Systematic review and meta-analysis of ex-post evaluations on the effectiveness of carbon pricing
(2024)
Today, more than 70 carbon pricing schemes have been implemented around the globe, but their contributions to emissions reductions remains a subject of heated debate in science and policy. Here we assess the effectiveness of carbon pricing in reducing emissions using a rigorous, machine-learning assisted systematic review and meta-analysis. Based on 483 effect sizes extracted from 80 causal ex-post evaluations across 21 carbon pricing schemes, we find that introducing a carbon price has yielded immediate and substantial emission reductions for at least 17 of these policies, despite the low level of prices in most instances. Statistically significant emissions reductions range between –5% to –21% across the schemes (–4% to –15% after correcting for publication bias). Our study highlights critical evidence gaps with regard to dozens of unevaluated carbon pricing schemes and the price elasticity of emissions reductions. More rigorous synthesis of carbon pricing and other climate policies is required across a range of outcomes to advance our understanding of “what works” and accelerate learning on climate solutions in science and policy.
Steuern und Abgaben auf Produkte oder Verbrauch mit gesellschaftlichen Folgekosten (externe Kosten) – sogenannte Pigou- oder Lenkungssteuern – sind ein gesellschaftliches „Win-Win-Instrument“. Sie verbessern die Wohlfahrt und schützen gleichzeitig die Umwelt und das Klima. Dies wird erreicht, indem umweltschädigende Aktivitäten einen Preis bekommen, der möglichst exakt der Höhe des Schadens entspricht. Eine konsequente Bepreisung der externen Kosten nach diesem Prinzip könnte in Deutschland erhebliche zusätzliche Einnahmen erbringen: Basierend auf bisherigen Studien zu externen Kosten wären zusätzliche Einnahmen in der Größenordnung von 348 bis 564 Milliarden Euro pro Jahr (44 bis 71 Prozent der gesamten Steuereinnahmen) möglich. Die Autoren warnen allerdings, dass die Bezifferung der externen Kosten mit erheblichen Unsicherheiten verbunden ist. Damit Lenkungssteuern und -abgaben ihre positiven Lenkungs- und Wohlstandseffekte voll entfalten können, seien zudem institutionelle Reformen notwendig.
Assessing Climate Policy Instrument Pathways: An Application to the German Light Duty Vehicle Sector
(2022)
Klimaschutz und Verkehr: Zielerreichung nur mit unbequemen Maßnahmen möglich. Ariadne-Analyse
(2021)
Die Klimaschutzziele für das Jahr 2030 sind im Verkehrssektor nur mit starken zusätzlichen Treibhausgasreduktionen erreichbar. Die beschlossenen Maßnahmen können laut gegenwärtigen Projektionen nur einen Bruchteil jener Emissionen reduzieren, welche für die Erreichung der Klimaschutzziele im Verkehrssektor notwendig wären. Um die politische Umsetzbarkeit zusätzlicher Klimaschutzmaßnahmen zu erörtern, analysieren wir die Emissionsminderungswirkung und die Bevölkerungsakzeptanz von 14 möglichen Maßnahmen, basierend auf Drittstudien und eigenen Erhebungen. Wir zeigen, dass die wirkungsstärksten Maßnahmen tendenziell eine geringe Zustimmung in der Bevölkerung erfahren, wobei die Lastenverteilung keinen sichtbaren Einfluss auf die Bevölkerungsakzeptanz hat. Maßnahmen, die in der Bevölkerung mehrheitlich unterstützt werden, führen nach gegenwärtigen Projektionen nur zu geringen Treibhausgasreduktionen, so dass die Erreichung der Klimaziele 2030 ohne kontroverse Maßnahmen wie höhere CO2-Preise oder einer flächendeckenden Maut unwahrscheinlich ist. Um die Befürwortung von gegenwärtig kontroversen Maßnahmen zu erhöhen, ist es notwendig, sichtbare Rückverteilungsmechanismen zu etablieren, Maßnahmen durch gruppenspezifische Kommunikation zu begleiten und die Einführung von Politikinstrumenten strategisch zu sequenzieren.
Despite the importance of evaluating all mitigation options to inform policy decisions addressing climate change, a comprehensive analysis of household-scale interventions and their emissions reduction potential is missing. Here, we address this gap for interventions aimed at changing individual households’ use of existing equipment, such as monetary incentives or feedback. We have performed a machine learning-assisted systematic review and meta-analysis to comparatively assess the effectiveness of these interventions in reducing energy demand in residential buildings. We extracted 360 individual effect sizes from 122 studies representing trials in 25 countries. Our meta-regression confirms that both monetary and non-monetary interventions reduce the energy consumption of households, but monetary incentives, of the sizes reported in the literature, tend to show on average a more pronounced effect. Deploying the right combinations of interventions increases the overall effectiveness. We have estimated a global carbon emissions reduction potential of 0.35 GtCO2 yr−1, although deploying the most effective packages of interventions could result in greater reduction. While modest, this potential should be viewed in conjunction with the need for de-risking mitigation pathways with energy-demand reductions.
Despite the importance of evaluating all mitigation options so as to inform policy decisions addressing climate change, a systematic analysis of household-scale interventions to reduce carbon emissions is missing. Here, we address this gap through a state-of-the-art machine-learning assisted meta-analysis to comparatively assess the effectiveness of a range of monetary and behavioral interventions in energy demand of residential buildings. We identify 122 studies and extract 360 effect sizes representing trials on 1.2 million households in 25 countries. We find that all the studied interventions reduce energy consumption of households. Our meta-regression evidences that monetary incentives are on an average more effective than behavioral interventions, but deploying the right combinations of interventions together can increase overall effectiveness. We estimate global cumulative emissions reduction of 8.64 Gt CO2 by 2040, though deploying the most effective packages and interventions could result in greater reduction. While modest, this potential should be viewed in conjunction with the need for de-risking mitigation with energy demand reductions and realizing substantial co-benefits.
Carbon pricing is essential to achieve a reduction in global CO2 emissions. A carbon price can either be set directly via a carbon tax (price control) or be achieved through a cap-and-trade system (quantity control). While there has been much debate about the relative merits of each approach, cap-and-trade systems have been favoured in the political arena. In principle, they offer the most straightforward way to achieve a country’s emission reduction target by simply setting the cap at the remaining emission budget. Existing emissions trading schemes (ETSs) can be found in Europe, California and Québec, for example.
The performance of the European Union (EU) Emissions Trading System (ETS) and other cap-and-trade schemes has been under scrutiny because of their inability to create a stable price for greenhouse gas emissions. This article seeks to inform the often confusing debate about the economic performance of cap-and-trade systems over time, with a focus on the EU ETS. Based on a simple intertemporal framework of emissions trading and a review of the literature, we show that different frameworks and notions of efficiency result in both different assessments of performance and different recommended strategies for improving performance. More specifically, we argue that if cap-and-trade systems have temporal flexibility (i.e., they include banking and borrowing of emissions allowances), it can be highly misleading to base the economic assessment on short-term efficiency. We seek to draw attention to the concept of long-term economic performance, which takes into account the intertemporal nature of emissions trading systems. In particular, we identify market and government distortions (e.g., myopia, lack of policy credibility, excessive discounting) that may depress allowance prices and hamper intertemporal efficiency. We then examine whether the recently adopted Market Stability Reserve and the alternative price collar are likely to address these distortions.