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This paper reviews efforts to meet the climate goals of the Paris Agreement: to limit global warming to well below 2°C and ideally to 1.5°C above pre-industrial levels. The paper shows how the likelihood of breaching these thresholds presents the need for additional measures, in mitigation and intervention. Three climate actions are discussed: emissions reduction, greenhouse gas removal, and solar radiation modification. These actions differ in timescale and current state of knowledge. Progress must intensify if they are to aid in securing a safe and stable climate for future generations.
Technical summary
Current assessments of global greenhouse gas emissions suggest the Paris Agreement temperature thresholds of 1.5°C and 2°C warming above pre-industrial levels could be breached. The impacts on humans and ecosystems could be severe. Global trends suggest a prolonged reliance on fossil fuels. Additional measures to limit global warming are therefore needed. Here, we review three climate actions: emissions reduction, greenhouse gas removal (GGR), and solar radiation modification (SRM). Emissions reduction requires shifting energy production away from fossil fuels (the primary contribution of anthropogenic greenhouse gas emissions), reducing energy use in key sectors, and optimising land management. GGR efforts must scale sustainably in the near term. The scale-up of novel methods is constrained by economic and technological challenges and, in some cases, limited knowledge. SRM has received growing attention, given the immediate impacts of global warming and the protracted timescales of emissions reduction and GGR. Robust research and governance frameworks are needed to assess the risks posed by SRM, alongside the risks of forgoing SRM. These three actions could enable society to fulfil the Paris Agreement, limiting global warming and its impacts while atmospheric greenhouse gas concentrations are reduced to sustainable levels.
Social media summary
The progress of climate mitigation and intervention towards securing a sustainable future in a safe and stable climate.
Amidst the global digital transformation and the expanding IT sector, particularly in Ukraine, it is essential to examine how digitalization affects structural shifts within the national economy. This study aims to analyze the impact of digitalization on the growth of Ukraine’s IT sector, focusing on comparing the economic metrics of freelancing and outsourcing and providing strategic recommendations to enhance entrepreneurial activity in this area. During the research, the methods of expert evaluations, economic-mathematical modelling, comparative analysis, and statistical data analysis were used. The research revealed that digitalization significantly influences structural changes in the national economy, particularly through the advancement of the IT sector. It was established that outsourcing has significant advantages compared to freelancing in terms of such indicators as the share of the GDP of the IT sector and the volume of exports of IT services. By analyzing the economic indicators of freelancing and outsourcing, specific recommendations were developed for the continued growth of Ukraine’s IT sector, aimed at boosting entrepreneurial activity and creating new job opportunities. The key factors influencing IT specialists’ employment choices were summarized, which is crucial for the continued development of the national economy in the context of digitalization. The practical value of this research is that its findings can be utilized to enhance Ukraine’s IT sector, particularly by backing outsourcing businesses and promoting the expansion of freelance platforms.
For all their differences, the two rival theories of human behavior have many unfortunate similarities. Standard rational choice theory posits that individuals use rational techniques to pick ends that meet their set of private preferences. Modern theories of behavioral economics point to systematic deviations from those principles. Both approaches assume that all preferences are individually based. However, the evolutionary principle of inclusive fitness insists that in family situations, it is the welfare of the unit, not of any of single individual, that explains various forms of natural love and affection that arise because of the interdependence of − and the redistribution of − wealth it requires. Likewise, both standard theories ignore variations in tastes and in competence levels that allow for gains from trade across competence levels. This paper then reinterprets the common treatment of nudges and the various legal doctrines dealing with disabilities, product liability, and firm structure where the standard assumptions of uniform behavior miss the salient features of human behavior and social interactions.
We investigate whether the diseases for which there was more biomedical innovation had larger 1999–2019 reductions in premature mortality. Biomedical innovation related to a disease is measured by the change in the mean vintage of descriptors of PubMed articles about the disease. We analyze data on 286 million descriptors of 27 million articles about over 800 diseases. Premature mortality from a disease is significantly inversely related to the lagged vintage of descriptors of articles about the disease. In the absence of biomedical innovation, age-adjusted mortality rates would not have declined. Some factors other than biomedical innovation (e.g., a decline in smoking and an increase in educational attainment) contributed to the decline in mortality. But other factors (e.g., a rise in obesity and the prevalence of chronic conditions) contributed to an increase in mortality. Biomedical innovation reduced the mortality of white people sooner than it reduced the mortality of black people.
