The state of the climate is not strong.
That was the unmistakable takeaway over the last year for scientists who study Earth’s atmosphere. They watched as the planet’s temperature rose to near-record levels, and as hurricanes and fires caused hundreds of billions of dollars in damage. They published research more conclusively linking extreme storms to climate change, and found new evidence suggesting sea levels could rise faster and more dramatically than expected.
Meanwhile, the Trump administration reversed policies to cut planet-warming emissions, worked to open up more of America’s public lands and waters to oil and gas drilling, and announced plans to pull out of an international agreement to fight global warming. Leading the charge were Environmental Protection Agency Administrator Scott Pruitt, Interior Secretary Ryan Zinke and other top officials who have either questioned or outright rejected the overwhelming consensus among climate scientists that human emissions are heating the planet.
President Trump probably won’t talk much about climate change in his first State of the Union address next week. But according to several prominent climate scientists interviewed for this article, the biggest climate story of 2017 was extreme weather.
Hurricanes Harvey, Irma and Maria caused a combined $265 billion in economic losses, federal officials estimate. Wildfires in California and other Western states added another $18 billion in damage. While global warming didn’t cause those events, scientists say, it almost certainly made them bigger and more intense. Record-hot ocean waters and a warming atmosphere fueled the storms that destroyed Puerto Rico’s electric grid and brought unprecedented rainfall to Houston. In California, meanwhile, a scorching summer followed by a bone-dry winter primed the state for its largest-ever wildfire.
“This is the way climate change affects things. You cross thresholds. Things break,” said Keven Trenberth, a senior scientist at the National Center for Atmospheric Research, a federally funded lab in Boulder, Colo. “And as a result, instead of $2 billion worth of damage, you have $200 billion.”
In the past, some climate scientists have been hesitant to definitively link global warming to extreme weather, saying there was still uncertainty in the science. But as scientists have refined their techniques and studied recent disasters, they’ve generally become more confident linking rising temperatures to more intense storms, floods and wildfires.
Kerry Emanuel, an atmospheric scientist at the Massachusetts Institute of Technology, published a paper 31 years ago predicting storms would get more intense as the climate warmed. Now he’s seeing it happen. A few weeks after Harvey, he wrote a paper estimating that the odds of a storm dumping as much rain as Harvey dumped on the Houston area had become two or three times higher since the late 20th century.
At the same time, Emanuel said, hurricanes aren’t necessarily becoming more common.
“We could easily go through a 10-year stretch with not much happening. All it takes is five or 10 years before folks say, ‘What’s all this nonsense with global warming?'” Emanuel said. “We’re looking at very long-term trends, and that’s not the way most people are programmed to hear risks.”
In the short term, the state of the climate keeps getting worse. In terms of surface temperature, last year was Earth’s second-hottest on record after 2016, according to NASA. And Trenberth says it was the warmest year ever recorded for Earth’s oceans, which can be a better indicator of long-term changes since they absorb so much heat.
The scientific literature also continued to evolve over the last year — in some cases suggesting that worst-case climate scenarios are unlikely, but often concluding the situation is worse than previously understood. Recent research, for instance, has found the West Antarctic ice sheet could collapse this century, leading to 6 feet of average global sea-level rise, rather than 3 feet, by 2100. While scientists continue to debate whether that’s likely, even the possibility of 6 feet of sea-level rise is alarming.
“The critics, those who argue against taking action — you’ll often hear them say there’s uncertainty in the science, as if that’s a reason not to act,” said Michael Mann, a climate scientist at Penn State University. “But the irony is that as we learn more, we’re finding in many respects that the changes are happening faster than we expected, and they’re larger than we expected.”
Mann described the Trump administration as a “dream team of climate change denial.” Asked what he sees as Trump’s most damaging policy changes on climate, he pointed to the ongoing reversal of rules limiting carbon emissions, the rejection of the Paris climate deal, efforts to subsidize coal and a lack of support for renewable energy.
Mann said he’ll watch Trump’s State of the Union address “with an appropriate alcoholic beverage in my hand.”
“I don’t expect it to be good things he has to say, but the role of this particular effort is to fact-check and to truth-tell in the face of this ongoing assault,” Mann said.
David Bookbinder is less concerned than Mann and other climate advocates about the Trump administration’s policies. Bookbinder is chief counsel for the Niskanen Center, a libertarian think tank in Washington, D.C., that has encouraged Republicans to support a tax on carbon pollution as a conservative solution to climate change. He thinks hardly anything Trump does on climate will matter in the end, because it’s mostly happened through executive actions that can be reversed by a future president.
Asked what he’ll be paying attention to in 2018, Bookbinder pointed to the courts.
Many of the Trump administration’s regulatory rollbacks are facing legal challenges, but those battles could take several years to play out. Bookbinder is more interested in the lawsuits brought by a handful of cities against oil companies, arguing they knowingly polluted the climate and should have to pay for the property damage their pollution is causing. Bookbinder has consulted with lawyers working on some of those lawsuits.
“If Congress is doing nothing on climate change, and the executive branch not only is doing nothing but is denying it and rolling even the modest Obama measures back, this gives courts the opportunity to step in,” Bookbinder said. “That sets up a classic case: If Washington does nothing, and there’s an identifiable problem that is getting worse and is a property matter … that’s something the courts know how to deal with.”