The final version of the U.S. Global Change Research Program’s (GCRP) Climate Science Special Report (CSSR) leaves unchanged all the major findings and conclusions contained in a draft of the report that was leaked to the news media and the public in August 2017. The CSSR was assembled by the nation’s most qualified climate scientists, many of whom work for federal agencies and national labs; they assert in the report that “it is extremely likely that human activities, especially emissions of greenhouse gases, are the dominant cause of the observed warming since the mid-20th century.”
More ominously, CSSR’s authors conclude that this warming trend is producing a sea level rise that is accelerating daily tidal flooding in more than 25 Atlantic and Gulf Coast cities; more heat waves; an increase and an expected continued increase in forest fires; earlier spring melt and reduced snowpack with an accompanying impact on local water resources; and the possibility of chronic, long-duration hydrological drought before the end of this century.
The CSSR also states, “The magnitude of climate change beyond the next few decades will depend primarily on the amount of greenhouse gases (especially carbon dioxide) emitted globally. Without major reductions in emissions, the increase in annual average global temperature relative to preindustrial times could reach 9°F (5°C) or more by the end of this century. With significant reductions in emissions, the increase in annual average global temperature could be limited to 3.6°F (2°C) or less.”
These and many related findings and conclusions—backed by voluminous technical studies—were included in the leaked CSSR and so come as no surprise. What is surprising is that the Trump administration has neither run interference on the final report nor voiced significant disagreement with its contents. President Donald Trump, EPA Administrator Scott Pruitt, and other individuals appointed by the president to key environmental and energy positions have generally turned their backs on evidence that points to human causation for relatively rapid changes to the earth’s climate. Mild resistance to the CSSR was voiced by a White House spokesperson.
“The climate has changed and is always changing,” Raj Shah, a deputy press secretary, said in a statement. “As the Climate Science Special Report states, the magnitude of future climate change depends significantly on ‘remaining uncertainty in the sensitivity of Earth’s climate to [greenhouse gas] emissions.’”
So far at least, other well-known climate skeptics have withheld their opinions. For example, the Heartland Institute, one of the leading organizations questioning the prevailing climate science, had no comment on the report, preferring instead to post the results of a recent poll in which 51 percent of respondents said they would not be willing to spend even $1 more on their electric bills to fight climate change.
Those who agree with the report were more vocal.
“Today’s Climate Science Special Report is our most comprehensive and definitive look yet at the massive amount of sound scientific research on climate change, and it’s conclusions are inescapable—climate change is happening right now, it’s hurting American families, and it will get worse unless we act,” said EDF Senior Climate Scientist Scott Weaver. “This report should put any doubts about the existence or the severity of climate change to rest. We cannot afford to ignore this threat.”
The CSSR is volume one of the Fourth National Climate Assessment (NCA4), which is mandated by Congress. In addition to the final CSSR, the GCRP released a draft of volume two, which is called Climate Change Impact, Risks, and Adaptation in the United States. Comments on this draft are being accepted through January 31, 2017, and a final version will be issued in December 2018, says the GCRP. In addition, the GCRP has issued a draft of its 2nd State of the Carbon Cycle Report, which it calls an “important technical input to the NCA4.
All reports are available here.