Strict Climate Rules Only Cut Emissions When Institutions Are Strong Enough to Enforce Them

Why do some countries manage to bend their greenhouse gas emissions downward while others, despite passing ambitious environmental laws, see pollution continue to climb? A new study published in Discover Sustainability suggests that the answer lies not in the stringency of environmental policy alone, but in the quality of the institutions that implement and enforce it. Economist Carlos A. Carrasco of Universidad de Monterrey analyzed a panel of 40 countries over a quarter century and found that stringent environmental regulation is associated with lower emissions only when it is paired with high-quality governance. In countries where regulatory institutions lag behind, stricter policies on paper fail to translate into measurable reductions in the atmosphere.

The research addresses a long-standing puzzle in environmental economics. Decades of empirical work have examined whether environmental regulation reduces pollution, with results that often seem contradictory: some studies find strong effects, others find weak or negligible ones. Carrasco’s explanation is that much of this inconsistency may stem from treating policy stringency and institutional quality as separate factors, when in reality they operate jointly. A carbon tax or an emissions trading scheme is only as effective as the bureaucracy that designs it, monitors compliance, and penalizes violators. Where that machinery is weak, even well-designed instruments may exist mostly on paper.

To capture this interaction formally, the study constructs a composite index that combines two distinct data sources. The first is the OECD’s Environmental Policy Stringency index, which scores countries on the toughness of their market-based and non-market environmental instruments, including taxes, trading schemes, feed-in tariffs, emission limits, and technology-support policies. The second is the World Bank’s Worldwide Governance Indicators, specifically the regulatory quality dimension, which measures perceptions of the ability of a government to formulate and implement sound policies and regulations. By integrating the two, the author created a measure that reflects not just how demanding a country’s environmental rules are, but how capable its regulatory apparatus is of carrying them out.

The dataset covers 40 countries observed annually from 1996 to 2020, a period chosen because the governance indicators begin in 1996. Thirty-two of the countries are classified as high-income and eight as middle-income, allowing the study to test whether the policy-institution relationship differs across levels of economic development. The outcome variables are per capita greenhouse gas emissions and per capita carbon dioxide emissions, the latter offering a narrower focus on the fossil-fuel-driven component of a country’s climate footprint. This panel structure, with repeated observations of the same countries over time, gives the analysis far more statistical power than a snapshot comparison ever could.

Methodologically, the study is notable for the care it takes with the quirks of international panel data. Emissions data across countries exhibit cross-sectional dependence, meaning that shocks in one country, such as a global financial crisis or an oil price spike, ripple through others, violating the independence assumptions of simpler estimators. Carrasco therefore begins with Pesaran tests for cross-sectional dependence to characterize the problem. He then applies Dumitrescu-Hurlin panel causality tests to establish the direction of the relationship between regulation and emissions, an important safeguard against the possibility that causality runs the other way, with wealthy, low-emission countries simply being able to afford stricter rules.

The centerpiece of the analysis is a set of panel quantile regressions, implemented using the approaches developed by Canay and by Machado and Santos Silva. Unlike ordinary regression, which estimates the effect of a variable at the average of the outcome distribution, quantile regression estimates effects at different points along that distribution. This matters enormously for emissions research, because the countries and years sitting at the bottom of the emissions distribution, the cleanest performers, may respond to policy very differently from those at the median or the top, where the heaviest emitters are found. A policy that barely registers among already-efficient economies might have large effects among the biggest polluters, and only a distributional method can reveal that.

The results are striking in their pattern. For the full sample of 40 countries, and separately for the high-income group, the interaction between regulatory quality and environmental policy stringency shows a negative and statistically significant relationship with both greenhouse gas and carbon dioxide emissions per capita. In other words, stringent policies deliver emission reductions specifically where regulatory institutions are strong. Moreover, the effect is not uniform across the distribution: it is generally stronger at the median and upper quantiles of emissions, precisely where the largest emitters sit. This suggests that the combination of tough rules and capable institutions has its greatest leverage where the decarbonization challenge is hardest.

The story changes, however, when the analysis turns to the eight middle-income countries. For this group, no significant relationship emerges between the policy-institution interaction and emissions, at any point in the conditional distribution. The author interprets this as evidence that stricter environmental policies require stronger institutional capacity and enforcement mechanisms to produce measurable environmental outcomes. In middle-income settings, where regulatory agencies may be underfunded, monitoring may be incomplete, and enforcement may be inconsistent, increasing policy stringency alone does not appear to bend the emissions curve. The finding carries an uncomfortable implication for rapidly industrializing economies: passing tougher climate legislation without simultaneously investing in governance may yield little in the way of actual emission reductions.

The robustness of these conclusions was tested in several ways. The quantile estimates were replicated using alternative estimators, and the specifications were re-run with lagged explanatory variables to allow time for policies to take effect and to further address potential endogeneity concerns. Across these variations, the core pattern held: a significant negative association for the full sample and for high-income countries, concentrated at the median and upper quantiles, and no significant association for the middle-income group. This consistency across methods strengthens the case that the findings reflect a genuine structural relationship rather than an artifact of one particular statistical technique.

For policymakers, the study arrives at a moment when the gap between climate pledges and climate outcomes has become a central concern of global governance. Its message is twofold. First, in high-income countries, the evidence supports combining ambitious policy stringency with continued investment in regulatory quality, since the two reinforce each other and the payoff is largest among the heaviest emitters. Second, for middle-income countries, the results caution against a purely legislative approach to climate policy; building the administrative and enforcement capacity of environmental institutions may be a prerequisite for stringent rules to have any effect at all. As nations race to meet net-zero targets, the research suggests that the pen that signs the law matters less than the institutions that make it real.

Subject of Research: The joint effect of environmental policy stringency and regulatory quality on per capita greenhouse gas and CO2 emissions

Article Title: The joint impact of regulatory quality and policy stringency on greenhouse gas emissions in middle income and high income countries

Article References: Carrasco, C. A. (2026). The joint impact of regulatory quality and policy stringency on greenhouse gas emissions in middle income and high income countries. Discover Sustainability. https://doi.org/10.1007/s43621-026-04823-0

Image Credits: AI Generated

DOI: 10.1007/s43621-026-04823-0

Keywords: greenhouse gas emissions, environmental policy stringency, regulatory quality, panel quantile regression, climate policy, environmental economics, governance indicators, middle-income countries, high-income countries, CO2 emissions, Dumitrescu-Hurlin causality, cross-sectional dependence