Wednesday, May 01, 2019

How climate change is affecting 11 American crops

Peaches are among crops threatened by a combination of warmer
winters followed by late frosts. (Photo by Maura Friedman, NYT)
Consumers may see climate change as a nebulous concept with far-off effects, but agriculture is already seeing plenty of changes. "Warmer temperatures are extending growing seasons in some areas and sending a host of new pests into others. Some fields are parched with drought, others so flooded that they swallow tractors," Kim Severson reports for The New York Times. "Decades-long patterns of frost, heat and rain — never entirely predictable but once reliable enough — have broken down."

Small climate shifts that nudge growing seasons even a few weeks earlier or later can disrupt supply chains, schedules for farm workers, and natural processes like honeybee pollination and pest management. And though higher temperatures make it possible to grow crops in once unsuitable areas, that heat also hurts crops in traditional growing areas, Severson reports.

Here are 11 common food crops, from all over the country, that Severson reports are seeing big changes because of climate change:
  1. Tart cherries have long been grown in northern Michigan, since growers have been able to rely on long, cold winters and slow, cool springs so the trees don't bloom until the threat of a late freeze has passed. But warmer early temperatures, followed by freezes, have caused two total crop failures in the past decade; the last one before that was in 1945. Increasingly violent spring storms have damaged the fruit, and the climate shift has also brought an invasive fruit fly that ruins the cherries.
  2. Organic raspberries are endangered in New York because of too-warm winters that don't kill off fruit flies and other pests. Organic farmers are especially vulnerable to insects since they can't use commercial pesticides. The area has also been seeing either way too much rain (which causes fungus on the fruit) or not enough (which means the fruit doesn't grow).
  3. Watermelon farmers in Florida are planting and harvesting crops earlier. That means they're competing with late-winter crops from Mexico, so American farmers may not have enough Mexican laborers to pick crops, especially with tighter immigration restrictions in place.
  4. Chickpeas are doing well in Montana because of climate change. The average annual temperature has increased 2.4 degrees in the past century, but average rainfall has stayed about the same. That makes chickpeas a good bet, since they require less water than other cereal grains and also improve the soil, but the crop faces global competition. 
  5. Wild blueberries are a rockstar in Maine agriculture, but a longer growing season, warmer summers, erratic frosts, increasing fruit flies, and more frequent droughts are threatening the crop.
  6. Organic heirloom popcorn has been a reliable crop in Iowa for decades, but increasing flooding, tornadoes and other unpredictable weather are making it much harder to grow.
  7. Peaches in Georgia and South Carolina are threatened by increasingly warm winters. Without a certain amount of consistently cold weather, the buds are weak and make poor fruit. Also, too-warm winters followed by frost can kill most buds. A warm winter in 2017 led to the failure of almost 85% of Georgia's peach crop.
  8. Organic apples in Washington are suffering from hotter spring weather, since such weather increases diseases like fire blight. Hotter temperatures can also cause apples to sunburn.
  9. Golden kiwi fruit in Texas are well suited to heat and humidity, but require a certain amount of predictably cold weather to thrive. Erratic spring freezes threaten that. 
  10. Artichokes in California depend on cool, cloudy weather fed by the Pacific Ocean in the spring, but a warming ocean has made such weather less common, and warmer weather in general means more pests.
  11. Rice is notoriously thirsty, and decreasing rain in Arkansas, where almost half the nation's supply is grown, is drying out rice farms and the underground aquifers that help water the fields. Higher temperatures cause more starch content, making rice stickier and more brittle.

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