects the skin, and is thought to kill by causing an electrolyte imbalance. “The amphibian’s skin is very important for the balance of water and electrolytes, which has been the basis for our hypothesis about why white nose syndrome is so deadly. There was a paper¹ in 2009 that demonstrated that a superficial chytrid infection causes an ion imbalance in frogs, causing a disruption of the potassium gradient that causes the heart to stop. A superficial fungal infection causes a cardiac arrest! This is a very different concept than getting athlete’s foot and having an itchy foot.”

Stopping the wave of death

As dead bats pile up in caves, what can be done to stop the spread of G. destructans? The first step, trying to slow dispersal, is already under way in affected states, with restrictions on cave entry, and new protocols for disinfecting equipment and people who have a legitimate reason to visit hibernation spots.

The fungus does respond to common anti-fungal agents, according to a 2011 study, which found, unexpectedly, that the meds worked at the low cave temperatures that the fungus prefers. “The challenge is, how could you use pharmaceuticals to manage a disease in free-ranging wildlife?” says Blehert. “They don’t go to the doctor, and they inhabit environments that are likely contaminated with fungus. Say you could treat bats and cure them of the infection. If you can’t remediate their hibernation sites, they will become reinfected when they re-enter the cave.”

The authors of the anti-fungal study did raise the possibility of using meds to decontaminate caves, but this process is not being done, Blehert says. “Going into a cave with a general fungicide would be like dropping a nuclear bomb on a city. Caves are full of bacteria, fungi, invertebrates and vertebrates that may only exist in that unique ecosystem, and getting rid of such an important group of organisms [fungi] could risk significant unintended consequences.”

Willis has proposed using little heaters, since bats seem to fare better in warmer regions of caves, perhaps because that sustains immune function. Small heaters are being tested as bat refuges in some New York State caves, says Lisa Warnecke, a post-doctoral fellow at Manitoba.

Lessons from Europe

G. destructans is an “emerging exotic disease,” and to investigate such diseases, scientists always want to know how the pathogen interacts with hosts in its land of origin, which seems to be Europe:

In 2009, the fungus was found in a greater mouse-eared bat in France²;

ENLARGE

Photo: Gabrielle Graeter, NCWRC

Is this bat unhappy about the tufts of fungus on its muzzle — or the researcher’s big hands?

During the winter of 2009-2010, infected bats were found in 76 of 98 sites in the Czech Republic; and

A 2010 study³ in Europe found a white nose pathogen in 21 of 23 suspected bats that was “100% identical” to the U.S. pathogen.

Although the fungus been found in at least five bat species in Europe, die-offs have not been seen there, suggesting that something is different about how the pathogen, host and environment interact. Pathogens and hosts co-evolve through time in a complex dance:

The pathogen may become milder, improving its own survival (and that of its host);

hosts may evolve immune resistance; and

hosts can change their behavior to reduce exposure to the disease.

In the lab in Manitoba, Willis and Warnecke are studying how long little brown bats are awake during hibernation, whether the fungus is a necessary and sufficient cause of death, and if the North American or European strains of fungus have different effects on the bats. “If both isolates show the same severity for North American bats, that may mean that bats in Europe have co-evolved with the fungus and are resistant to it,” says Warnecke. “On the other hand, if the European isolate does not cause trouble for North American bats, then the fungus in North America is a mutant that has gotten really aggressive.”

Other factors could explain the lack of disease in Europe, says Blehert. “European bats are larger, which may provide them with more of a buffer against a physical insult like a fungal infection.” The little brown bat, the preeminent victim of white nose, weighs about 6 grams – about the weight of two pennies, Blehert says.

European bats also tend to hibernate in small groups. “They don’t have those 100,000-plus hibernacula like we see in the United States. With fewer animals, the disease transmission dynamic is likely to be reduced, with less amplification of the fungus, and lower rates of bat-to-bat transmission.”

In the long run, Blehert says, American bats may evolve some resistance. “In general, the population decline in caves and mines comes to about 78 percent, but the bats have not disappeared. We would expect something that gets into population to cause high mortality and a steep drop-off in population. Then, with fewer animals around, disease transmission could moderate.”

