WASHINGTON (AP) — To understand what really works as countries try to combat climate change, researchers examined 1,500 ways countries have tried to reduce heat-trapping gases. Their answer: Many have failed. And success often means someone has to pay a price, whether at the gas station or elsewhere.
According to a new study published Thursday in the journal Science, researchers found policies that led to significant reductions in carbon pollution in just 63 cases since 1998.
For example, steps to phase out fossil fuel use and gasoline-powered engines don’t work alone, but are more successful when combined with some sort of energy tax or cost-surcharge system, the study authors found in a comprehensive analysis of global emissions, climate policies and laws.
“If you want to reduce emissions, a key ingredient is to have pricing in the policy mix,” said study co-author Nicolas Koch, a climate economist at the Potsdam Institute for Climate Impact Research in Germany. “If subsidies and regulations come alone or in combination, you won’t see big emissions reductions. But when price instruments like a carbon energy tax come into the mix, they will deliver those big emissions reductions.”
The research also found that methods that work in rich countries do not always work in developing countries.
But some foreign policy experts, climate scientists and economists who praised the study said it showed the power of the budget in combating climate change, something economists have always suspected.
“We’re not going to solve the climate problem in richer countries until the polluter pays,” says Rob Jackson, a Stanford University climate scientist and author of Clear Blue Sky. “Other policies help, but they nibble at the edges.”
“Carbon pricing places responsibility on the products and owners that cause the climate crisis,” Jackson said in an email.
Koch said a great example of what has worked in the U.K. power sector was that country, which implemented a mix of 11 different policies starting in 2012, including a coal phase-out and a pricing scheme that included emissions trading, which he said had cut emissions by almost half — “a huge impact.”
Of the 63 success stories, the largest reductions were seen in South Africa’s construction sector, where emissions were reduced by around 54% through a combination of regulations, subsidies and labelling of appliances.
The only success story in the United States was in transportation, where emissions fell 8% from 2005 to 2011 thanks to a mix of fuel standards and subsidies that coincided with regulation.
But even policy tools that appear to be working barely make a dent in ever-increasing carbon dioxide emissions. Overall, the 63 successful examples of climate policies have reduced between 600 million and 1.8 billion tons of the heat-trapping gas, the study found. Last year, the world spewed out 36.8 billion tons of carbon dioxide burning fossil fuels and making cement.
The study found that if every major country somehow learned the lesson of this analysis and enacted the policies that worked best, it would shrink the United Nations’ “emissions gap” of 23 billion metric tons of all greenhouse gases by only about 26%. That’s the difference between the amount of carbon the world is prepared to release into the air by 2030 and the amount that would keep warming at or below internationally accepted levels.
“This fundamentally shows that we need to do a better job,” said Koch, who heads the policy evaluation laboratory at the Mercator Research Institute in Berlin.
“The world really needs to step up, go into emergency mode and make the impossible possible,” said Niklas Hohne of Germany’s New Climate Institute, who was not involved in the study.
Koch and his team examined emissions and efforts to reduce them in 41 countries between 1998 and 2022—so that does not include the nearly $400 billion U.S. climate spending package that was considered the cornerstone of President Joe Biden’s environmental policy two years ago—and recorded 1,500 different policy actions. They grouped the policies into four broad categories—pricing, regulation, subsidies and information—and analyzed four separate sectors of the economy: electricity, transportation, buildings and industry.
In what Koch calls a “reverse causal approach,” the team looked for emissions declines of 5% or more in different sectors of countries’ economies and then used observations and machine learning to figure out what caused them. The researchers compared emissions with similar countries as control groups and took into account weather and other factors, Koch said.
The team created a statistically transparent approach that others can use to update or reproduce, including an interactive website where users can select countries and economic sectors to see what works. And it could eventually be applied to the 2022 Biden climate package, he said. That package was heavy on subsidies.
Politicians are finding it easier to pass policies that support and encourage low-carbon technologies, said John Sterman, a management professor at the MIT Sloan Sustainability Institute who was not involved in the research. He said that’s not enough.
“It is also necessary to discourage fossil fuels by keeping their prices close to their full costs, including the cost of climate damage,” he said.
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