June 2, 2016
Cherkauer is an engineer, not a meteorologist. He can't tell you if it will
rain tomorrow. That's weather. But Cherkauer, an expert in hydrology at the Purdue Climate Change
Research Center, thinks he knows what kind of conditions Midwest farmers
will be facing in a hundred years.
"A lot like 2015, with wet springs and hot, dry summers," he says.
That's climate—how conditions develop over a long time.
In 2015, extreme weather events widely attributed to climate change were
headline news. Globally, it was the warmest year in history, breaking the record
set just the year before. Deadly heat waves were reported in India, Pakistan,
Iraq, Iran and throughout Europe; floods in Ghana and Myanmar; droughts in
Brazil and California. Unprecedented and unpredictable weather roiled
agricultural markets and raised fears of a potential long-term threat to the
global food supply.
Back home, Indiana had its wettest two-month period on record in June and
July, followed by near-drought conditions in August and September. Fields that
were flooded in spring were parched by late summer.
Farmers increasingly are finding that they have either too much water or not
enough of it.
"We need to be planning for water use," Cherkauer says. "The question is, how
do we better manage our water resources?"
Farm Water Could Be a Key to Preserving Water
Weather and Climate
Weather patterns can change noticeably over short periods, especially in
years such as 2015 when strong El Niño or La Niña systems add to the atmospheric
instability. Climate change happens gradually and almost imperceptibly to
Researchers say the trend is real and unmistakable.
"The climate is already changing," says Jeffrey
Dukes, Purdue professor of forestry, natural resources and biological
sciences and director of the Climate Change Center. "Temperatures have increased
quite a bit over the last century or so. Precipitation is changing, too."
It isn't just the amount of precipitation, it's how—and when—it's falling.
Dukes expects the number of significant precipitation events—more than 2 inches
of rain or snow at a time—to double or triple over the next 100 years, mostly in
the winter and spring.
Extreme precipitation at planting time is especially problematic.
"With the warmer weather we are expecting, getting a longer growing season
should be good," Cherkauer says. "But a lot of fields last year were left fallow
simply because farmers could not get into their fields because of all the rain
we had in the spring. If your tractor is sinking up to its axles in mud and you
can't get your crops planted, you can't use that extra time."
The biggest deluge in 2015 came when crops should have been in their prime
On July 7, central Indiana was hit by a storm that drenched the area with
4.43 inches of rain—about equal to the area's average for the entire month. For
the month of July, Indianapolis recorded 13.14 inches of rain, a record and
nearly 9 inches above normal.
"We're looking at more heavy rainfall events and longer droughts," Dukes
says. "In the short term, the next 30-40 years, some crops may actually grow
better. But the negatives are likely to start overwhelming the positives as time
Excess and Deficits
Mark Twain once said everybody talks about the weather, but nobody ever does
anything about it. That's not entirely true. Farmers choose their crops and seed
types based on the weather conditions forecast for the growing season. Investors
establish market prices anticipating favorable or poor growing conditions.
Agribusiness professionals are accustomed to planning for weather variability
from year to year. Now they might have to start dealing with more precipitation
in the spring, which is already the wettest time of year, and even drier
conditions in summer, when crops' water needs are highest.
Purdue professor of agricultural and biological engineering, is leading a
five-year, $5 million federally funded project to determine how farmers could
store water when they have it to use when they need it.
"Drained lands comprise at least 50 percent of Indiana's cropland, including
some of the most productive lands in the state," Frankenberger says. "These can
experience both water excess and water deficit in the same year, which is what
happened last year. Storing drained water within the landscape could increase
the sustainability of water for agriculture, particularly as intense rainfall
and prolonged summer drought are expected to increase under future climate
Frankenberger and her team are looking at three specific practices: drainage
water management to keep moisture in the soil longer and thereby maximize its
effectiveness; saturated buffers to slow the outflow of water; and water
recycling, in which subsurface drainage water is stored in ponds and then
irrigated back onto the crops.
"There might come a day when farmers view excess water in the spring not as a
waste to be disposed of but as a valuable resource to be saved in order to
reduce the risk of water-stressed crops later in the season," Frankenberger
Modeling the Future
For now, it remains difficult to say when that day might come.
Researchers rely on climate and crop models to determine what the future will
hold, but the recent rash of extreme weather has rendered many existing models
obsolete. Scientists are working to develop new models that can account for
unprecedented swings in climate.
"None of the current crop models are really good at extremes," Cherkauer
says. "What we need to be working on is a future design that brings in
resiliency and flexibility and accounts for what's happening in soil and
All of this will have a noticebale impact on crops, Cherkauer believes, but
there is no way to tell just yet what that will be.
"We'll likely see corn yields consistently reduced and soybeans generally
higher," he says. "These might not be huge changes, but it's more like a 10-day
weather forecast. We don't know the specifics, but our research can provide
guidance on what to expect and how to make agriculture more resilient to climate