Last Wednesday morning at 6 a.m. when I started writing the newsletter, the temperature here was 38 degrees — a record for the date Today the forecast high is 100 degrees, which will also be a record if it verifies.
While it’s not a tornado or hurricane, this 60-plus degree temperature variation in the space of a week is extreme. From an agricultural perspective, it is very close to the limit of what most crop plants can survive. Broadly speaking, crops that can tolerate freezing temperatures cannot tolerate excessive heat — and vice versa.
For most farmers in California’s Central Valley, the dry weather and continuing drought are the biggest concern. Very few crops can be grown without water, and millions of acres have been fallowed as supplies from many reservoirs have been reduced or cut off completely. The drought has certainly garnered extensive and increasing coverage in the media, especially as it is beginning to impact homeowners through water restrictions. But spring 2022 has also featured multiple, distinct, widespread freezing events that have impacted almost every crop grown here. And these freezes have generated virtually no media coverage.
In February, almond growers in counties up and down the state lost their entire crop when the blossoms froze repeatedly over three nights. That same event destroyed an estimated 20% of California’s peach and nectarine crop, but Terra Firma’s loss was closer to 80%. That freeze event came just days after a heatwave set daily records for high temperatures.
Another freeze in early April that wiped out thousands of acres of winegrapes in our area also damaged walnuts, pistachios tomatoes and other crops around the state. We got lucky that time, seeing only a small amount of damage to our grapes and none to our tomatoes, peppers, or watermelons that would have been destroyed if it had gotten just a little colder here.
But the record-setting temperatures last Tuesday night — May 11th — were possibly the most alarming. Growers around the valley reported seeing temperatures as low as 33 degrees. Just about all the crops grown in the valley are planted by that date, and a hard freeze of 32 would damage or destroy just about all of them.
Even within agriculture, experts are still developing their understanding of how extreme weather will effect each crop. Historically, devastating freezes have been uncommon and isolated, making it hard to study them in detail. Exact data is often unavailable. For many crops, it is still not precisely understood how much cold they can tolerate and at what stage in their lives.
But one thing is certain: unseasonal cold weather can kill not just specialty crops but those that “feed the world”, including corn, beans of all kinds, and potatoes. I’ve asked climate scientists directly why they don’t seem concerned about cold weather damage to crops. Their answer seems to be “it doesn’t fit the narrative” of ever-hotter temperatures — which can also kill crops.
The bigger story is that our food supply depends on a fairly narrow range of weather outcomes happening during established, predictable growing seasons. That scenario, which has allowed humans to feed ourselves by farming for thousands of years, is by no means guaranteed in the uncertain future that climate change presents. And even if enough food can be produced in that future, who will grow if farmers cannot reliably earn an income on an annual basis.