Seven viewpoints
John Nielsen-Gammon
Drought, yes, temperature, probably not
“There is evidence that global warming has had an effect on the drought, primarily by increasing the surface temperature, which increases the drought severity by increasing evaporation and water stress, and by decreasing stream flow and water supply,” says John Nielsen-Gammon, Texas state climatologist. “On temperature, it’s not as simple, you can’t make the case based on observation alone, since most of Texas has not seen a long-term upward trend in temperature, because it’s part of a global warming hole in the South-central U.S.”
Warming in the “hole has been masked by natural variability, driven by sea-surface temperature patterns in the Pacific and Atlantic oceans,” Nielsen-Gammon says.
However, “temperatures have been rising in Tex over past 30 years or so, and they are projected to continue rising at similar rates. We think that the hole is filling, and I am afraid of a rebound effect, where natural variability varies in the opposite direction and the temperature rise would be relatively rapid.”
