Over the past two decades, the landscape of global climate policy has undergone a significant transformation. The Organization for Economic Co-operation and Development (OECD) data from 1998 to 2022 paints a clear picture of this evolution, highlighting the growing number of policies and the diverse approaches countries are taking to address climate change.
From 1998 to 2022, the number of climate policies adopted worldwide steadily increased. By 2022, countries implemented an average of four to eight new policies or policy tightenings yearly. These policies spanned various instruments, including command-and-control measures like emission standards and technology mandates, which emerged as the most frequently used tools across most sectors. Market-based policies, such as carbon pricing, were less widespread, with only 116 cases globally, predominantly in developed economies and the transport sector.
The diversity in policy instruments reflects different countries' varying economic, social, and political contexts. While developed economies have leaned more towards market-based solutions, such as subsidies and emissions trading schemes, developing economies have often relied on regulatory approaches. This variation underscores the need for tailored strategies that align with each country’s unique circumstances.
Despite the proliferation of climate policies, their effectiveness in reducing emissions has been uneven. Through a machine learning-based analysis, researchers identified only 69 significant emission reductions, or “breaks,” out of approximately 1,500 policy adoptions and tightenings. These breaks were most commonly observed in the building sector, followed by transport, industry, and electricity.
Interestingly, most of these breaks occurred in developed economies, with 48 instances compared to 21 in developing or transitioning economies. This disparity suggests that while developing nations adopt climate policies, they may face greater challenges translating these efforts into substantial emission reductions.
The timing of these emission breaks often coincided with the implementation or tightening of climate policies, indicating a direct link between policy action and emission outcomes. On average, these breaks resulted in a 19.4% reduction in emissions, with particularly strong impacts on the buildings and electricity sectors.
One of the key insights from this analysis is the importance of policy mixes—combinations of different policy instruments—over standalone measures. The data revealed that effect sizes were generally larger when policies were implemented as a mix. For example, policy mixes that included pricing mechanisms, such as carbon taxes or emission trading, were consistently associated with significant emission reductions in the electricity sector.
This finding suggests that non-price-based policies, such as subsidies and regulations, often require complementary instruments to achieve their full potential. In contrast, taxation emerged as the most effective standalone policy, particularly in developed economies. However, even taxation was more effective when combined with other measures, reinforcing the need for a comprehensive approach to climate policy.
The study also uncovered sector-specific trends in policy effectiveness. In developed economies, pricing mechanisms were particularly successful in the transport sector, accounting for 20% of all successful interventions. Subsidies were most effective when combined with pricing, highlighting the complementary nature of these instruments. Regulation was the most powerful tool in developing economies, especially with subsidies and pricing.
The electricity sector in developing economies presented a unique case where subsidies alone were the most effective policy tool. This starkly contrasts the findings in developed economies, where subsidies were only effective when part of a mix. This highlights the varying dynamics across regions and the importance of context-specific policy design.
The global experience with climate policies over the past two decades provides valuable lessons for the future. While adopting climate policies has increased significantly, their effectiveness in reducing emissions has been uneven. The evidence suggests that policy mixes, particularly those that include pricing mechanisms, are more likely to result in substantial emission reductions than standalone measures.
As countries continue to grapple with the challenges of climate change, they must consider these insights when designing their climate policies. By adopting a mix of complementary policy instruments tailored to their specific contexts, countries can enhance the effectiveness of their climate actions and make meaningful progress toward reducing global emissions. The path forward is clear: it requires more policies and smarter, more integrated approaches that leverage the strengths of different instruments to achieve the greatest impact.
