Just days before Tuesday's U.N. climate summit in New York, a former high-ranking Obama administration official published an article in the Wall Street Journal titled, "Climate Science is Not Settled."
Steven Koonin, physicist and former undersecretary for science in the Energy Department, wrote, "The idea that 'climate science is settled' has not only distorted our public and policy debates on issues related to energy, greenhouse-gas emissions and the environment, but it also has inhibited the scientific and policy discussions that we need to have about our climate future."
The question isn't whether humans are influencing the climate through increased fossil fuel emissions, said Koonin. The "unsettled scientific question" that needs to be addressed is, "How will the climate change over the next century under both natural and human influence?"
Answers to that question, Koonin said, should inform our choices about energy and infrastructure.
Koonin goes on to say that while anthropogenic influences could have serious consequences for the climate, these consequences are "physically small" when compared to the entire climate system as a whole.
"The impact today of human activity appears to be comparable to the intrinsic, natural variability of the climate system itself," wrote Koonin.
A 2013 report released by the Intergovernmental Panel on Climate Change (IPCC) states with "95 percent confidence" that more than half of the increase in the Earth's average temperature over the past 50 years was "caused by the anthropogenic increase in greenhouse gas concentrations," along with other anthropogenic factors.
Concerning the computer models used by the IPCC, there "isn't a useful consensus at the level of detail relevant to assessing human influences," said Koonin.
Koonin went on to claim that these IPCC reports contain, "deficiencies that erode confidence in the computer projections," adding that "work to resolve these shortcomings in climate models should be among the top priorities for climate research."
A recent survey published in the journal of Environmental Research Letters examined over 12,000 peer-reviewed climate science papers and found that 97 percent of them agree that climate change is "man-made."
"Although the Earth's average surface temperature rose sharply by 0.9 degree Fahrenheit during the last quarter of the 20th century, it has increased much more slowly for the past 16 years, even as the human contribution to atmospheric carbon dioxide has risen by some 25 percent," said Koonin.
Another recent publication from the U.S. Global Chance Research Program, which is comprised of 13 U.S. federal agencies, said, "Only human influence can explain recent warming."
However, Koonin claims that the facts demonstrate directly that "natural influences and variability are powerful enough to counteract the present warming influence exerted by human activity."
Considering the political and policy decision at stake, Koonin said "transparent rigor" is necessary, and, to best practice of the scientific method, independent review teams should "stress-test and challenge projections by focusing on their deficiencies and uncertainties."
Koonin ends his article by writing that while many may wish for the "comfort of certainty in their climate science," claiming that the idea of such science is "settled," undermines and retards the progress of scientific enterprise regarding such important matters.
"Uncertainty is a prime move and motivator of science and must be faced head-on. It should not be confined to hushed sidebar conversations at academic conferences."
