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Eight key takeaways from the new National Climate Assessment » Yale Climate Connections

The U.S. has made progress in reducing heat-trapping carbon pollution, but extreme weather caused by climate change is harming U.S. residents in every region, according to the National Climate Assessment released in November 2023.

Here are eight things to know about the report.

1. The National Climate Assessments are authoritative scientific reports

The Global Change Research Act, passed in 1990, mandates that the U.S. Global Change Research Program should deliver a comprehensive climate report to “understand, assess, predict, and respond to human-induced and natural processes of global change” every four years or so. Iterations of the report were published in 2000, 2009, 2014, 20172018, and just recently, in 2023.

The National Climate Assessment is essentially a U.S.-focused version of the seminal Intergovernmental Panel on Climate Change report, bringing together top climate scientists to summarize the latest and best research about climate change science, impacts, and solutions. These reports represent the expert consensus on these topics.

The latest Fifth National Climate Assessment includes 37 chapters plus appendices written by hundreds of contributing scientific authors, including an overview, a list of key take-home messages, and 388 charts and figures, for those who lack the time to wade through the entire voluminous report.

2. The U.S. is disproportionately responsible for climate change

The report begins with a discussion of climate trends, noting that human-caused global warming has heated the planet by about 1.1 degrees Celsius (2 degrees Fahrenheit) since the late 1800s. Cumulative U.S. climate pollution over that period is responsible for about 17% of the global warming to date, even though the United States only accounts for about 4% of the world population.

3. U.S. climate pollution is falling, but not fast enough

But the country is making progress in curbing those emissions, which the report notes peaked in 2007 and fell 16% by 2022 — a decline of about 1% per year.

That’s largely a result of cleaner electricity sources replacing coal, which caused power sector emissions to fall by 40%. The report notes that “wind and solar energy costs dropped 70% and 90%, respectively, over the last decade,” and have accounted for over 80% of new electricity generation capacity installed in the United States in each of the past several years.

But this progress needs to accelerate even faster yet, the report says: “U.S. net greenhouse gas emissions remain substantial and would have to decline by more than 6% per year on average [by 2030], reaching net-zero emissions around midcentury, to meet current national mitigation targets and international temperature goals.”

charts showing falling costs of solar and wind and rising electricity-generating capacity for both
Figure 1.2 in the Fifth National Climate Assessment: “Costs of onshore wind (a), solar photovoltaics (b), and electric vehicle (EV) batteries (c) have decreased sharply as the cumulative capacities of wind and solar generation (d and e) and the cumulative number of EVs sold (f) have increased. Figure credit: Electric Power Research Institute, National Renewable Energy Laboratory, NOAA NCEI, and CISESS NC.”

4. Extreme weather is getting more frequent and severe

The report notes that extreme weather events such as heat waves, heavy precipitation, drought, flooding, wildfires, and hurricanes are becoming more frequent and/or severe across the United States, and are causing increasing damages.

“In the 1980s, the country experienced, on average, one (inflation-adjusted) billion-dollar disaster every four months. Now, there is one every three weeks, on average,” the report’s authors wrote. “Extreme events cost the U.S. close to $150 billion each year — a conservative estimate that does not account for loss of life, healthcare-related costs, or damages to ecosystem services.”

5. Climate change is worsening inequality

Low-income communities, communities of color, tribes and Indigenous peoples are disproportionately exposed to weather disasters and lack the resources to adapt to and recover from them. As a result, climate change is worsening long-standing inequities within the country.

6. Climate change is bad for the economy

Another key finding from the economics chapter is that climate change is slowing U.S. economic growth. Because slow growth results in compounding effects over time, this could cost the American economy tens of trillions of dollars over the coming decades if efforts to curb climate change are unsuccessful.

7. Green jobs are booming

The new report details many opportunities to mitigate and minimize the risks of climate change. For example, “employment gains in electrification and renewable energy industries are projected to far outpace job losses in fossil fuel industries,” it said.

8. We still have options

To adapt to some of the already locked-in climate changes, people can redesign cities and buildings to address heat. We can shift water-intensive industries to match projected rainfall patterns and direct new housing development to less flood-prone areas. The report finds that mitigation and adaptation actions can result in immediate, economic, jobs, health, ecosystem, and social justice benefits.

Solving the climate crisis won’t be easy, but we’re already making progress moving in the right direction, and the faster we deploy those solutions, the better the future will be.

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