Regional Analysis

The latest United Nations IPCC Reports describe how limiting global warming to 1.5 degrees Celsius above pre-industrial levels can avert the worst impacts of climate change. That will require global emissions to drop by roughly half over the next decade and reach net-zero emissions near midcentury.

Six leading models agree: Rapid decarbonization of power, transportation sectors key to a successful energy transition
Actions for reducing US emissions at least 50% by 2030

Abstract: Pathways for limiting global warming to 1.5° and 2°C generally involve net-zero greenhouse gas (GHG) emissions economy-wide near mid-century and halving emissions over the next decade. Updated pledges by countries and companies around the 2021 United Nations climate conference reflect this sense of urgency. The updated US pledge to reduce net emissions 50 to 52% by 2030 would represent a tripling of the pace of historical reductions.

We report on a six-model intercomparison of potential actions to reach the US target of at least 50% GHG reductions by 2030. This analysis helps identify which findings are more robust or uncertain given different model structures and input assumptions. Models highlight the central roles of clean electricity and electrification, the large scale of deployment needed relative to historical levels and scenarios with only current policies, and a range of benefits from near-term action.

The most recent United Nations climate change report indicates that without significant action to mitigate global warming, the extent and magnitude of climate impacts—from floods to droughts to the spread of disease—could outpace the world’s ability to adapt to them. The latest effort to introduce meaningful climate legislation in the United States Congress, the Build Back Better bill, has stalled.

Absent legislative victory, the President can still meet U.S. climate goals

First held in 1970, Earth Day is an annual observance on April 22 that promotes the need for environmental protection. Earth Day now comprises multiple events around the world under the coordination of EarthDay.org. The official theme for this year's Earth Day is Invest In Our Planet, To that end, the Earth Day 2022 website states:

Four new videos highlight the impact of the MIT Joint Program on the Science and Policy of Global Change
Meeting U.S. greenhouse gas emissions goals with the International Air Pollution Provision of the Clean Air Act

Abstract: We explore economic, distributional and health consequences of U.S. greenhouse gas emissions objectives that could be achieved using Section 115 of the Clean Air Act (international air pollution) which has only recently received detailed legal analysis as a potential U.S. climate policy tool. Under it a national emissions target could be allocated among the states. This illustrative analysis considers 45% and 50% reductions of energy and industry-related CO2 emissions by 2030, below 2005 levels, via a model rule. Different approaches (based on legal precedent) for the interstate allocation are considered, along with alternative rates of technology improvement.

The detail needed to analyze this approach is provided by MIT’s U.S. Regional Energy Policy (USREP) model (30 individual states and regions), with its electricity sector replaced by the U.S. National Renewable Energy Laboratory’s Renewable Energy Development System (ReEDS). Air quality benefits are estimated using modeling tools developed by academic researchers and the U.S. Environmental Protection Administration.

Three-quarters of emissions reductions in 2030 come in the electric sector, while reductions elsewhere illustrate the efficiency advantage of a multi-sector policy. With all states participating in allowance trading, the resulting national emissions price is lower than in older assessments. The difference is due to lower growth expectations, recent state policies, falling costs of low carbon technologies, and an improved representation of electric system flexibility by the ReEDS model. Even ignoring climate and air quality benefits, economic welfare grows at near the baseline rate for all regions regardless of the interstate allocation approach. When states distribute allowance revenue to residents on an equal per-capita basis the policy is welfare improving to the lowest income quintile in all regions. Aggregation of control costs, the mortality effects of reduced particulates, and the value of avoided climate damages yields positive national net benefits in all cases.

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