National Climate Assessment: 5 Takeaways from the U.S. Climate Report

CNN
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The effects of a rapidly warming climate are being felt across the four corners of the United States and will worsen over the next 10 years with continued use of fossil fuels, according to a grim new report from federal agencies.

THE Fifth National Climate Assessmenta congressionally mandated report released approximately every five years, warns that although pollution caused by global warming in the United States is slowly decreasing, it is not happening fast enough to meet the country’s goals, and it is also not in line with the UN-sanctioned goal of limiting global warming to 1.5 degrees Celsius – a threshold beyond which scientists warn that life on Earth will struggle to survive.

This year’s assessment reflects the reality that Americans can increasingly see and feel climate impacts in their own communities, said Katharine Hayhoe, a distinguished climate scientist at Texas Tech University and a contributor to the report.

“Climate change affects every aspect of our lives,” Hayhoe told CNN.

Some of the report’s sweeping conclusions remain sadly familiar: No region of the United States is truly safe from climate disaster; it is essential to significantly reduce the use of fossil fuels to limit the consequences, but we are not doing it fast enough; and every fraction of a degree of warming leads to more intense impacts.

But there are some important new developments: scientists can now say with more confidence when the climate crisis made stronger or more frequent rainstorms, hurricanes and wildfires, long-term drought more severe and the heat more deadly.

This summer alone, the Phoenix area has seen a record 31 consecutive days above 110 degrees, a shocking heat wave that was partly responsible for more than 500 heat-related deaths in Maricopa County in 2023 – its deadliest year for the recorded heat.

In July, torrential rains flooded parts of Vermont in deadly floodwaters. Then, in August, Maui was devastated by a rapid forest fire and the Gulf Coast of Florida was hit by its second major hurricane in two years.

President Joe Biden will deliver a speech Tuesday and is expected to unveil more than $6 billion in funding to build climate resilience “by strengthening the U.S. power grid, investing in water infrastructure upgrades, reducing the risks of flooding for communities and advancing environmental justice for all.” an administration official said.

The United States needs “a transformation of the global economy of a size and scale unprecedented in human history” to “create a livable future for ourselves and our children” , White House senior climate adviser John Podesta told reporters.

Here are five takeaways from the federal government’s sweeping climate report.

The latest report contains an important step forward in what is called “attribution science” – scientists can show more definitively how climate change affects extreme eventssuch as heat waves, droughts, hurricanes and heavy rains.

Climate change doesn’t cause hurricanes or wildfires, but it can make them more intense or more frequent.

For example, warming oceans and air temperatures mean hurricanes become stronger more quickly and dump more precipitation when they hit the shore. And hotter, drier conditions due to climate change can help vegetation and trees become tinderboxes, turning wildfires into out-of-control megafires.

“Now, thanks to the attribution field, we can make specific statements,” Hayhoe said, saying attribution can help identify certain areas of a city that are now more likely to be flooded due to the effects of climate change. “The field of attribution has progressed significantly over the last five years, which really helps people connect the dots. »

No place is safe from climate change, Biden administration officials and the report’s scientists stressed, and this summer’s extreme weather was a deadly reminder.

Some states – including California, Florida, Louisiana and Texas – are experiencing larger storms and extreme variations in precipitation.

Landlocked states will not have to adapt to sea level rise, although some, notably Appalachian states like Kentucky And West Virginia – experienced devastating floods due to torrential rains.

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And northern states are grappling with an increase in tick-borne illnesses, less snow and heavier rainstorms.

“There’s no place where it’s not at risk, but there are places that are more or less at risk,” Hayhoe told CNN. “It depends both on the increasingly frequent and severe weather and climate extremes you are exposed to, as well as how prepared (cities and states) are.”

Climate shocks to the economy are occurring more frequently, the report says, as evidenced by new record this year for the number of extreme weather disasters costing at least $1 billion. And disaster experts have spent the last year warning that the United States is only beginning to see the economic consequences of the climate crisis.

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Climate risks are hit the housing market in the form of skyrocketing home insurance rates. Some insurers have pulled out of high-risk states altogether.

More severe storms wiping out some crops or extreme heat killing livestock can cause food prices to skyrocket. And in the Southwest, the report’s researchers found that higher temperatures in the future could lead to a 25% loss in physical work capacity among agricultural workers from July to September.

Unlike that of the world other major polluters – China and India – in the United States, pollution linked to global warming is decreasing. But it’s not happening fast enough to stabilize global warming or meet U.S. international climate commitments, the report says.

The country’s annual greenhouse gas emissions fell by 12% between 2005 and 2019, largely due to the power sector’s shift away from coal to renewable energy and methane, the latter of which is still a fossil fuel that has a significant effect on global warming. .

This decline is good news for the climate crisis, but if we look at the fine print, the picture is mixed.

The report estimates that US emissions linked to global warming “remain substantial” and would need to decline sharply by 6% per year on average to comply with the international target of 1.5 degrees. To put this reduction in perspective, US emissions fell by less than 1% per year between 2005 and 2019 – a tiny annual decline.

Water – too much and not enough – is a huge problem for the United States

One of the most important points of the report focuses on the precarious future of water in the United States and how parts of the country face a future characterized by either extreme drought and water insecurity or by more flooding and sea level rise.

Drought and diminishing snowpack pose enormous threats to communities in the Southwest in particular. The Southwest chapter of the report, authored by Arizona State University climatologist Dave White, found that the region was significantly drier from 1991 to 2020 than the previous three decades.

White said it was a worrying sign as the planet continues to warm, with significant threats to the snowpack in California’s Sierra Nevada Mountains and the Rocky Mountains, both of which provide crucial fresh water for the West.

White added that the lack of fresh water in the region also has significant economic and agricultural impacts, as it supports towns, farms and Native American tribes.

“The mountains are our natural reservoirs in the region,” White told CNN. “Climatic impacts on mountain snow cover have very significant negative effects on the functioning of our infrastructure. It is simply essential for us to protect these resources.

CNN’s Donald Judd contributed to this report.