By Chris Mooney, Juliet Eilperin and Brady Dennis November 3, 2017
Jason Samenow contributed to this report.
The Trump administration released a dire scientific report Friday detailing the growing threats of climate change. The report stands in stark contrast to the administration’s efforts to downplay humans’ role in global warming, withdraw from an international climate accord and reverse Obama-era policies aimed at curbing U.S. greenhouse-gas output.
The White House did not seek to prevent the release of the government’s National Climate Assessment, which is mandated by law, despite the fact that its findings sharply contradict the administration’s policies. The report affirms that climate change is driven almost entirely by human action, warns of potential sea-level rise as high as eight feet by the year 2100, and enumerates climate-related damage across the United States that is already occurring as a result of 1.8 degrees Fahrenheit of global warming since 1900.
“It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century,” the document reports. “For the warming over the last century, there is no convincing alternative explanation supported by the extent of the observational evidence.”
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The Trump administration released a dire scientific report Friday detailing the growing threats of climate change. The report stands in stark contrast to the administration’s efforts to downplay humans’ role in global warming, withdraw from an international climate accord and reverse Obama-era policies aimed at curbing U.S. greenhouse-gas output.
The White House did not seek to prevent the release of the government’s National Climate Assessment, which is mandated by law, despite the fact that its findings sharply contradict the administration’s policies. The report affirms that climate change is driven almost entirely by human action, warns of potential sea-level rise as high as eight feet by the year 2100, and enumerates climate-related damage across the United States that is already occurring as a result of 1.8 degrees Fahrenheit of global warming since 1900.
“It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century,” the document reports. “For the warming over the last century, there is no convincing alternative explanation supported by the extent of the observational evidence.”
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The government is required to produce the national assessment every four years. This time, the report is split into two documents, one that lays out the fundamental science of climate change and the other that shows how the United States is being affected on a regional basis. Combined, the two documents total over 2,000 pages.
The first document, called the Climate Science Special Report, is now a finalized report, having been peer-reviewed by the National Academy of Sciences and vetted by experts across government agencies. It was formally unveiled Friday.
“I think this report is basically the most comprehensive climate science report in the world right now,” said Robert Kopp, a climate scientist at Rutgers who is an expert on sea-level rise and served as one of the report’s lead authors.
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It affirms that the United States is already experiencing more extreme heat and rainfall events and more large wildfires in the West, that more than 25 coastal U.S. cities are already experiencing more flooding, and that seas could rise by between 1 and 4 feet by the year 2100, and perhaps even more than that if Antarctica proves to be unstable, as is feared. The report says that a rise of over eight feet is “physically possible” with high levels of greenhouse-gas emissions but that there’s no way right now to predict how likely it is to happen.
When it comes to rapidly escalating levels of greenhouse gases in the atmosphere, the report states, “there is no climate analog for this century at any time in at least the last 50 million years.”
Most striking, perhaps, the report warns of the unpredictable — changes that scientists cannot foresee that could involve tipping points or fast changes in the climate system. These could switch the climate into “new states that are very different from those experienced in the recent past.”
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A federal scientist involved in writing the report who asked not to be identified, because he was not authorized to speak to the press, said that political appointees made no effort to change the scientific findings after being briefed on them.
[So they are not totally unpatriotic.]
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Meanwhile, the administration also released, in draft form, the longer Volume 2 of the National Climate Assessment, which looks at regional impacts across the United States. This document is not final but is now available for public comment and will now begin a peer review process, with final publication expected in late 2018.
Already, however, it is possible to discern some of what it will conclude. For instance, a peer-reviewed EPA technical document released to inform the assessment finds that the monetary costs of climate change in the United States could be dramatic.
That document, dubbed the Climate Change Impacts and Risk Analysis, finds that in a high-end warming scenario, high temperatures could lead to the loss per year of “almost 1.9 billion labor hours across the national workforce” by 2090. That would mean $160 billion annually in lost income to workers.
With high levels of warming, coastal property damage in 2090 could total $120 billion annually, and deaths from temperature extremes could reach 9,300 per year, or in monetized terms, $140 billion annually in damage. Additional tens of billions annually could occur in the form of damage to roads, rail lines and electrical infrastructure, the report finds.
This could all be lessened considerably, the report notes, if warming is held to lower levels.
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