Humans are the “extremely likely” cause of warmer temperatures observed since the 1950s, according to a report recently released by the federal government.
The U.S. Global Change Research Program is required by law to produce the report every four years. It says every region in the United States experienced warming in 2016. The assessment says the Southwest is projected to become drier, with more intense droughts and a lower snowpack in the Sierra Nevada mountains.
The report is a contrast to the Trump administration’s shift away from a focus on climate change. President Donald Trump has expressed support for the coal industry and has signaled that the U.S. will abandon the Paris Climate Agreement. The first day the U.S. can legally leave the Paris Climate Agreement is the day after the next presidential election in 2020.
"The Climate Science Special report further strengthens the connection between human activity and the climate crisis,” said Eymhy Corpus, Las Vegas Organizing Representative for the Sierra Club's Beyond Coal Campaign.
Corpus said Trump and Environmental Protection Agency Secretary Scott Pruitt need to take science seriously and shift toward clean energy for the future.
“More frequent heat streaks, more intense droughts and stronger wildfires are all evidence here in Nevada, and throughout the Southwest, that fossil fuel pollution is changing our climate,” Corpus said. “We have no time to waste transitioning from fossil fuels to clean energy like solar, wind and geothermal."
Ted Greenhalgh, a UNLV environmental studies professor, said this report assesses all of the research that’s been done since the last analysis was published and compares it to previous data. On climate change, as more research has been done, the data points to human-caused warming, he said.
“Every time we do another study on climate, the results come out and it’s always a revelation of a type. But it always ends up supporting what we think is going on — humans are causing climate change, and we really need to get a handle on this before it starts costing the country more than it already is,” he said.
He said some were surprised to see a report like this come out of an administration whose president has been skeptical when it comes to climate change. Greenhalgh said there isn’t much any president can do to affect scientists, aside from cutting off federal dollars to agencies that fund climate change research and getting them to allocate the money they do get to other types of projects.
“This peer review process we go through, we all watch what goes on so we make sure the science is right,” he said. “That’s not going to change no matter which administration’s in.”
The report predicts a drier Southwest, but Greenhalgh said Canadian research predicts more precipitation in the region. He said warming causes more water to evaporate and gives storms the energy to push all that moisture out of areas such as California and the Midwest, dropping precipitation elsewhere rather than on the farms that need it most. He said forest fires fall on top of longer, more severe droughts.
“When you warm the atmosphere, that changes where rain falls,” he said. “So all those farms are at risk because they may not be in a place where the rain’s going to fall in the future.”
He said the National Atmospheric and Ocean Administration has been tracking superstorm data for almost 40 years. The U.S. has gone from slightly less than three superstorms a year on average to more than 10.
“It looks like we might end up averaging about 14 per year this decade,” Greenhalgh said.
Three hurricanes hit the U.S. this year, one considered a thousand-year event and two categorized as 500-year events. The movement of the El Nino oscillation back toward Australia was expected to cause more storms in the Atlantic, but “nobody expected to have this many really strong storms hit.”
Snow helps keep the Earth cool by reflecting light into space, Greenhalgh said. Global warming lessens snowpacks and reduces the amount of light reflection, causing warming to continue.
Greenhalgh said greenhouse gases keep the world from being too cold to live in. Burning fossil fuels, however, releases more greenhouse gases.
“We’re putting so many more greenhouse gases in the air. The greenhouse gases in the air actually absorb the infrared radiation that would normally go back into space and they absorb it and hold it in,” he said.
The concern, he said, is that humans will reach a point of no return on climate change and the Earth will run out of snow.
“We’re very conscious of the fact that there’s several times when the Earth has had no snow and when it had no snow the oceans were much deeper,” he said. “And we’re really worried about that because we have a lot of people that live along the sea.”
The solution, he said, is to get people to move toward more sustainable sources of energy. Great Britain lessened its total reliance on coal to roughly 2 percent of the country’s energy consumption, Greenhalgh said. The country also held a coal-free day in April.
Greenhalgh said building infrastructure to pipe water where it’s needed most, moving farms to where rain will be falling in the future, planting trees to suck up CO2 and researching expensive geothermal strategies to lessen global warming are all more complex than simply transitioning to clean energy.
“It’s going to be very interesting to see how we try to adapt to this,” he said. “Or we could do the simple thing and stop using fossil fuels and let the Earth cool down.”