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Climate Change Puts U.S. At Risk, New Federal Report Warns

Updated: Jan 9, 2019

The Fourth National Climate Assessment (NCA4) was released Friday and its findings are a stark contrast to the Trump Administration's climate claims.

Cover for the report. IMG credit: U.S. Global Change Research Program

The Fourth National Climate Assessment (NCA4) was released less than 30 days after the IPCC special report. At the bottom of this page you will find links to all of the 29 chapter's executive summaries (except the first one), which are only 3 pages each. The report was written by a science panel representing 13 federal agencies.

NCA4: Effects of Climate Change

NCA4 says that climate change is an increasing threat to life, property, and ecosystems across the world. It states that the economic damage from natural disasters, droughts, heat waves, and sea level rise will increase throughout the next decade.

The report says that we can reduce these effects if we cap global warming at 2ºC over pre-industrial levels. U.S. temperatures have already risen 1.8ºC since the beginning of the Industrial era. Similar to the IPCC report, it emphasizes the importance of governments acting on climate change. It also underscored that the Trump Administration is moving in the opposite direction, without directly stating it.

The report emphasizes some key points, including that global warming is:

  • Intensifying and increasing deluges (extreme rainfall) that cause damaging floods and crop loss.

  • Putting areas at temperature risk: heat waves in the Midwest alone could kill up to 2,000 more people yearly by 2090, and Chicago's climate could be more like Phoenix's climate–reaching 100ºF for months during the summer.

  • Increasing the drying of land and vegetation, which leads to crop loss and deadly wildfires.

  • Harming U.S. Forests via making them more vulnerable to fire and insects, reducing their ability to store carbon, and disrupting their wildlife.

  • Creating multiple threats for coastal communities, including significant shifts in fish populations, ocean acidification, direct flooding damage from rising sea level and tropical storms. Along the coasts, $1 trillion in public infrastructure and private property are threatened by flooding, rising sea level and storm surges.

  • Threatening indigenous people's lives via affecting fishing, agriculture, and forestry

The report looks at what has already happened and what is ahead in each region of the nation.

The report also shows how climate change can affect energy production, multiplying the effects of climate change. For instance, heat waves can affect energy production because there is not enough water to cool down power plants, which can limit manufacturing or health in a hospital.

"Without significant reductions in greenhouse gas emissions, extinctions and transformative impacts on some ecosystems cannot be avoided, with varying impacts on the economic, recreational, and subsistence activities they support"

said National Oceanic and Atmospheric Administration scientist David Easterling, a lead author for the climate science section.

Economic Impacts

Because they now have detailed regional projections, scientists can also project the multi-billion dollar cost of climate change.

"We're finally seeing a lot more economic data. In the past, we could talk about, well this is going to happen, there will be lower streamflow(s), there will be more invasive species, this might happen, that might happen"

said Philip Mote, a climate researcher at the University of Washington who worked on the report.

This chart shows that if greenhouse gas emissions continue at a high rate of RCP 8.5, damage from climate change in the U.S. alone is expected to cost hundreds of billions of dollars a year by 2090. However, if the emissions start to go down and we get to RCP 4.5, then there would still be a high cost, but it would be less. Chart src: Fourth National Climate Assessment

The report says that more economic studies show the rising costs. In the worst-case, high-emissions scenario, global warming costs could total 10 percent of U.S. GDP by the end of the century. Chart src: Fourth National Climate Assessment

Another impact is the risk of the northeast loosing distinct seasons, which is a driving factor in rural and suburban economies.

Farms and Food Systems

Farms and food systems are at a serious risk because of climate change. Under a high-emissions scenario, the Midwest will see greater increases in warm-season temperatures than anywhere else in the country, with the frost-free season projected to increase by an average of 10 days each year from 2016 to 2045, according to the report. Changes in climate will upset the plant cycle.

A rise in temperatures in the Midwest is "projected to be the largest contributing factor to declines in the productivity of U.S. agriculture," the report states, sending agriculture back to 1980 levels, destroying gains made by improving technology.

Millions of People Now at Risk

The report chapters 18 to 27 divided the country into sections and talked about their impacts. The northeast's seasonly patterns could be erased under a high-emissions scenario. The report also underlines the northeast's risk of sea level rise, extreme weather, and degrading air and water quality.

For the southeast, the report shows the threat to urban infrastructure as well as the high threat to health because of higher temperatures, flooding, and new disease. The extreme heat will also have an impact on agriculture, manufacturing, and timber, which are all key parts of the southeast's economy.

Climate change is threatening the Caribbean's freshwater supply by reducing normal rainfall events needed for freshwater and increasing extreme rainfall events (deluges), which will flood the area. Sea level rise will also flood the Caribbean's low-lying land, as well as further contaminate freshwater aquifers with salt water. The Caribbean is also at risk to natural disasters such as Hurricanes Harvey and Irma that destroyed the Caribbean last year. Increases in temperature will lead to agriculture loss and changes in habitat.

These are just 3 of the 10 regions that the report focuses on.

Did Trump Try to Bury It?

The scheduled release for this report was originally in early December, but the Trump Administration moved it to Black Friday. This could have been an attempt to hide it among all the Black Friday news.

Senator Sheldon Whitehouse (D) from Rhode Island said in a statement,

"This report shows how climate change will affect every single one of our communities. The president says outrageous things like climate change is a hoax engineered by the Chinese and raking forests will prevent catastrophic wildfires, but serious consequences like collapsing coastal housing prices and trillions of dollars in stranded fossil fuel assets await us if we don't act"

Fourth National Climate Assessment Executive Summaries

The report included three to four page executive summaries for chapters two to 29. In it there are one to two pages of Key Messages, where the authors outline the key messages that were displayed in the chapter. Click on the link to get the executive summary of that chapter.


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