Government Policy To Cut Emissions Actually Works, Study Finds

Governments across the world have made various stabs at reducing emissions from greenhouse gases — and most of them have actually worked as advertised, according to a new study.

But importantly, the policies, while beneficial, fall well short of what's needed to cut emissions as much as needed.

"While existing efforts are vastly insufficient for limiting global warming to 1.5 degrees Celsius, three decades of mitigation policy have demonstrably lowered emissions and put us on a trajectory that makes reaching climate neutrality by mid-century a tenable goal," said Janna Hoppe, of ETH Zürich and lead-author of the study, according to a press release.

The study's findings may seem obvious, but there are long-standing arguments over whether government intervention to curb climate change-causing emissions really works, and whether a top-down regulatory approach or a more bottom-up, market-driven approach is best.

The authors examined results from more than 300 previously published studies on effects of greenhouse gas regulation around the world, and compared the rate of emissions over the last two decades with the attempts to reduce them — efforts that have included policies to reduce energy use, stop deforestation, build out solar and wind power and more.

They found that each year since the early 2000s, government policies helped avoid emission of between two and seven billion metric tons of carbon dioxide, or between 4% and 15% of the total, that would have been emitted otherwise. The results were published in Annual Reviews of Environment and Resources.

"Climate protection efforts have not been in vain," Hoppe said. "Policies have already led to a discernible reduction in greenhouse gas emissions."

Treaties Do Matter

International treaties play a particularly important role. The Kyoto Protocol, signed by 192 countries in 1997 (the U.S. signed but never ratified the treaty), helped cut emissions by 7% between 2008 and 2012. The Paris Agreement, signed in 2015, is too recent to have definitively made a difference, the authors said.

The results lend support to some recent projections of the effects of U.S. laws. According to Princeton University's REPEAT project, the combination of 2021's Bipartisan Infrastructure Law and 2022's Inflation Reduction Act will cut U.S. emissions by as much as 41% below 2005 levels by 2030 — or almost a billion tons of CO2 less than the country would emit if policies were frozen at the start of 2021.

"This exhaustive study shows that government policies and regulations can and have moved the needle on greenhouse gas emissions," said senior author Michael Grubb, of University College London, according to the release.

"Though global results have been modest so far, these path-leading successes only underline that more widespread and comprehensive policies can (and must) protect the climate."

Policies in place today — including those enshrined in countries' Paris Agreement commitments known as Nationally Determined Contributions — aren't enough to reach the global goal of keeping warming below 1.5 or even 2.0 degrees Celsius, experts have warned. During his speech to the United Nations General Assembly on Sept. 19, Secretary-General António Guterres made clear that it is governments — and in particular the governments of the richest, highest-emitting countries — that need to increase their policy ambition.

"I'm not sure all leaders are feeling that heat. Actions are falling abysmally short," he said. "G20 countries are responsible for 80% of greenhouse emissions. They must lead."