The exponential growth of cross-border data flows and fragmented national and regional data protection standards have intensified regulatory challenges in global trade. The effects of regulatory divergence are amplified by a lack of transparency, potentially masking discriminatory practices. Article VII of the General Agreement on Trade in Services (GATS) offers a framework for recognition agreements to bridge these gaps but is not utilized in practice. This paper examines the interplay between GATS Article VII and the EU data adequacy decisions – currently the most comprehensive bilateral framework for assessing compatibility between data protection regimes among other WTO members. It argues that data adequacy frameworks qualify as recognition agreements/arrangements under GATS, offering potential to reduce the trade effects of differences in data protection laws globally while safeguarding regulatory autonomy. A roadmap for leveraging Article VII to advance international alignment is developed to help realize the dual goals of enhancing global cooperation and strengthening privacy protection.
This study examines longer-run usage frequency of Mirt improved biomass cookstoves (ICS), one of the most important ICS promoted in Ethiopia. Mirt has been shown to improve childhood health, and reduce fuelwood consumption and greenhouse gas emissions, but to generate those benefits, households must regularly use it over extended periods. Thus, this paper focuses on longer-run use using stove surface temperature data over five time intervals. We find that, close to its estimated lifespan, 63 per cent of households had their stoves in place after more than 3.5 years. Of those who abandoned their stoves, over 80 per cent did so due to breakage, indicating little abandonment of functional stoves. Among those who retained their stoves, despite the relatively long time frame, we observe no decline in regular usage, suggesting the ICS deliver long-term benefits. We find no correlation of dis-adoption with three randomly assigned monetary treatments and no effect of treatments on long-run usage frequency.
This article extends the validity of the conditional likelihood ratio (CLR) test developed by Moreira (2003, Econometrica 71(4), 1027-–1048) to instrumental variable regression models with unknown homoskedastic error variance and many weak instruments. We argue that the conventional CLR test with estimated error variance loses exact similarity and is asymptotically invalid in this setting. We propose a modified critical value function for the likelihood ratio (LR) statistic with estimated error variance, and prove that our modified test achieves asymptotic validity under many weak instruments asymptotics. Our critical value function is constructed by representing the LR using four statistics, instead of two as in Moreira (2003, Econometrica 71(4), 1027-–1048). A simulation study illustrates the desirable finite sample properties of our test.
In this paper, we study the relative tax advantages of traditional and Roth retirement accounts in the United States by examining the retrospective tax benefits of each account type for the 2003 cohort of retirees. We use the actual history of marginal tax rates at the individual level to estimate that the average tax shields of traditional and Roth retirement accounts‒the excess value of retirement consumption financed by those accounts relative to brokerage accounts‒were 68 percent and 47 percent, respectively. Traditional accounts were better for this cohort largely due to tax cuts in 2001 and 2003. Under a counterfactual with inflation-adjusted 2019 law, the average tax shields for traditional and Roth accounts would have been much closer (33% and 30%, respectively), and nearly half of savers would have achieved higher retirement by saving in Roth accounts rather than in traditional accounts. This is the first paper to apply the history of marginal tax rates‒informed by administrative income records‒to compare Roth and traditional accounts for a particular cohort of retirees.
This paper investigates a well-known downside protection strategy called the constant proportion portfolio insurance (CPPI) in defined contribution (DC) pension fund modeling. Under discrete time trading CPPI, an investor faces the risk of portfolio value hitting the floor which denotes the process of guaranteed portfolio values. In this paper, we question how to deal with so-called ‘gap risk’ which may appear due to uncontrollable events resulting in a sudden drop in the market. In the market model considered, the risky asset price and the labor income are assumed to be continuous-time stochastic processes, whereas trading is restricted to discrete-time. In this setting, an exotic option (namely, the ‘cushion option’) is proposed with the aim of reducing the risk that the portfolio value falls below the defined floor. We analyze the effectiveness of the proposed exotic option for a DC plan CPPI strategy through Monte Carlo simulations and sensitivity analyses with respect to the parameters reflecting different setups.