Although the regional extinction of the brown bat has been predicted to occur 16 years from now, “our bats may ultimately develop population dynamics more like Europe, with fewer animals and moderated disease transmission and progression,” Blehert says.

Evolution, in other words, could select for animals that, for behavioral or immune reasons, are less susceptible to white-nose.

But letting the situation play out without trying to help the bats, Blehert says, amounts to a high-stakes gamble with one of the wonders of the night sky.

In Haiti, the body blows just keep coming. About 200,000 died in the January earthquake. Then the recovery was hampered by poverty, an ineffective and corrupt government, and a long tradition of class antagonism and social chaos.

And now Haiti is stricken by a cholera epidemic that has already killed about 1,300.

Cholera is a fast-moving bacterial disease that causes intense diarrhea and can kill within hours. Despite efforts to contain it, Haiti’s epidemic is spreading from its epicenter north of Port au Prince, the capital, and has reached the vast tent cities that still house earthquake survivors.

In cholera, the Vibrio cholerae bacterium multiplies in the intestines, forcing the patient to release vast quantities of highly infectious watery stool. Lacking proper disposal and treatment, the diarrhea can pollute drinking water and start new infections.
Cholera is vanishingly scarce in the developed world, and cholera thrives on poverty, disorganization and under-development.

Photo: PAHO

Drinking water contaminated with the cholera bacterium is the major cause of new infections. The Artibonite river, a source of drinking water for many Haitians, is suspected to be transmitting the cholera epidemic.

Haiti, where cholera had not been seen for a century, has been rocked by controversy about the source of the bacterium. Some angry Haitians blame United Nations peacekeeping troops for bringing it from Nepal, but at this point, treating patients and providing clean drinking water seems more pressing than doing genetic forensics to track the disease to its origin.

From the viewpoint of V. cholerae, chaotic, post-earthquake Haiti may be paradise, but outbreaks have also occurred in Latin America, Africa and India in recent years. The World Health Organization estimates that cholera annually infects three to five million people and kills 100,000 to 120,000.

Prompt treatment with electrolytes dissolved in clean water can prevent death in 99 percent of cases.

A violent announcement

Cholera announces itself with a sudden, violent outbreak of diarrhea – a “rice-water stool” named for its semblance of water used to cook rice. Diarrhea — and sometimes vomiting — can cause massive water loss and electrolyte imbalance. Muscles cramp and eyes recede into the skull.

Falling blood pressure and oxygen starvation cause a state of shock that can kill within minutes. A graphic description of cholera is mortifying: “A mid-nineteenth-century English newspaper report described cholera victims who were ‘one minute warm, palpitating, human organisms-the next a sort of galvanized corpse, with icy breath, stopped pulse, and blood congealed-blue, shriveled up, convulsed.’”

Saint Nicolas Hospital, St. Marc, Haiti; PAHO

Haiti’s hospitals, like this one north of Port au Prince, are being tested by the cholera outbreak, but most patients can be treated at an early stage with oral rehydration salts.

An incubation period as short as two hours is one reason for cholera’s dreadful reputation, but its efficient spread through contaminated water is another. As Haiti demonstrates, the conditions of poverty, filth and social chaos that help spread cholera also hinder prevention and treatment efforts.

At present, health organizations in Haiti are focusing on sanitation, clean water, hand washing, and other tactics to interrupt the chain of infection. Treatment is taking place in dedicated wards.

To restore the body’s electrolyte balance, patients with moderate to severe diarrhea need treatment with an oral rehydration mixture — essentially a medical-grade sports drink containing sodium and glucose dissolved in clean water. Treatment is simple and many patients need no hospitalization if treated promptly.

In severe cases, antibiotics are used to kill V. cholerae, although the main benefit is often a faster return to health and a reduction in the load of bacteria released in the feces.

Photo: PAHO

A patient in Saint Nicolas Hospital, St. Marc, Haiti, during the cholera outbreak. That hole in the bed accommodates the violent diarrhea that is cholera’s trademark.

