Climate Change
Could Lengthen Season

By Karen Gentry
Managing Editor

Warmer and wetter - that’s the general consensus of researchers, scientists and meteorologists for the climate of the Great Lakes in the coming century.

Scientists generally agree that the earth will warm by up to 5°F or more in the next century and most growers will notice this difference in their lifetime, according to Jeff Andresen, assistant professor in agriculture meteorology at Michigan State University (MSU). Andresen was one of 10 speakers at “Climate Change and Agriculture in the Great Lakes Region,” a workshop sponsored by the Environmental Protection Agency at MSU in March.

“The ag industry is very dependent on weather and climate,” Andresen said. He said the conference brought together a cross section of 60 people including growers, who openly discussed a lot of hypothetical “what ifs?”

“If this change occurs in a very orderly fashion then the industry (agriculture) will probably be able to adapt,” said Andresen. Warmer and wetter would translate into a longer growing season for states in northern latitudes, which is a good thing, Andresen said. For growers this could mean more choices of varieties and new crops to grow.

Andresen cautioned if the frequency of extreme events increased then “all bets would be off” making growing some crops an impossible task. Highs in the 80s in April followed by frost and wind freezes, like Michigan experienced this year, is an example of an extreme event. Andresen noted that scientists have no idea why these extreme events are happening and are just beginning to study them. He said scientists disagree about whether variables in the weather are a natural occurrence or caused by human activity.

Lonnie Thompson, a glaciologist from Ohio State University, said glaciers are receding in response to an increase in global temperature. This is mainly caused by the burning of fossil fuels that release carbon dioxide (CO2) into the atmosphere and trap the sun’s heat, creating a phenomenon known as the greenhouse effect. Global temperatures have increased eight-tenths of a degree over the last 100 years.

“That increase may not seem significant,” said Thompson, “but when you take into account the amount of CO2 that has been released over the last century, the impact of the climate change on Earth is substantial.”

Thompson, named one of Time magazine’s top 20 scientists, discussed the recession of glaciers and the impact global warming will have on agriculture at the Conservation Tillage and Technology Conference in Ada, Ohio in February.

“Glaciers are our best tool for studying natural climate variations. They respond to what’s happening to the environment and there is compelling evidence to suggest that they are rapidly disappearing,” said Thompson, who works at the Byrd Polar Research Center.

Most agree that there are increasing levels of carbon dioxide (CO2) in the atmosphere. Andresen said these higher levels of CO2 create more dry matter in plants.

“It’s easier for the plant to make dry matter. For most crops we think that’s also a positive,” Andresen said.

Although a longer growing season may translate into more options for growers there may be more pests and weeds to worry about, according to Andresen. He said fruit growers typically have two generations of the apple codling moth to deal with while a longer growing season may mean three or more generations to deal with.

“If crops are happy, so are weeds,” Andresen said. He noted that growers could be faced with exotic pests and weeds that have never been a problem before.

“The real world is a very complicated place,” he said, noting that there are many different dimensions and possibilities.

Global warming would mean winners and losers. Andresen said the middle and high latitudes would definitely benefit while some low latitudes “would physically just become too warm to support some types of agriculture,” he said. Andresen noted that countries like Canada and Russia would benefit from a warmer climate.

Andresen said a great deal of discussion took place at the conference. “Nobody said this is a bunch of rubbish,” regarding the consensus that the earth is getting warmer.

Water as a finite resource was a topic of conversation. “For most crops water is the single most limiting factor,” said Andresen.

Thompson said that whether a Midwest state like Ohio might face wetter conditions similar to those experienced in North Carolina or a drier climate like that of northern Texas remains to be seen.

Thompson said sustained high temperatures could be detrimental to the health of livestock as well as people. Thompson noted that in July of 1995 when temperatures rose to 104°F over 600 people died in Chicago.

Potential Impact on Potatoes
“I look at wet as being a benefit; I don’t know about warmer,” said Howard Viegelahn, Viegelahn Farms and Investments in Northeast Michigan, one of the conference speakers. He said that very little irrigation was needed when he started in potato seed production 30 years ago. “Today we run currently under 18 pivots. It’s not only a supplement now, it’s almost a necessity,” Viegelahn said.

He said a change in climate would shorten up the window when they have to move all potatoes. Viegelahn told the audience that a warm-up in April and May makes a difference in long-term storage, critical for the important chip industry. He believes he needs to start considering air conditioning.

He told the audience he’ll probably begin planting earlier than normal, taking the risk of frost early rather than the extensive heat in August.

Climate Impact on Wine Grapes
Doug Welsch, president of Fenn Valley Vineyards and Winery in Fennville, Mich. told the audience that as a winemaker he has take a very long-range look because of the expense of replanting.

“My crop spends 25 years in the ground. It takes five years to come into bearing and it will continue to produce fruit for another 20-25 years,” said Welsch.

He said that a warmer winter might translate into the ability to grow more cold-sensitive varieties. Welsch noted that increased variation in temperatures would offset any increased minimum temperatures during the dormant period. At bud break variability is a very crucial element. “If you get a false spring followed by a cold spell, we lose our entire crop,” he said.

A warmer climate mean grapes will ripen earlier and there’s a whole different flavor profile, according to Welsch.

“Grapes that do well, make good wines by ripening during one period, may not do as well in an earlier period, given the vines I have in the soil,” Welsch said. He told the audience that a warmer growing season makes better red wine.

Welsch said consistently warm winters will enable him to plant varieties that are found in southern Europe. As consumers’ taste preference shift from white to red this is a positive impact.

Impact on Fruit Crops
Jim Nugent, coordinator of the Northwest Michigan Horticulture Research Station, said that a very slow onset of winter and many temperatures above freezing, causes more winter damage. Most prone to problems of winter injury would be wine grapes, peaches and sweet cherries. With a warming trend, buds develop earlier. He told the audience that tart cherries bloom the first week of May compared to May 18-21 about 26 years ago.

Weather extremes with earlier development followed by cold events will be a problem especially for tart cherries, sweet cherries and apricots, according to Nugent.

Warmer temperature means there will be the need for more water that would be offset with increased rainfall. “If we don’t’ get the offsetting rain, I see an increased need for irrigation,” said Nugent.

In his region in Northwest Michigan, Nugent believes increased heat will help the Michigan wine industry and hurt tart cherries. He said tart cherries love the cool climate and they’re very prone to spring bud damage.