In order to reduce greenhouse gas emissions and thus curb the progression of climate change, governments around the world have taken numerous measures in recent decades. Researchers have now examined which of these really help. According to them, only 63 of the 1,500 instruments examined contribute effectively to climate protection. Their positive effect on reducing CO2 emissions is based less on the individual measures than on a combination of measures adapted to the circumstances and economy of the respective country, as the evaluation showed.
Climate change has long been a reality – what scientists predicted decades ago has become increasingly visible and noticeable in recent years. Since then, politicians have paid more attention to climate protection. In order to at least limit the extent of global warming, governments around the world have already implemented thousands of climate policy measures over the past two decades. But which of these climate policies are effective on a large scale? And which are the most effective in reducing greenhouse gas emissions?
Balance of global climate policy
A team led by Annika Stechemesser from the Potsdam Institute for Climate Impact Research (PIK) has now investigated this. To do this, the climate researchers examined the impact of 1,500 climate policy measures that were introduced in 41 countries between 1998 and 2022. The data came from the Organisation for Economic Co-operation and Development (OECD) and includes countries that together emit around 80 percent of global emissions. To evaluate the data, the researchers used an advanced computer analysis based on machine learning. This allowed them to statistically evaluate the effect a measure had on CO2 emissions, either individually or in conjunction with other instruments, in different regions and over different periods of time.
The analysis showed that the countries examined had implemented or tightened an average of four to eight different climate protection measures by 2022. However, the vast majority of these measures have so far contributed little to climate protection, as the team reports. But 63 of the 1,500 measures can be considered a real success story: These regulations resulted in a reduction in global CO2 emissions of between 0.6 and 1.8 billion tons – an average of around 20 percent in their area, as Stechemesser and her colleagues found.
In Norway, for example, new cars with combustion engines were recently banned and tax incentives for the purchase of electric cars were introduced. According to the study, a German success story in the transport sector is the eco-tax reform for energy consumption introduced in 1999 and the truck toll introduced in 2005, both accompanied by investments in the railways. In 2013, Great Britain decided to close down coal-fired power plants and at the same time promoted renewable energies and introduced a minimum price for CO2. China has also successfully introduced pilot projects for emissions trading. In addition, the country has almost simultaneously reduced its subsidies for fossil fuels and increased financial incentives for energy-efficient business, thus also reducing its emissions. Argentina has recently re-regulated its construction industry and introduced a CO2 price.
When do political instruments have an impact on the climate?
But why were these 63 climate policy measures so much more effective than the others? Most of the positive effects on CO2 emissions are due to synergy effects that have largely been ignored so far, as the team reports. The effect is not only based on the individual measures, but above all on a mixture of different practices that intervene in the economic market and complement each other. They regulate prices in industry and the electricity sector, set financial incentives or regulate transport and construction. A clever and individual combination of such interventions depending on the economic sector usually contributes more effectively to climate protection than individual instruments, as the evaluation showed.
“Our results show that more policy does not necessarily lead to better results. Rather, the right mix of measures is crucial,” explains co-author Nicolas Koch from PIK. Costs are also crucial. “Subsidies or regulations alone are not enough; only in combination with price-based instruments such as CO2 and energy taxes can they lead to substantial emission reductions.” However, it also showed that pricing industrial processes was less effective in developing countries than in industrialized countries. This suggests that subsidies and regulations should be used first to intervene in the market in a way that has an impact on the climate before additional pricing policies are implemented, according to the team.
Further efforts needed
Despite their success, the few measures that have been effective so far are far from sufficient to achieve the Paris climate target. According to the researchers, these successful recipes could and should be expanded and extended to other countries in order to have an even greater impact. However, significantly more effort is needed in addition, say Stechemesser and her colleagues. “Our results offer a clear but sobering perspective on the political efforts required to close the remaining emissions gap of 23 billion tons of carbon dioxide (CO2 equivalents) by 2030,” write the climate researchers. “This knowledge is crucial to support politics and society in the transition to climate neutrality,” says Stechemesser.
Source: Annika Stechemesser (Potsdam Institute for Climate Impact Research) et al.; Science, doi: 10.1126/science.adl6547; Climate Policy Explorer