Climate policies are slippery things in a world where politics plays an outsized role in how countries decide to spend their human and monetary capital. In late August, a group of European scientists published a paper in the journal of Science, that used AI to look at more than 1500 policies world wide, and assessed which successfully reduced carbon emissions, and which were lip-service only.

The Report

The researchers used large amounts of climate data to find countries that had seen significant reductions in pollution. They narrowed their focus to countries that saw an average reduction in pollution of 19% or more, with a focus on building, electricity, transportation, and industry sectors for the 24 years between 1998 and 2022. Then, they overlaid those findings against the policies focused on climate change to figure out the success rate.

After combing through all that data, the findings were somewhat bleak with just 63 climate policies across 41 countries that made an actual impact on emissions reduction and pollution. Considering that the report looked at policies stretching across more than two decades, that's pretty dire. At the same time, the researchers pointed out that while the successful policy outcomes were limited, they did provide a blueprint of sorts for the kind of policies that work versus those that don't.

Why Climate Policies Failed

The report points out that many climate policies failed because they are not well-integrated with other economic and social policies. Researchers emphasized the importance of policy mixes that combine different instruments, such as regulations, carbon pricing, and targeted support for low-carbon technologies.

One of the most common reasons for policy failure was that they were not ambitious enough or implemented at a sufficient scale to drive significant emissions reductions. The research notes that this may have been due to political constraints, economic concerns, or the underestimation of the scale of change required.

Additionally, there were implementation gaps that impacted the success rate of the policies that the researchers looked at: Without enforcement or plans for implementation, the policies failed. Even well-designed policies can fail if there are gaps–or if, for example, one branch of the government begins to systematically dismantle the powers of others, as we’re seeing happen as a result of the recent Supreme Court rulings tearing down the enforcement abilities of the EPA and other agencies.

The research also showed that the timing and duration of policy implementation were crucial. Policies that were short-lived or inconsistently applied over time were less likely to succeed in driving lasting emissions reductions. Things like political turmoil, a global pandemic, and the resulting economic impacts all easily upended the best-laid plans of governments looking to impact climate change.

Finally, the study suggests that policies that work have to be leveraged in the right way for the context in which they’re applied. Policies that work well in one country or region may fail in another due to differences in economic structures, political systems, or social norms, all of which are constantly evolving and changing based on any number of mutable factors.

A Few Surprises

According to CNN reporting, the data that the researchers focused on led to some surprising discoveries, too. For one, Nicolas Koch, an environmental economist at the Mercator Research Institute on Global Commons and Climate Change and a researcher on the study told CNN that popular climate policies alone didn’t work.

When combined with other carrot-and-stick tools that many governments use to affect widespread change, including incentives and taxes, the policies were successful. Koch told CNN, “The surprising finding, really, is that we never detect successful large emission reductions if these policy tools are used alone.”Koch continued, telling CNN that bans were “not credible if the phase-out plan is just out there,” meaning that in order for climate policies to be successful, other additional measures are necessary to push a country in a specific direction.

Carrots and Sticks

Those carrots and sticks take many forms, but CNN points out two examples of success stories that employed both policy tools, incentives, and taxation to be effective.

For example, the US significantly cut its pollution in 2008 when fuel-efficiency rules for the transportation sector (specifically vehicles) were revised and when a number of tax breaks went into effect for lower-carbon vehicles.

In the UK, policy leaders focused their climate change policies on reducing the use of coal for electricity in 2015 and 2016. The country also implemented a more stringent set of air pollution standards, offered subsidies for renewable energy generation, and set a carbon minimum price for UK power companies. As it turns out, the tool that affected the most change (when combined with policy programs) in the countries with the most successful pollution reduction policies was taxes.

The Role of Carbon Border Adjustment Mechanisms

The problem with taxation as a climate change tool is that the payment burden generally falls on those who are the least able to carry the financial burden, as the researchers note. That’s far from ideal when it comes to making policy changes that work for the entire country.

One such option might take the form of what the EU has done with its Carbon Border Adjustment Mechanism, which essentially places an additional fee on products that enter or exit the EU based on the volume of greenhouse gases emitted during production. It’s essentially a carbon border tax, with those products that emit more carbon becoming more expensive. It's not a perfect model, as MIT points out, but it does seem to have some impact, according to the report.

While there are a handful of bills moving through Congress in the US that would implement a similar system, they're still relatively unpopular. Should the former president and current Republican nominee for president, Donald Trump, win the election in November, there's no question that all hopes for these kinds of policies and bills would be dead in the water. Trump and his Project 2025 plans (even though he has tried to distance himself from them) would dash any hopes of the US making meaningful progress through policy, taxation, or other tools in the fight against climate change.

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