Assessment of climate policy measures over two decades reveals that many have failed to achieve the necessary emissions reductions

An international research team has released the first comprehensive global assessment of 1,500 climate policy measures taken by 41 countries across six continents.

Published in the journal ScienceThis study provides a detailed analysis of the impact of the wide range of climate policy measures implemented over the past two decades. The results reveal a sobering reality: many policy measures have failed to achieve the necessary scale of emissions reductions.

Only 63 cases of effective climate policies were identified, each resulting in an average reduction in emissions of 19%. The main characteristic of these success stories is the inclusion of tax and price incentives in well-designed policy mixes.

Much of the debate on climate policy focuses on which climate policy instruments work to reduce emissions and which do not. Yet previous assessments have focused on a limited number of flagship measures, neglecting hundreds of other measures.

This new study, conducted by researchers from the Potsdam Institute for Climate Impact Research (PIK) and the Mercator Research Institute on Global Commons and Climate Change (MCC) in collaboration with experts from the University of Oxford, Victoria University and the Organisation for Economic Co-operation and Development (OECD), aims to fill this gap.

An accompanying interactive website, the Climate Policy Explorer, provides a comprehensive overview of the results, analyses and methods, and is publicly available.

“We systematically evaluated policy measures that have rarely been studied until now, providing new insights into well-designed combinations of complementary policy instruments. We draw best practices from this – for the buildings, electricity, industry and transport sectors, both in industrialized countries and in often neglected developing countries,” explains lead author Nicolas Koch of PIK and MCC.

“Our results demonstrate that more measures do not necessarily translate into better results. However, it is essential to find the right combination of measures. For example, subsidies or regulations alone are not enough; only in combination with price-based instruments, such as carbon and energy taxes, can they lead to substantial emission reductions.”

The study highlights concrete examples to illustrate this point. The researchers show, for example, that banning coal-fired power stations or cars with combustion engines does not result in a major reduction in emissions when implemented alone. Successful cases only occur in combination with tax or price incentives, as shown in the case of the United Kingdom for coal-fired electricity generation or Norway for cars.

In-depth analysis of 1,500 policy measures and 63 success stories

The researchers assessed 1,500 policy interventions implemented between 1998 and 2022, covering the full range of climate policy instruments, from energy-related building codes to subsidies for the purchase of climate-friendly products and carbon taxes.

Using a new OECD database, which represents the most comprehensive inventory of global climate policies to date, and an innovative approach combining machine learning methods with established statistical analyses, the team conducted a detailed impact assessment of these policies, identifying measures that have achieved large-scale emissions reductions.

“Although it remains difficult to precisely disentangle the effects of individual measures within a policy mix, our 63 success cases provide systematic insights into effective policy combinations and show how well-designed policy mixes depend on the sectors and development level of countries,” notes lead author Annika Stechemesser of PIK.

“This knowledge is essential to support policy makers and society in the transition to climate neutrality.”

Climate Policy Explorer: A comprehensive resource

The interactive Climate Policy Explorer provides detailed information on specific countries, sectors and policy measures. In the industrial sector, for example, China’s pilot emissions trading schemes have achieved significant emissions reductions after a few years, thanks to reduced fossil fuel subsidies and stronger financial incentives for energy efficiency.

In the electricity sector, the UK has managed to significantly reduce its emissions through a minimum carbon price, subsidies for renewable energy and a plan to phase out coal.

The United States is an example of significant emissions reductions in the transport sector, resulting from a combination of tax incentives and subsidies for low-emission vehicles and CO emissions.₂ Energy efficiency standards. The reform of the ecotax and the introduction of a toll for heavy goods vehicles in Germany are another notable success in the transport sector.