The science behind decarbonization

By the start of a virtual climate summit on Earth Day, April 22, the Biden administration is expected to outline a new target for cutting U.S. greenhouse gas emissions this decade.

Already, climate change has hurt farm productivity, caused tens of billions of dollars in flood damages in the U.S. alone, and increased the the risk of longer, more dangerous wildfire seasons in California. The goal of deep emission cuts is to slow the world’s advancement toward a dangerous temperature threshold beyond which climate impacts are likely to become more severe and widespread, including droughts, extreme heatwaves and floods.

In the 2015 Paris Climate Agreement, nearly 200 nations committed to holding this century’s average temperature to well below 2°C and to “pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change.”

Current commitments fall short of that aspirational goal. A 2018 paper led by Stanford climate scientist Noah Diffenbaugh found the gap could considerably increase the likelihood of extreme weather. Other research suggests failing to meet the accord’s climate mitigation goals could cost the global economy tens of trillions of dollars. The lead study author, environmental economist Marshall Burke, has said, “Over the past century we have already experienced a 1-degree increase in global temperature, so achieving the ambitious targets laid out in the Paris Agreement will not be easy or cheap."

The current U.S. emission pledge, made under former President Barack Obama, targets cuts of 26 to 28 percent below 2005 levels by 2025. In November 2021, countries participating in major UN climate talks (COP26) in Glasgow, Scotland, will be expected to announce new, more ambitious plans for slashing their emissions over the next decade.

More than 300 businesses and investors have urged the Biden administration to commit to reducing greenhouse gas emissions to at least 50 percent below 2005 levels by 2030, “in pursuit of reaching net-zero emissions by 2050.” European lawmakers, trade unions, businesses and environmental groups have also called for the U.S. – the world’s largest historical carbon emitter – to cut emissions at least 50 percent below 2005 levels this decade.

Halving the nation’s emissions will require significant changes. This collection covers how scientists are evaluating the stakes of emission cuts, enabling better carbon accounting, predicting the consequences of future emission pathways and mapping out viable solutions.

Scroll down for research news and insights spanning emission targets; the role of renewable energy and grid storage; prospects for adaptation and a more equitable recovery; the future of fossil fuels and carbon capture; the promise and limits of natural climate solutions such as reforestation – and more.

Last updated: February 4, 2022'