In October 2021, Stanford University’s Precourt Institute for Energy, Stanford Center at Peking University, and Shorenstein Asia-Pacific Research Center’s China Program partnered with Peking University’s Institute of Energy to organize a series of roundtables intended to promote discussion around how China and the United States can accelerate decarbonization and cooperate with one another to meet their carbon neutrality goals by mid-century. The thematic areas included U.S.- China collaboration on climate change, global sustainable finance, corporate climate pledges, and the opportunities and challenges for the acceleration of decarbonization in both countries in general, as well as specifically for the power, transportation, and industry sectors.

The roundtable series brought together leading American and Chinese current and former officials, and experts in the public and private sectors working on energy, climate, the environment, industry, transportation, and finance. This report reviews the key themes and takeaways that emerged from the closed-door discussions. It builds on the “U.S.-China Joint Statement Addressing the Climate Crisis” released by the U.S. Department of State on April 17, 2021 and shares some common themes with the “U.S.-China Joint Glasgow Declaration on Enhancing Climate Action in the 2020s” released on November 10, 2021.

This report further identifies more concrete and additional promising areas for accelerated decarbonization and bilateral collaboration, as well as the obstacles to be tackled, including institutional, political, and financial constraints. This report could serve as a basis for concrete goals and measures for future U.S.-China cooperation on energy and the climate. It also highlights the contributions universities can make to the global energy transition. The roundtable series identifies areas most critical or potent for bilateral collaboration, paving the way for concrete action plans at the national, local, and sectoral levels. Section 1 offers a brief overview of the acceleration of decarbonization in the U.S. and in China. Section 2 identifies the opportunities and challenges of U.S.-China cooperation on climate change. Sections 3-7 delve into specific promising areas for accelerated decarbonization and opportunities and hurdles for bilateral collaboration in corporate, finance, power, transportation, and industrial sectors.

This report is not a comprehensive review of all the relevant areas pertaining to decarbonization in China and the U.S. and bilateral collaboration on climate change. For example, this roundtable series focused on climate mitigation. Another strategy to respond to climate change is adaption, which we reserve for potential future discussion in a separate report. Additionally, the focus of this report is on energy. Important measures such as reforestation as a carbon sink are reserved for separate discussions. The views expressed in this report represent those of the participants at the roundtable series and do not necessarily represent the positions of the organizing institutions. Chatham House rules were used throughout the roundtables to facilitate open and frank discussion, so views are not attributed to individual participants

Sugar is the second largest agro-based industry in India and has a major influence on the country's water, food, and energy security. In this paper, we use a nexus approach to assess India's interconnected water-food-energy challenges, with a specific focus on the political economy of the sugar industry in Maharashtra, one of the country's largest sugar producing states. Our work underscores three points. First, the governmental support of the sugar industry is likely to persist because policymakers are intricately tied to that industry. Entrenched political interests have continued policies that incentivize sugar production. As surplus sugar has been produced, the government introduced additional policies to reduce this excess and thereby protect the sugar industry. Second, although the sugar economy is important to India, sugar policies have had detrimental effects on both water and nutrition. Long-standing government support for sugarcane pricing and sales has expanded water-intensive sugarcane irrigation in low-rainfall areas in Maharashtra, which has reduced the state's freshwater resources and restricted irrigation of more nutritious crops. Despite its poor nutritional value, empty-calorie sugar has been subsidized through the public distribution system. Third, the Indian government is now promoting sugarcane-based ethanol production. This policy has the benefit of providing greater energy security and creating a new demand for surplus sugar in the Indian market. Our analysis shows that a national biofuel policy promoting the production of ethanol from sugarcane juice versus directly from molasses may help reduce subsidized sugar for human consumption without necessarily expanding water and land use for additional production of sugarcane.

