AILSA CHANG, HOST:
The warming climate is an increasing problem for agriculture. Even in a good year, one without lots of heat waves or floods, slowly rising temperatures are making it harder to grow food. As part of our summer series on heat, NPR's Laurel Wamsley looks at its impact on apples.
LAUREL WAMSLEY, BYLINE: Harvest time is months away in Sparta, Mich. But walking through his orchard, fourth-generation grower Phil Schwallier can already tell which apples he won't be able to sell.
PHIL SCHWALLIER: Got a little sunburn on it.
WAMSLEY: That's right. Apples can get sunburned.
SCHWALLIER: Yellowish color developing here on the part that's facing the sun. That's just from Friday, Saturday and Sunday when it was so hot.
WAMSLEY: Too much heat can also mess with an apple's color. If nights don't cool down enough for their pigment to fix in place, apples won't turn that nice shade of red that consumers like. And then there can be damage when apples start growing only to be hit by frost.
SCHWALLIER: This is Russet that's growing down the side of the fruit, and this is a defect. I have to throw it out.
WAMSLEY: In fact, any sort of blemish and that apple never makes it to that shiny pyramid in your grocery store. Instead it will be turned into juice or applesauce, for which growers are paid just a fraction of what they'd get otherwise. Schwallier says he's noticed more defects as the climate has warmed. For 150 years, western Michigan has been the perfect place to grow apples, says Jeff Andresen, professor at Michigan State University and the state climatologist. Lake Michigan to the west has moderated the climate, but now...
JEFF ANDRESEN: What you can see in general is less ice for less time on the lakes than used to be the case in past decades.
WAMSLEY: And less ice means that spring comes sooner. That affects the growth patterns of not just crops but also the insects that can destroy them.
ANDRESEN: If we have a warmer climate, they're going to develop faster than they have in the past. An insect pest like codling moth - maybe we have to deal with three generations of that pest in a growing season. Historically, we've typically only had to deal with two.
WAMSLEY: Which means that many growers will spray a third round of pesticide closer to when the apples are harvested. It's not just apples that are affected by all of this. Higher temperatures are reshaping the entire agricultural landscape, drawing a new map of what can grow where. Jim Byrum heads the Michigan Agri-Business Association.
JIM BYRUM: Michigan used to produce more dry beans - navy beans, kidney beans, black beans, things like that - than any other state in the union. We're seeing that industry move west and north. And that's because of climate change. Some of the biggest production increases in corn acres, for example, the last few years have been in states like North Dakota when historically they didn't produce corn.
WAMSLEY: So for some farmers, the warming climate means a longer growing season and new crops. But for most, it just means more unpredictability. Sometimes it's too hot. Sometimes it's too cold. There can be drought or huge rains. All of that creates more risks that growers must protect against. And that's expensive, says Gregory Peck, a professor of horticulture at Cornell University.
GREGORY PECK: Not only do you need to invest in irrigation to be able to survive through those years of drought, but you're also going to need to install more drainage lines for those years when we have excessive rainfall.
WAMSLEY: Apple grower Phil Schwallier has all the latest technology to protect against weather's extremes - irrigation for dry spells, nets to protect against hail and wind, and tall fans that can blow warmer air toward the ground on cold nights when it could frost.
SCHWALLIER: When we plant an orchard, it's such a major investment that we're going to be living with that orchard for, like, 10 or 20 years before we take it out. So we have to be careful on what we plant, what we choose.
WAMSLEY: And on this hot, sunny day, workers on his farm are protecting that investment, spraying his Honeycrisps with calcium carbonate. It's sunscreen for apples. Laurel Wamsley, NPR News, Sparta, Mich.
(SOUNDBITE OF BILL FRISELL'S "DISFARMER THEME")
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