As new reports indicate that Earth’s temperature will likely increase by two degrees Celsius by the end of the century, scientists and economists are once again urging the government to take immediate action to avoid the most devastating consequences of climate change.
The call for change comes at an unusual time in U.S. climate policy. President Donald Trump recently said the United States would withdraw from the Paris Agreement, and key officials in his administration continue to cast doubt on the evidence surrounding global warming.
Two studies this week from the University of Washington and the Cooperative Institute for Research in Environmental Studies confirmed previous findings on global warming. Former Vice President Al Gore also released a new documentary, An Inconvenient Sequel: Truth to Power, on August 4, to draw attention to the climate crisis.
Scientists and economists call on the federal government to implement carbon pricing and invest in carbon capture technologies to slow the process of global warming, and to establish adaptation measures to deal with inevitable temperature rises.
The reports, published in the scientific journal Nature Climate Change, build on the existing research on climate change. They demonstrate that “we have to move even faster,” said Michael Mehling, deputy director of the Center for Energy and Environmental Policy Research at the Massachusetts Institute of Technology. “The trend overall has been us underestimating climate change,” he said. “Each new study has been more and more sobering.”
One study used observational data to show that even if all greenhouse gas emissions were suddenly turned off today, Earth would still continue heating up about 1.3 degrees Celsius by the end of the century.
“The study tells us about the momentum of the climate system,” said Robert Pincus, one of the lead authors and a scientist at the Cooperative Institute for Research in Environmental Studies, a partnership of the University of Colorado–Boulder and the National Oceanic and Atmospheric Administration. “Even if you stop pushing on the climate system, it continues to change and warm.”
The study also shows a 13 percent chance that we are already committed to a 1.5-degree C increase by the end of the century. The 2016 Paris Agreement set a target for keeping temperature increases to 1.5 degrees or lower by 2100.
The other study from the University of Washington used statistical analysis to show only a 5 percent chance that Earth will warm 2 degrees or less by the end of the century.
“Our analysis shows that the goal of 2 degrees is very much a best-case scenario,” said lead author Adrian Raftery, a professor of statistics and sociology at the University of Washington, in a news release. “It is achievable, but only with major, sustained effort on all fronts over the next 80 years.”
The 2 degree threshold was first introduced by economist William Nordhaus in his 1977 paper, “Economic Growth and Climate: The Carbon Dioxide Problem,” and is commonly seen by scientists as the “line in the sand that we shouldn’t cross,” said Gilbert Metcalf, professor of economics at Tufts University, whose research centers on environmental economics.
Two degrees corresponds closely to when carbon dioxide levels have doubled from pre-industrial levels, explained Kevin Trenberth, senior scientist at the National Center for Atmospheric Research. The threshold marks the point “when disruptions from climate change become so large, they can’t just be brushed aside and adapted to in the normal way of things. The environmental pressures and the number of people that are affected by them become potentially overwhelming.”
Researchers say that slowing the warming process and adapting to the rise in temperature that has already happened are crucial. “The clear implication [of the studies] is we need to get to a zero-carbon economy as quickly as we can,” Metcalf said.
Carbon pricing – either in the form of a carbon tax or a cap on the total level of emissions allowed by each company––is an especially important tool.
“It’s the single most impactful policy we could put in place,” Metcalf stated. A carbon tax would increase the price of carbon-intensive goods to the point that consumers begin seeking out alternatives, he said. “A carbon tax is a way for the invisible hand to have a green thumb.”
But John Reilly, co-director of the Joint Program on the Science and Policy of Global Change at MIT, pointed out the difficulty involved in convincing governments to impose carbon prices at necessary levels. And without economic consequences, most industries continue emitting greenhouse gases.
“It’s hard for [companies] to imagine cutting their emissions by 80 percent by 2050 without the right economic incentives to do it,” Reilly said. “If companies want to do good, and do good, and go out of business, then all the efforts are wasted.”
Right now, few regions have implemented sufficiently high carbon prices, Mehling said, echoing Reilly. The International Monetary Fund has proposed a carbon price of $25 per ton, but carbon prices in most regions in the world with such prices are still far below that.
Investing in carbon capture and storage technologies is another, more aggressive, way to mitigate the effects of global warming, specialists say. Those technologies involve capturing and storing carbon from the atmosphere. But Mehling said carbon capture has not yet been deployed at scale anywhere.
Other possible solutions are in the works, notably with battery development, which is crucial to an “electric economy,” Gilbert said.
But given the inevitability of global warming, experts also advocate developing adaptation measures to deal with more extreme weather conditions including rising sea levels, stronger storms, greater risk of wildfires, and longer dry spells.