Very versatile vermin

The cholera bacterium, like any self-respecting microbe, has evolved genetic tricks for optimizing its survival in changing circumstances. Once it passes through the human mouth, V. cholerae:

Photo: Dartmouth Electron Microscope Facility

The cholera culprit Vibrio cholerae infects its host quickly and spreads easily via diarrhea.

Cholera’s big gifts

Like an execution in the morning, fast-spreading cholera has served to concentrate the medical mind. Cholera was first seen for sure in 1817 in India; the disease then traveled with people and their commerce around the world and eventually gave humanity two durable gifts.

The first gift came when a mid-19th-century outbreak of cholera in London spawned the science of epidemiology — the study of epidemics. The story is often told of how, in 1854, physician John Snow marked where cholera cases lived, and realized that they all had gotten water from the same pump.

Even though the germ theory of disease was yet nascent, authorities removed the handle from the pump and the epidemic subsided. Although that removal is credited with ending the epidemic, it may have already been waning.

Images: Map; Snow: UCLA Department of Epidemiology

This map, drawn by Dr. John Snow (1813-1858), correlated London cholera cases (each marked by a dash) with drinking water from the Broad St. pump. Mouseover image for a photo of Snow, the founder of epidemiology.

Photo: Madison Metropolitan Sewerage District

Sewage treatment is essential for dozens of reasons, but many countries cannot afford expensive treatment systems.

Snow’s achievement is especially awesome considering that the bacteria that causes cholera would not be identified until 1883, by the great German microbiologist Robert Koch.
By correlating a disease with foul water, Snow showed that epidemics could be understood by analyzing the timing and location of the illnesses — two rudiments of epidemiology. And that led to a second gift: As epidemiologists realized that drinking feces was dangerous, not just disgusting, the health-giving revolution of sanitation got under way.

Virtuous vaccines?

Antibiotics kill cholera bacteria. But carpet-bombing with antibiotics (“mass chemoprophylaxis” in medico-lingo) is inadvisable because it stimulates bacteria to resist the drugs.

Vaccines must be given before an epidemic gets under way, and thus are most suitable in regions where cholera is endemic, like South Asia. But oral cholera vaccines are showing progress:

Breaking the chain

Infections are contained by interrupting the chain of infection; and no fundamental scientific or social hurdles prevent this from being done with cholera. Unlike HIV, cholera is not spread by sexual contact. Unlike tuberculosis or influenza, it is not spread by coughing.
Instead, cholera prevention requires attention to boring, even repulsive, topics like safe drinking water and sewage treatment. Granted, the technology can be expensive, but water and sanitation are also the primary defense against microbes, viruses and parasites that cause dozens of other waterborne diseases.

The United Nations’s Millennium Development Goals aim to raise the proportion of people getting clean water and adequate sanitation, but Unicef says progress is mixed: “Two and half billion people are still without access to improved sanitation – including 1.2 billion who have no facilities at all and are forced to engage in the hazardous and demeaning practice of open defecation. The news is better for water: the number of people without an improved source has dropped below one billion for the first time in history.”

Map: Unicef

Improved sanitation parallels national wealth. In Latin America and the Caribbean, 117 million people live without adequate sanitation.

In 2010, 884 million people have no access to “improved” drinking water, including 330 million in Sub-Saharan Africa, 222 million in Southern Asia and 151 million in Eastern Asia.
India and China account for the lion’s share of progress in both water and sanitation. Globally, city folks usually score higher in these basic barometers of human development.
So do rich people.

In terms of public health, clean water, clean air and sanitation are the big three environmental goals. By themselves, diarrhea diseases cause 4 percent of all time lost to illness, when measured by disability-adjusted life years.
The cholera question is scientifically straightforward, and is quickly solved when resources and social organization are available. Yet even if the victims of cholera are poor and powerless, the benefits of clean water and sanitation are so manifold that it’s hard to accept that these basic requisites for health are not for everybody.

But as the population soars, as people continue flooding into shantytowns around megacities, and as income inequality remains a fact of life, we anticipate this is not the last article you’ll read about such an avoidable epidemic.