In what is considered the United States’ most definitive statement and authoritative assessment on climate change science, a massive, congressionally mandated federal report years in the making that includes input from from over a dozen federal agencies and research from thousands of scientists around the world has concluded that climate change is real and humans are to blame for it, directly contradicting the official policy and positions of the Trump administration.
“This report has some very powerful, hard-hitting statements that are totally at odds with senior administration folks and at odds with their policies,” said Philip B. Duffy, president of the Woods Hole Research Center. “It begs the question, where are members of the administration getting their information from? They’re obviously not getting it from their own scientists.”
Global temperatures have reached record highs for three consecutive years, with six of the last 17 years being the warmest years on record. The report says that weather catastrophes, e.g. floods, hurricanes, and heat waves, have already cost the United States $1.1 trillion since 1980, while warning that such unusual events may become common in the near and not so distant future.
“The frequency and intensity of extreme high temperature events are virtually certain to increase in the future as global temperature increases,” the report notes. “Extreme precipitation events will very likely continue to increase in frequency and intensity throughout most of the world.”
In the United States, the report finds that every region of the country has been affected by climate change, including droughts in the Southeast, flooding in the Midwest, and rising air and ground temperatures in Alaska.
“This assessment concludes, based on extensive evidence, 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. For the warming over the last century, there is no convincing alternative explanation supported by the extent of the observational evidence,” the report states.
“Global climate is projected to continue to change over this century and beyond. The magnitude of climate change beyond the next few decades will depend primarily on the amount of greenhouse (heat-trapping) gases emitted globally and on the remaining uncertainty in the sensitivity of Earth’s climate to those emissions,” it adds.
Many of the report’s conclusion’s directly contradict the Trump’s administration’s positions on climate change, e.g. Trump officials like Environmental Protection Agency administrator Scott Pruitt and Energy Secretary Rick Perry say they can’t be sure whether human-caused greenhouse gases like carbon dioxide are the primary cause of global warming.
Christopher Field, the director of the Stanford Woods Institute for the Environment at Stanford University, called that “tragic.”
“This profoundly affects our ability to be leaders in developing new technologies and understanding how to build successful communities and businesses in the 21st century,” Mr. Field said. “Choosing to be dumb about our relationship with the natural world is choosing to be behind the eight ball.”
Climate skeptics criticized the report and the Trump administration for allowing it to be published.
“I really don’t think that determines policy at all,” said Marlo Lewis Jr., a senior fellow at the Competitive Enterprise Institute. Mr. Lewis said he does not deny that the majority of warming is caused by man-made emissions. But, he said, “The thing is, I’m also going to affirm that there are risks of climate policy as well as climate change. To me the real issue is, where do the risks lie? Suppressing your economy is never a good solution.”
The New York Times added:
The report finds with very high confidence that the average annual temperature over the contiguous United States has increased by 1.2 degrees Fahrenheit (0.7 degrees Celsius) since 1986, relative to the previous century. It is projected to rise, scientists said with an equally high degree of confidence, about 2.5 degrees Fahrenheit, or 1.4 degrees Celsius by midcentury. That will mean hotter days and nights, particularly in urban and densely populated areas.
The report finds with high confidence that if greenhouse gas concentrations were stabilized at their current level, the world will still see at least an additional 1.1 degree Fahrenheit (0.6 degree Celsius) of warming over this century.
“This new report simply confirms what we already knew. Human-caused climate change isn’t just a theory, it’s reality,” said Michael E. Mann, a distinguished professor of atmospheric science and the director of the Earth System Science Center at Penn State University. “Whether we’re talking about unprecedented heat waves, increasingly destructive hurricanes, epic drought and inundation of our coastal cities, the impacts of climate change are no longer subtle. They are upon us. That’s the consensus of our best scientists, as laid bare by this latest report.”