The average global temperature is much higher and rising more rapidly than "anything modern civilization has experienced," according to David Easterling, one of the authors of a new US government report that delivers a dire warning about our future.
Thousands more could die, food will be scarcer, and the US economy could lose hundreds of billions of dollars -- or, in the worst-case scenario, more than 10% of its GDP -- by the end of the century.
Released Friday, the Fourth National Climate Assessment was put together with the help of 1,000 people, including 300 leading scientists, roughly half from outside the government. It comes from the US Global Change Research Program, a team of 13 federal agencies, and is the second of two volumes. The first, released in November 2017, concluded that there is "no convincing alternative explanation" for the changing climate other than "human activities, especially emissions of greenhouse gases."
The report breaks down the possible impact of climate change by US region and looks at the effects climate change will have on health, economy and infrastructure. Here are some of its key predictions:
1. Crop production will decline.
Farmers will face extremely tough times. The quality and quantity of crops will decline across the United States due to higher temperatures, drought and flooding.
In parts of the Midwest, farms will be able to produce only about 75% of the corn they produce today, and the southern part of the region could lose more than 25% of its soybeans.
By 2100, higher temperatures in places like Yolo County, California, could make it too hot to cultivate walnuts. Climate change could also severely limit almond production in California.
2. Cows could have it bad.
Heat stress, which cost the dairy industry $1.2 billion in 2010, will become an even bigger issue, potentially causing average dairy production to fall between 0.60% and 1.35% over the next 12 years.
Livestock for meat could struggle to find plants to graze on, and heat stress could impact their numbers.
3. Food sources from the sea will decline.
There won't be as many oysters, shrimp or crab due to ocean acidification. The report predicts a $230 million loss for that industry by the end of the century. Annual oyster harvests in the Southeast will decline by 46% under the worst-case scenario by the end of the century.
Fish stocks overall may decline as red tides -- algae bloom that deplete oxygen in the water and can kill sea life -- become more common. It was a red tide that triggered a state of emergency in Florida in August.
The coral reefs that support diverse fish life off the Florida Keys are already declining and could be lost in the coming decades due to higher temperatures.
River fish could also die off; higher temperatures have already led to die-offs due to proliferative kidney disease.
Warmer temperatures were a problem for endangered sockeye salmon and Chinook in the Columbia River when they suffered a serious die-off in 2015.
4. Food- and waterborne illness will spread.
Weather that is bad for farmers is good for spreading food- and waterborne diseases, and more people will be exposed to them.
Marine toxins and pathogens will contaminate seafood. The waterborne bacteria Vibrio, which is already causing thousands of illnesses a year, will expand to seafood in northern seas and affect oysters grown in the Northeast.
Floods and heavy rains that can cause sewers to overflow can contaminate drinking water, leading to more stomach problems, studies have shown.
Droughts could cause more skin and eye infections, due to lack of water for personal hygiene. Other waterborne diseases that could spread include hepatitis A, salmonellosis, shigellosis, typhoid and E. coli.
5. Bugs will bug us more.
Weather that's bad for crops is good for bugs.
Mosquitoes and ticks love warmer and wetter temperatures. That means diseases such as dengue, chikungunya and Zika will be more widespread. West Nile cases are expected to more than double by 2050 due to increasing temperatures.
The Northeast could see more cases of Lyme disease as the tick season expands in states like Maine and Pennsylvania.
6. It will be hard to breathe.
Asthma and allergies will also be worse due to climate change. The pollen season will intensify and lengthen in parts of the United States due to warmer temperatures.
Oak pollen in the Midwest will send more people to the emergency room for asthma, costing up to $170,000 annually, according to the report.
Urban areas with higher concentrations of CO2 will see more allergy-causing plants such as ragweed growing faster.
Increased rain in some areas will encourage mold growth indoors, which can make asthma symptoms worse.
7. Mental health will be challenged.
Extreme weather can have serious mental health consequences and lead to post-traumatic stress disorder, anxiety and depression.
Exposure to extreme heat, for instance, is associated with aggressive behavior, suicide, violence and higher admissions to hospitals for people who have a mental illness, studies have shown.
