“Warming of the climate system is unequivocal,” members of the Intergovernmental Panel on Climate Change wrote in a summary of their latest annual report. And for the warming that is “virtually certain” to have occurred in the last 50 years in the troposphere (the atmosphere nearest to the earth’s surface), they wrote, “it is extremely likely that human influence has been the dominant cause.”
The authors add that concentrations of carbon dioxide, methane and nitrous oxide — all greenhouse gases that contribute to climate change — are likely at their highest levels in 800,000 years, and have increased more quickly in the past century than they did in the last 22,000 years. These emissions must be stemmed to combat the negative impacts of global warming such as rising sea levels and more extreme weather, they wrote.
Three days after the IPCC report was released, Texas Commission on Environmental Quality Chairman Bryan Shaw questioned many of its premises Saturday during a panel discussion on climate change at The Texas Tribune Festival in Austin.
“What we see is greater and greater uncertainty” in the climate models, Shaw told the audience. He said he believes climate change is happening, but on the question of whether humans are causing it, he simply said, “There’s huge opportunities for research.”
Shaw pointed out that warming has not occurred in the past decade and a half, which original climate models had not predicted — a fact many skeptics of climate change have pointed out. He added that water vapor is also a major greenhouse gas that contributes to global warming, suggesting humans might not be a prime contributor.
“That makes no sense at all, period,” said Andrew Dessler, a climate scientist at Texas A&M University who studies the effect of water vapor on the global climate. Water vapor does indeed play a role in global warming, but not to a degree that wipes out the role of carbon emissions, he said.
Shaw is also an associate professor at Texas A&M, in the Biological and Agricultural Engineering Department. At the same university, state climatologist John Nielsen-Gammon has long held the view that human activity is driving a rise in global temperatures. Nielsen-Gammon has said that the changing climate would affect water supplies. As rains hit Central Texas in late September, bringing relief to the dwindling Highland Lakes, he cautioned, “the long-term Pacific and Atlantic Ocean temperature patterns still favor drought in Texas, and probably will continue to do so for another five to 15 years.”
“Whether this drought will last that long or whether Texas will have an occasional wet year within that stretch is impossible to say,” he said.
Carlos Rubinstein, a former TCEQ commissioner who is now the chairman of the Texas Water Development Board, said at the festival it is clear that water availability models in the state will have to change. But when an audience member asked whether the state was looking directly at possible effects of climate change in its water planning models, Rubinstein didn’t explicitly answer, saying only that water planning is done based on the “drought of record,” which is currently the drought that occurred in the 1950s.
Robert Puente, president of San Antonio Water System, said the utility was consulting with climate scientists as the city plans for the future.
Shaw said the science is not yet settled on climate change, and that it would be irresponsible for him to regulate too soon. Without solid science, he said, "I'm left with emotion."
The recent federal regulations proposed to limit carbon emissions at coal plants, he said, are one example of emotions getting in the way of sound regulation.
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This article originally appeared in The Texas Tribune at http://www.texastribune.org/2013/10/01/over-one-week-opinions-differ-wildly-global-warmin/.