Catalyzed by the surge in climate litigation worldwide, this article examines the tension between the moral imperatives of intergenerational justice and the operational constraints of positivist legal frameworks. It hypothesizes that while positivist doctrine prima facie challenges judicial application of intergenerational justice principles, reconciliation is possible through contextually attuned adjudication and evolved conceptions of legal principles for the Anthropocene. The article explores three key litigation strategies: dynamic interpretation of existing rights, application of constitutional future generations clauses, and procedural mechanisms for representing future interests. Building on European climate judgments, it analyzes how these approaches strain positivist tenets and animate separation-of-powers objections. The article argues that addressing interpretive and foundational challenges posed by climate change requires both doctrinal innovation and theoretical reconstruction. It shows how contextual constitutionalism can help courts to acknowledge intergenerational duties while preserving legal determinacy, and explores how positivism might evolve to accommodate multigenerational climate governance. Situating leading cases within debates between positivism and non-positivist theories, the article offers a roadmap for developing a framework of legal validity suited to the era-defining challenge of climate change.
In this study, a novel measure of interest in all (264) natural or mixed World Heritage sites sourced from an online platform is contrasted with the degree and number of threats as formally identified by the UNESCO (in its State of Conservation database) and the IUCN (in its Conservation Outlook Assessment reporting), when typical site characteristics are accounted for. Information on TripAdvisor reviews is the digitally sourced measure, and the site characteristics originate from the UNESCO World Heritage database including size, year of inscription, kind of site as well as a distinction between mixed and fully natural sites. Results reveal that the number of reviews and threats both relate to years of inscription, kind of site and to a certain extent continent. The degree of threat reacts to all site characteristics except continent. The analysis reveals that TripAdvisor measures the popularity of the site, although this does not automatically mean that it is also threatened.
In this paper, we consider estimating spot/instantaneous volatility matrices of high-frequency data collected for a large number of assets. We first combine classic nonparametric kernel-based smoothing with a generalized shrinkage technique in the matrix estimation for noise-free data under a uniform sparsity assumption, a natural extension of the approximate sparsity commonly used in the literature. The uniform consistency property is derived for the proposed spot volatility matrix estimator with convergence rates comparable to the optimal minimax one. For high-frequency data contaminated by microstructure noise, we introduce a localized pre-averaging estimation method that reduces the effective magnitude of the noise. We then use the estimation tool developed in the noise-free scenario and derive the uniform convergence rates for the developed spot volatility matrix estimator. We further combine kernel smoothing with the shrinkage technique to estimate the time-varying volatility matrix of the high-dimensional noise vector. In addition, we consider large spot volatility matrix estimation in time-varying factor models with observable risk factors and derive the uniform convergence property. We provide numerical studies including simulation and empirical application to examine the performance of the proposed estimation methods in finite samples.
This paper addresses the persistent ambiguity in the evaluation of legitimate expectations within investor–state dispute settlement (ISDS), critically examining this through Fuller’s interactional theory. Traditional approaches fail to adequately capture the evolving socio-economic contexts and the dynamic nature of investor–state interactions. This paper introduces a novel analytical model that integrates Fuller’s principles, emphasizing continuous dialogue and mutual understanding between investors and host states. By shifting focus from static legal interpretations to interaction-based assessments, this framework provides a more equitable and context-sensitive method for adjudicating legitimate expectations. The research offers significant academic contributions by redefining the foundational principles of legitimate expectations in ISDS, highlighting the necessity of procedural fairness and shared understanding. Practically, it proposes actionable guidelines for tribunals and policymakers to enhance the legitimacy and predictability of investment arbitration. This includes revising bilateral investment treaties (BITs) for explicit policy disclosure and fostering ongoing communication between parties. The adoption of Fuller’s interactional theory in ISDS not only clarifies legal ambiguities but also promotes a more cooperative and transparent investment climate, ultimately benefiting both investors and host states.
The international community has consistently emphasized the importance of protecting the Amazon rainforest as a global carbon reservoir and climate regulator. Basin states have historically responded by rejecting the ‘internationalization of the Amazon’, arguing that they have sovereign rights to exploit the area under their own development plans. By reaffirming their sovereignty rights over international environmental concerns, they have also excluded the ancestral rights of Indigenous peoples in the basin. This article examines how the principles of absolute sovereignty (‘enclosure’), ‘common heritage of humankind’, and ‘common concern of humankind’ have been incorporated into the discourses, instruments, and practices of international environmental governance of the Amazon. These principles interact through shared anthropocentric, ethnocentric, and state-centric premises. Through an analysis of the Amazon Cooperation Treaty Organization (ACTO), the article finds that despite the discursive rejection of international forces, the basin states appeal to ‘common concern’ to embrace international cooperation while promoting transnational extractive and infrastructure projects through the principle of ‘enclosure’. This produces fragmented governance that legitimizes the expansion of extractivism under sovereign and developmental imaginaries while excluding the self-determination claims and ecological perspectives of the Indigenous peoples of the Amazon.