This paper formulates and estimates a household-level, billing-cycle water demand model under increasing block prices that accounts for the impact of monthly weather variation, the amount of vegetation on the household’s property, and customer-level heterogeneity in demand due to household demographics. The model utilizes US Census data on the distribution of household demographics in the utility’s service territory to recover the impact of these factors on water demand. An index of the amount of vegetation on the household’s property is obtained from NASA satellite data. The household-level demand models are used to compute the distribution of utility-level water demand and revenues for any possible price schedule. Knowledge of the structure of customer-level demand can be used by the utility to design nonlinear pricing plans that achieve competing revenue or water conservation goals, which is crucial for water utilities to manage increasingly uncertain water availability yet still remain financially viable. Knowledge of how these demands differ across customers based on observable household characteristics can allow the utility to reduce the utility-wide revenue or sales risk it faces for any pricing plan. Knowledge of how the structure of demand varies across customers can be used to design personalized (based on observable household demographic characteristics) increasing block price schedules to further reduce the risk the utility faces on a system-wide basis. For the utilities considered, knowledge of the customer-level demographics that predict demand differences across households reduces the uncertainty in the utility’s system-wide revenues from 70 to 96 percent. Further reductions in the uncertainty in the utility’s system-wide revenues in the, range of 5 to 15 percent, are possible by re-designing the utility’s nonlinear price schedules to minimize the revenue risk it faces given the distribution of household-level demand in its service territory.

Researchers including David Lobell analyze how human-caused climate change has impacted a water deficit in Southern Africa and might contribute to a rising food security crisis in the region.

Many mountainous and high‐latitude regions have experienced more precipitation as rain rather than snow due to warmer winter temperatures. Further decreases in the annual snow fraction are projected under continued global warming, with potential impacts on flood risk. Here, we quantify the size of streamflow peaks in response to both seasonal and event‐specific rain‐fraction using stream gage observations from watersheds across the western United States. Across the study watersheds, the largest rainfall‐driven streamflow peaks are >2.5 times the size of the largest snowmelt‐driven peaks. Using a panel regression analysis of individual precipitation and snowmelt events, we show that the empirical streamflow response grows approximately exponentially as the liquid precipitation input increases, with rain‐dominated runoff leading to proportionately larger streamflow increases than snowmelt or mixed rain‐and‐snow runoff. We find that the response to changes in rain percentage is largest in the wettest watersheds, where wet antecedent conditions are important for increasing runoff efficiency. Similarly, the effect of rain percentage is larger across watersheds in the Northwest and West regions compared to watersheds in the Northern Rockies and Southwest regions. Overall, as a higher percentage of precipitation falls as rain, increases in the size of rainfall‐driven and “rain‐on‐snow”‐driven floods have the potential to more than offset decreases in the size of snowmelt‐driven floods.

Irrigation has been pivotal in wheat’s rise as a major crop in India and is likely to be increasingly important as an adaptation response to climate change. Here we use historical data across 40 years to quantify the contribution of irrigation to wheat yield increases and the extent to which irrigation reduces sensitivity to heat. We estimate that national yields in the 2000s are 13% higher than they would have been without irrigation trends since 1970. Moreover, irrigated wheat exhibits roughly one-quarter of the heat sensitivity estimated for fully rainfed conditions. However, yield gains from irrigation expansion have slowed in recent years and negative impacts of warming have continued to accrue despite lower heat sensitivity from the widespread expansion of irrigation. We conclude that as constraints on expanding irrigation become more binding, furthering yield gains in the face of additional warming is likely to present an increasingly difficult challenge.

The ratio of plant carbon gain to water use, known as water use efficiency (WUE), has long been recognized as a key constraint on crop production and an important target for crop improvement. WUE is a physiologically and genetically complex trait that can be defined at a range of scales. Many component traits directly influence WUE, including photosynthesis, stomatal and mesophyll conductances, and canopy structure. Interactions of carbon and water relations with diverse aspects of the environment and crop development also modulate WUE. As a consequence, enhancing WUE by breeding or biotechnology has proven challenging but not impossible. This review aims to synthesize new knowledge of WUE arising from advances in phenotyping, modeling, physiology, genetics, and molecular biology in the context of classical theoretical principles. In addition, we discuss how rising atmospheric CO2 concentration has created and will continue to create opportunities for enhancing WUE by modifying the trade-off between photosynthesis and transpiration.