Arild Underdal has been at the center of an important community of scholars studying global environmental governance. Since the 1990s that community, along with many other scholars globally, has offered important insights into the design and management of international institutions that can lead to more effective management of environmental problems. At the same time, diplomats have made multiple attempts to create institutions to manage the dangers of climate change. This essay looks at what has been learned by both communities—scholars and practitioners—as their efforts co-evolved. It appears that despite a wealth of possible insights into making cooperation effective very few of the lessons offered by scholars had much impact during the first two decades of climate change diplomacy. Indeed, basic concepts from cooperation theory and evidence from case studies—many developed in Arild’s orbit—can explain why those two decades achieved very little real cooperation. The new Paris agreement may be changing all that and much better reflects insights from scholars about how to build effective international institutions. Success in the Paris process is far from assured and scholars can contribute a lot more with a more strategic view of when and how they have an impact.

The San Diego Regional Decarbonization Framework’s Technical Report provides technical and policy pathways to decarbonization in the medium-term to inform near-term policymaking in regional, County, and city governments. The report models science-based pathways to net zero carbon emissions for the San Diego region by 2045, consistent with the Paris Climate Agreement and California State mandates. The pathways provide a shared vision for the San Diego region to collectively reduce net GHG emissions in alignment with California’s net zero goal. This report is a technical analysis of how different sectors in the energy system can contribute to decarbonization, but does not identify the “right” pathway. Instead, it shows numerous ways to achieve regional emissions goals in multiple sectors to highlight trade-offs, co-benefits, decision points, risks, and synergies. The analyses and pathways should be updated as technologies evolve or uncertainties are resolved or clarified. To that end, the report explores policy processes to help regional jurisdictions learn about uncertainties and adjust strategies as information arises.

Though highly motivated to slow the climate crisis, governments may struggle to impose costly polices on entrenched interest groups, resulting in a greater need for negative emissions. Here, we model wartime-like crash deployment of direct air capture (DAC) as a policy response to the climate crisis, calculating funding, net CO₂ removal, and climate impacts. An emergency DAC program, with investment of 1.2-1.9% of global GDP annually, removes 2.2-2.3 GtCO₂ yr^-1 in 2050, 13-20 GtCO₂ yr^-1 in 2075, and 570-840 GtCO₂ cumulatively over 2025-2100. Compared to a future in which policy efforts to control emissions follow current trends (SSP2-4.5), DAC substantially hastens the onset of net-zero CO₂ emissions (to 2085-2095) and peak warming (to 2090-2095); yet warming still reaches 2.4-2.5 °C in 2100. Such massive CO₂ removals hinge on near-term investment to boost the future capacity for upscaling. DAC is most cost-effective when using electricity sources already available today: hydropower and natural gas with renewables; fully renewable systems are more expensive because their low load factors do not allow efficient amortization of capital-intensive DAC plants.

There is heated debate over the wisdom and effect of secrecy in international negotiations. This debate has become central to the process of foreign investment arbitration because parties to disputes nearly always can choose to hide arbitral outcomes from public view. Working with a new database of disputes at the world's largest investor-state arbitral institution, the World Bank's International Centre for Settlement of Investment Disputes, the authors examine the incentives of firms and governments to keep the details of their disputes secret. The authors argue that secrecy in the context of investment arbitration works like a flexibility-enhancing device, similar to the way escape clauses function in the context of international trade. To attract and preserve investment, governments make contractual and treaty-based promises to submit to binding arbitration in the event of a dispute. They may prefer secrecy in cases when they are under strong political pressure to adopt policies that violate international legal norms designed to protect investor interests. Investors favor secrecy when managing politically sensitive disputes over assets they will continue to own and manage in host countries long after the particular dispute has passed. Although governments prefer secrecy to help facilitate politically difficult bargaining, secrecy diminishes one of the central purposes of arbitration: to allow governments to signal publicly their general commitment to investor-friendly policies. Understanding the incentives for keeping the details of dispute resolution secret may help future scholars explain more accurately the observed patterns of wins and losses from investor-state arbitration as well as patterns of investment.

This paper develops a new microgrid investment planning model that determines cost-optimal investment and operation of distributed energy resources (DERs) in a microgrid. We formulate the problem in a bilevel framework, using particle swarm optimization to determine investment and the DER-CAM model (Distributed Energy Resources Customer Adoption Model) to determine operation. The model further uses sequential Monte Carlo simulation to explicitly simulate power outages and integrates time-varying customer damage functions to calculate interruption costs from outages. The model treats nonlinearities in reliability evaluation directly, where existing linear models make critical simplifying assumptions. It combines investment, operating, and interruption costs together in a single objective function, thereby treating reliability endogenously and finding the cost-optimal trade-off between cost and reliability—two competing objectives. In benchmarking against a version of the DER-CAM model that treats reliability through a constraint on minimum investment, our new model improves estimates of reliability (the loss of load expectation) by up to 600%, of the total system cost by 6%–18%, of the investment cost by 32%–50%, and of the economic benefit of investing 27%–47%. Improvements stem from large differences in investment of up to 56% for natural gas generators, solar photovoltaics, and battery energy storage.

Why do some decision makers prefer big multilateral agreements while others prefer cooperation in small clubs? Does enforcement encourage or deter institutional cooperation? We use experiments drawn from behavioral economics and cognitive psychology - along with a substantive survey focused on international trade - to illustrate how two behavioral traits (patience and strategic reasoning) of individuals who play key roles in negotiating and ratifying an international treaty shape their preferences for how treaties are designed and whether they are ratified. Patient subjects were more likely to prefer treaties with larger numbers of countries (and larger long-term benefits), as were subjects with the skill to anticipate how others will respond over multiple iterations of strategic games. The presence of an enforcement mechanism increased subjects' willingness to ratify treaties; however, strategic reasoning had double the effect of adding enforcement to a trade agreement: more strategic subjects were particularly likely to favor ratifying the agreement. We report these results for a sample of 509 university students and also show how similar patterns are revealed in a unique sample of ninety-two actual US policy elites. Under some conditions certain types of university student convenience samples can be useful for revealing elite-dominated policy preferences - different types of people in the same situation may prefer to approach decision-making tasks and reason through trade-offs in materially different ways.