The future evolution of global natural gas trade.

Understanding the long-term evolution of natural gas is critical in the context of long-term energy system transitions. Here, we explicitly represent traded pipeline and liquefied natural gas (LNG) infrastructure in the Global Change Analysis Model (GCAM). We find LNG to make up a dominant share of gas trade, as it can be flexibly shipped across regions. New global investments in LNG and pipeline export infrastructure respectively range from 230 to 840 and 70-620 million tons per annum (MTPA) by 2050 across scenarios; the lower end of this range is achieved through transitioning to low-carbon energy systems along with limited trade. Our results also highlight diverging implications for regions based on their gas trade profiles. For example, Russia, which produces gas largely for pipeline exports may experience greater production losses due to liquefaction and shipping improvements and geopolitical shifts than regions oriented more toward domestic and LNG markets, such as USA and Middle East.

Net-Zero CO2 by 2050 Scenarios for the United States in the Energy Modeling Forum 37 Study.

The Energy Modeling Forum (EMF) 37 study on deep decarbonization and high electrification analyzed a set of scenarios that achieve economy-wide net-zero carbon dioxide (CO2) emissions in North America by mid-century, exploring the implications of different technology evolutions, policies, and behavioral assumptions affecting energy supply and demand. For this paper, 16 modeling teams reported resulting emissions projections, energy system evolution, and economic activity. This paper provides an overview of the study, documents the scenario design, provides a roadmap for complementary forthcoming papers from this study, and offers an initial summary and comparison of results for net-zero CO2 by 2050 scenarios in the United States. We compare various outcomes across models and scenarios, such as emissions, energy use, fuel mix evolution, and technology adoption. Despite disparate model structure and sources for input assumptions, there is broad agreement in energy system trends across models towards deep decarbonization of the electricity sector coupled with increased end-use electrification of buildings, transportation, and to a lesser extent industry. All models deploy negative emissions technologies (e.g., direct air capture and bioenergy with carbon capture and storage) in addition to land sinks to achieve net-zero CO2 emissions. Important differences emerged in the results, showing divergent pathways among end-use sectors with deep electrification and grid decarbonization as necessary but not sufficient conditions to achieve net zero. These differences will be explored in the papers complementing this study to inform efforts to reach net-zero emissions and future research needs.

The Energy System Transformation Needed to Achieve the U.S. Long-Term Strategy.

The authors designed and executed the integrated assessment modeling for the United States Long-Term Strategy. They bring diverse expertise to the modeling and analysis of United States decarbonization. Russell Horowitz, Matthew Binsted, and Haewon McJeon are scientists at the Joint Global Change Research Institute, a partnership between Pacific Northwest National Laboratory and the University of Maryland. Allen Fawcett, James McFarland, and Morgan Browning are economists at the Environmental Protection Agency's Climate Economics Branch. Claire Henly is White House Fellow at the Office of the U.S. Special Presidential Envoy for Climate. Nathan Hultman is the Director of the Center for Global Sustainability at the University of Maryland.

Can updated climate pledges limit warming well below 2°C?

Increased ambition and implementation are essential.

Agricultural impacts of sustainable water use in the United States.

Governance measures such as restrictions on groundwater pumping and adjustments to sectoral water pricing have been suggested as response strategies to curtail recent increases in groundwater pumping and enhance sustainable water use. However, little is known about the impacts of such sustainability strategies. We investigate the implications of such measures, with the United States (U.S.) as an example. Using the Global Change Analysis Model (GCAM) with state-level details in the U.S., we find that the combination of these two governance measures can drastically alter agricultural production in the U.S. The Southwest stands to lose upwards of 25% of their total agricultural production, much of which is compensated for by production increases in river basins on the east coast of the U.S. The implementation of future sustainable water governance measures will require additional investments that allow farmers to maximize production while minimizing water withdrawals to avoid potentially detrimental revenue losses.

Power sector investment implications of climate impacts on renewable resources in Latin America and the Caribbean.

Climate change mitigation will require substantial investments in renewables. In addition, climate change will affect future renewable supply and hence, power sector investment requirements. We study the implications of climate impacts on renewables for power sector investments under deep decarbonization using a global integrated assessment model. We focus on Latin American and Caribbean, an under-studied region but of great interest due to its strong role in international climate mitigation and vulnerability to climate change. We find that accounting for climate impacts on renewables results in significant additional investments ($12-114 billion by 2100 across Latin American countries) for a region with weak financial infrastructure. We also demonstrate that accounting for climate impacts only on hydropower-a primary focus of previous studies-significantly underestimates cumulative investments, particularly in scenarios with high intermittent renewable deployment. Our study underscores the importance of comprehensive analyses of climate impacts on renewables for improved energy planning.