Extreme temperatures can also increase stress levels. Worsening air quality limits the time people can exercise or socialize outside; both activities are big stress relievers, studies have shown.
8. More of us will die.
Higher temperatures will also kill more people, the report says. The Midwest alone, which is predicted to have the largest increase in extreme temperatures, will see an additional 2,000 premature deaths per year by 2090.
People who live in Rhode Island could see an additional 1,500 heat-related ER visits by 2095, and some of those visits will end in death, according to the report.
Poor air quality can also lead to more strokes and heart attacks.
The heat will be a problem for elderly people with chronic conditions, increasing the death rate by 2.8% to 4% with each increase of approximately 1.8 degrees Fahrenheit (1 degree Celsius) in summer temperature.
9. We won't be able to work as much.
The Southeast alone will probably lose 570 million labor hours by 2090.
In the worst-case scenario for farm workers, by the end of the century, high temperatures will add up to a loss of 2 billion labor hours, equating to an estimated $160 billion in 2015 dollars.
In Chicago, it will be a lot harder to work outside when 100-degree days, rare now, become increasingly common. By late century, the report predicts that the city could see almost 60 days a year over 100, making it more like present-day Phoenix or Las Vegas.
10. We won't be able to get around as easily.
Infrastructure is vulnerable to increasing temperatures and wet seasons.
By 2050, the Southeast will have the most vulnerable bridges at risk of failure, and more dams will probably break with increased hurricanes and rain.
The East Coast now has 7,508 miles of roadways threatened by high tide coastal flooding, and that problem will only get worse with climate change.
Train systems like Atlanta's MARTA could fail in extreme rains. MARTA authorities are trying to identify what parts of the system are most vulnerable to climate change and are trying to make improvements before problems start.
11. Water infrastructure will be challenged.
Storm water systems weren't built to withstand the extreme rain that comes with climate change. The cost of adapting urban storm water systems in the Midwest, for example, could exceed $480 million per year.
The total cost to remediate sanitation facility deficiencies to provide safe water and sewers for American Indians in the Northern Great Plains could be around $280 million.
These populations are already vulnerable to climate change. For example, Standing Rock ran out of water during a 2003 drought.
12. Floods will be more frequent.
Charleston is trying to shore things up because it is predicted to have 180 tidal floods per year by 2045, compared with 11 it had in 2014. Each flood event costs the city $12.4 million (in 2009 dollars), studies show.
Other Southeast coastal cities like Wilmington, North Carolina, and Miami and Key West, Florida, have set records for coastal flooding in recent years. High tide flooding poses daily risks to homes, businesses and infrastructure.
Sea level rise and storm surge in the Southeast could cost the region up to $60 billion each year by 2050 and up to $99 billion by 2090 under the worst-case scenario.
More than half a million people in Florida face "extreme" or "high" risk from sea level rise.
13. Wildfires will increase.
Wildfire seasons -- already longer and more destructive than ever -- could burn up to six times more forest area annually by 2050 in parts of the US. Burned areas in Southwest California could double by 2050.
Firefighting costs in the Southwest alone could total $13 billion from 2006 to 2099.
14. History will be lost.
Sea level rise will ultimately wipe out the record of human habitation of the coastal margin in the Southeast within the next one or two centuries, a study has shown.
The Southeast would lose 13,000 recorded historic and prehistoric archeological sites due to projected sea level rise.
More than 1,000 sites on the National Registry of Historic Places are endangered, including forts in Charleston, South Carolina; St. Augustine, Florida; and Savannah, Georgia.
15. There will be more snakes and other invaders.
The predicted freeze-free season will probably lengthen by more than a month in the Southeast. That means a variety of tree-damaging beetles will probably move north and kill trees there.
In the West, bark beetle infestations could spread; they killed 7% of western US forest area from 1979 to 2012 due to warming temperatures, the report says.
In South Florida, the Burmese python will like the warmer temperatures and reproduce more, potentially decimating mammal populations. Rodents that carry disease could also reproduce faster.
Invading Humboldt squid that love deoxygenated water, warmed and acidified by climate change, will prey on fish stocks in the West.
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