Drastic impact of climate change on US, confirmed by government report

The average temperature in the US has drastically risen since 1980. The last decades have been the warmest of the last 1,500 years, as a federal climate change report awaiting approval by the Trump administration shows.

Americans are currently feeling the effects of climate change, as the draft report of scientists from 13 federal agencies states. The report directly contradicts President Trump’s and members of his cabinet’ claims that the human contribution to climate change is unknown and that the ability to predict the effects is limited.

“Evidence for a changing climate abounds, from the top of the atmosphere to the depths of the oceans,” a draft of the report obtained by The New York Times states.

“Many lines of evidence demonstrate that human activities, especially emissions of greenhouse (heat-trapping) gases, are primarily responsible for recent observed climate change.”

Katherine Hayoe, government scientist who worked on the report and professor of political science at Texas Tech University, called the conclusions “the most comprehensive climate science reports”.

The report notes that the world would still feel at least an additional 0.50 degrees Fahrenheit (0.30 degrees Celsius) of warming even if they stopped emitting greenhouse gases immediately. Small differences in global temperatures can impact the climate greatly – for instance, a rise in global temperatures of 1.5 degrees Celsius to 2 degrees Celsius could mean longer heat waves, more intense rainstorms and faster disintegration of coral reefs. Furthermore, it might be possible to attribute some extreme weather to climate change.

The E.P.A. is one of the 13 agencies that have to approve the report by August 18. The agency’s administrator, Scott Pruitt, has said that he doesn’t believe that carbon dioxide is a primary contributor to global warming. “It’s a fraught situation,” Michael Oppenheimer, a professor of geoscience and international affairs at Princeton University who was not involved in the study, said. “This is the first case in which an analysis of climate change of this scope has come up in the Trump administration, and scientists will be watching very carefully to see how they handle it.”

Significant advances have been made that link human influence to individual extreme weather events since the last National Climate Assessment was produced in 2014, as the report says. Nonetheless, uncertainties remain. Scientists believe that the Trump administration might change or suppress the report. However, those who challenge scientific data on human-caused climate change are equally worried that the draft report will be released to the public.

The report cites that the European heatwave of 2003 and the record heat in Australia in 2013 are specific episodes where “relatively strong evidence” showed that a man-made factor contributed to the extreme weather. In the US, the heat wave that rushed over Texas in 2011 was more complicated. That was Texas’ driest year on record and the possible causes were weather variability and La Niña. Another study claimed that climate change made extreme events 20 times more likely to happen in Texas.

In the US, the report states with confidence that the amount and severity of cool nights have decreased since the 1960s. Meanwhile, the amount and severity of warm days have increased. Extreme cold waves are less common since the 1980s and extreme heat waves are more common. The average annual temperature in the US will increase, according to the report. In the future, the recent record-setting years will become common. The temperatures will increase by 5.0 to 7.5 degrees Fahrenheit (2.8 to 4.8 degrees Celsius) by the late century.

The average annual rainfall across the country has increased by 4% since the beginning of the 20th century, according to the report. The Southern Plains and the Midwest are getting wetter, while the West, the Southwest and Southeast are getting drier. The experts made a connection between the contribution of human-caused warming to rising temperatures over the Western and Northern United States, but found no link in the Southeast. Furthermore, the surface, air and ground temperatures in Alaska and the Arctic are rising at a frightening pace that is twice as the global average.

“It is very likely that the accelerated rate of Arctic warming will have a significant consequence for the United States due to accelerating land and sea ice melting that is driving changes in the ocean including sea level rise threatening our coastal communities,” the report writes. Human activity is the main culprit, as the report says.

While the reports doesn’t make any policy recommendations, it says that significant reductions in global levels of carbon dioxide is necessary. Until now, 200 nations agreed to limit or cut fossil fuel emissions, as part of the Paris accords. The study says that global warming will be kept at manageable levels is countries keep their promises. President Trump decided this year to withdraw the US from the Paris agreement, arguing that it is not a good deal for America.