Last chance to curb greenhouse gas emissions and climate change to limit catastrophic effects, international panel says

The world faces a final opportunity to limit the extreme impacts of global warming, a key international science panel warned on Oct. 8 in South Korea. Successful intervention would require, however, “rapid, far-reaching and unprecedented changes in all aspects of society,” the panel said.

Global warming has already reached at least a 1 °C rise since the Industrial Revolution. That rise is driven by emissions of greenhouse gases, primarily carbon dioxide and methane, from human activity. Now a new report by the Intergovernmental Panel on Climate Change (IPCC) says the world is on a path to have its temperature rise 1.5 °C by 2030 and 2 °C by 2050 if people do not take swift action. This increase in global temperatures would have catastrophic effects, the report says.

A series of international agreements, stretching back to 2010, held the goal of limiting the rise of temperature due to global warming to 1.5 °C. This study, however, shows that goal is now unattainable without sweeping changes affecting land use, energy, industry, buildings, and transportation.

“Limiting warming to 1.5 °C is possible within the laws of chemistry and physics but doing so would require unprecedented changes,” said Jim Skea, cochair of an IPCC working group that prepared the report and a professor at Imperial College London’s Centre for Environmental Policy. Skea underscored an important role for scientists, particularly chemists, in reaching the needed reductions.

The IPCC report calls for greatly enhancing energy efficiency; expanding wind, solar, and nuclear energy production and energy storage; shifting from fossil- to electric-fueled vehicles; implementing carbon capture and storage; and ending coal use. Also needed are sweeping changes in agriculture, including implementing sustainable land-use practices, restoring ecosystems, and transitioning to less resource-intensive diets.

To curb global warming, by 2030 global net human-caused emissions of CO₂ must fall by about 45% from 2010 levels and reach a net zero emissions level around 2050. These figures mean that any remaining emissions would need to be balanced by removing CO₂ from the air through reforestation, land restoration, soil carbon sequestration, and direct air carbon capture and storage—an untried technology.

The report predicts grave climate change effects if people do not take action; it points to sea-level rise, coral-reef destruction, flooding, wildfires, extreme weather events, and famine. The impacts are particularly hard on the world’s poor.

The report reflects the fact that the nations of the world are already failing to make reductions they committed to in the 2015 Paris Agreement. The worst offender is the U.S., which plans to exit the agreement and has plunged ahead with plans to increase coal use and oil production. The U.S. is the world’s second-largest carbon emitter. But even if nations adhere to their Paris pledges, the expected temperature increase is 3 °C by the century’s end, the report says.

Governments attempting to implement the Paris Agreement asked the IPCC to create the report. At a press briefing, the IPCC panel members were repeatedly asked what governments should do. Deciding government actions was not their role, they answered, noting policy responses will be discussed in December at the Katowice Climate Change Conference in Poland.

Those policy responses will be informed, at least in part, by the work of William D. Nordhaus of Yale University and Paul M. Romer of New York University, who will share the 2018 Nobel Prize in economics.

Nordhaus developed a quantitative model integrating CO₂ emissions, climate, and economic growth. His results suggest that global carbon taxes would be the most efficient method to curb greenhouse gas emissions.

Romer studies how innovation drives economic growth. His work shows that some government policies, such as research and development subsidies and patent regulation, are necessary to encourage new ideas and long-term growth.

Nordhaus and Romer have provided “fundamental insights into the causes and consequences of technological innovation and climate change,” the Nobel Prize announcement says. “Their findings have brought us considerably closer to answering the question of how we can achieve sustained and sustainable global economic growth.”