Study shows which climate policies actually work

With time running out to avoid catastrophic levels of climate change, a comprehensive new study has identified which government policies actually help to rein in planet-heating emissions.

Aided by machine learning tools, researchers at the Potsdam Institute for Climate Impact Research and other organisations looked at 1,500 climate policies implemented worldwide over the past 25 years — and found there were only 63 successful ones.

“Our insights on effective but rarely studied policy combinations highlight the important role of price-based instruments in well-designed policy mixes and the policy efforts necessary for closing the emissions gap,” reads the study, which was published in Science.

As an example, in the UK’s electricity sector, the introduction of a minimum price on carbon in 2013, alongside other measures such as stricter air pollution standards and renewable energy feed-in tariffs and auctions, yielded substantial emissions cuts.

In China’s industrial sector, the imposition of carbon pricing, combined with a reduction in fossil fuel subsidies and the strengthening of financing mechanisms for energy efficiency investments, generated similar results.

In Norway, meanwhile, transport emissions were significantly reduced thanks to a combination of rail subsidies, electric vehicle subsidies, and higher taxes on combustion-engine cars.

“In most cases, we found that effect sizes are larger if a policy instrument is part of a mix, rather than implemented alone,” the authors write. However, taxation-based policy instruments are the one exception — they can deliver large emission reductions in all sectors without supporting measures.

Lead author Nicolas Koch said the study demonstrated that “more policies do not necessarily equate to better outcomes.”

“Instead, the right mix of measures is crucial. For example, subsidies or regulations alone are insufficient; only in combination with price-based instruments, such as carbon and energy taxes, can they deliver substantial emission reductions.”

Additionally, the success of a policy mix depends on the sector it’s aimed at and the development level of the country, notes lead author Annika Stechemesser.

The different policy combinations behind sharp falls in emissions have been loaded onto an interactive online dashboard to assist policymakers.