New Report Outlines Great Lakes Climate Change Impacts on Agriculture
- Farm & Market News
"New Report Outlines Great Lakes Climate Change Impacts on
Urbana , Illinois - Feb. 28, 2005 - There is growing evidence that
suggests climate is changing in the Great Lakes region. Already
winters are getting shorter, annual average temperatures are growing
warmer, the duration of lake ice cover is decreasing as air and water
temperatures rise, and heavy rainstorms are becoming more common.
"There is an extensive amount of evidence indicating that the Earth's
climate has warmed during the past century," said Donald Wuebbles,
head, University of Illinois department of atmospheric
sciences. "Foremost among this evidence are compilations of the
variation in global mean sea surface temperature and in surface air
temperature over land and sea."
The increase in temperature has occurred in two distinct periods. The
first was roughly from 1910 to 1945, and the second has been since
"The 1990s has been the warmest decade on record. And recent state of
the art numerical models from the National Center for Atmospheric
Research suggest that natural variability of the climate is not
sufficient to explain increasing temperatures," said Wuebbles.
He says that by the end of the century, maximum daily temperatures
could rise by 5 to l2 degrees in winter and 5 to 20 degrees in summer
in the Great Lakes region. In addition, the growing season could be
four to nine weeks longer.
Precipitation While current analyses suggest that annual average
precipitation may not change dramatically in the years ahead,
seasonal precipitation in the region could become generally more
extreme with less precipitation in the summer and more in the winter.
"In the Midwest, changes in climate that have already occurred have
produced longer growing seasons and heavier rainfall events," said
Wuebbles. "And according to the latest models, average winter
precipitation across the region will likely increase and summer
precipitation will likely remain the same or decrease."
However, by the end of the century, drought frequency will likely
increase due to the combination of increased summer temperature,
evaporation, and runoff from intense rainfall events, and a decline
in summer precipitation.
Overall, the region may grow drier because any increases in winter
rain or snow are unlikely to compensate for the drying effects of
increased evaporation and transpiration in a warmer climate.
"This drying trend will affect surface and groundwater levels and
soil moisture is projected to decrease by 30 percent in summer. In
addition, the frequency of intense weather events such as 24-hour,
multi-day downpours may increase flooding," said Wuebbles.
The Causes Carbon dioxide is the largest changing concentration of
the greenhouse gases and the one of most concern to scientists
studying human effects on global climate.
"Human activities are primarily responsible for the increase in
carbon dioxide in the atmosphere," said Wuebbles. "Carbon dioxide has
increased because of increased use of fossil fuel and because of land
uses such as those related to deforestation and biomass burning."
Wuebbles says that climate change has the potential to significantly
affect agricultural, ecosystems, water resources, and human health
"All these areas are already under stress because of expanding
population and continued urbanization. Climate change will further
add to these stresses. Policies to address these potential impacts
must be considered," he said.
Impacts Expected for Crop Agriculture
Together, the states of Illinois, Indiana, Michigan, Minnesota, Ohio,
and Wisconsin have more than 380,000 farms, encompassing more than
100 million acres of prime land with a total economic impact of $40
Farmers in the region are already experiencing wetter spring and fall
weather and more intense rainstorm events. These trends will continue.
"Later in the century, the region's climate will grow considerably
warmer and probably drier in the summer. By the end of the century,
the region's climate will be quite different than it is today," said
Michelle Wander, University of Illinois Associate Professor of soil
Wander drafted the agricultural portion of the Union of Concerned
Scientists publication Confronting Climate Change in the Great Lakes
Region. The full report can be found at www.ucsusa.org/greatlakes/.
"These changes will dramatically affect how the climate feels to us.
By 2030, Illinois summers may resemble those of Oklahoma or Arkansas
in terms of average temperature and rainfall. By the end of the
century, however, the Illinois summer climate will generally resemble
that of current east Texas. Winters will also change, albeit less
drastically. By century's end, they may be warmer and drier, much
like current-day Oklahoma," Wander projected.
Yield Reducing Trends In general, using current climate comparisons,
Great Lakes agriculture must prepare for climate conditions marked by
extreme summer heat, summer drought, and spring and winter flooding.
"Farmers in the region are already experiencing wetter spring and
fall weather and more intense rainstorm events. In addition, farmers
are challenged by changing technology and markets. These trends will
continue and are likely strengthen," said Wander. Wander says that
too much water at the wrong time leads to waterlogging and delayed
planting. "On the other hand, four days of ill-timed soil moisture
stress can reduce corn yields by 50 percent, and soil moisture stress
already limits soybean yields."
She says also that responses to moisture surpluses and deficiencies
will increase production costs. Wet fall weather, for example, would
increase the need for crop drying, and midsummer drought would
increase the number of acres requiring irrigation. Such shifts will
impose additional costs on farmers and increase tensions over limited
Extreme events such as severe storms and floods during the planting
season are likely to depress yields, too.
"Soybeans are particularly vulnerable to climate variability.
Perennial crops such as fruit trees and vineyards are also vulnerable
because adjustments cannot be made as flexibly, putting long-term
investments at risk. And the combination of flooding and high heat is
especially lethal to both corn and soybeans," she said.
Another factor in the climate change projections is an increase in
atmospheric carbon dioxide.
"Projections for soybeans, which are generally positive and
attributed to both the CO2 fertilization effect and earlier planting
dates, suggest increases in yield in the central and northern
portions of the region but losses in southern areas. Soybean yield
variability, however, is also expected to increase. Enhanced wheat
yields of approximately 20 percent could result from these combined
factors, but wheat production is likely to be limited by competition
for land from other crops, including soybeans."
However, these yield increases may be offset or negated by rising
ozone concentrations that result from human activities such as the
application of nitrogen fertilizers and burning fossil fuels.
"Ozone is particularly damaging to soybeans and horticultural crops,
and soybean yields in the region are already reduced approximately 25
percent by ozone damage. But high heat and associated heat stress
will also reduce corn yields in the south and western parts of the
region," said Wander.
Crop Pest Problems Climate changes will also affect the outlook for
damaging crop pests.
"Leaf-chewing insects and aphids are stimulated by elevated carbon
dioxide. Higher temperatures, particularly in spring and summer,
accelerate the number of generations of harmful multi-generational
pests such as soybean and corn leaf aphids, potato leafhoppers, and
two-spotted spider mites. Ranges for many pests, including bean leaf
beetles and corn borer, have already expanded northward."
Also, milder winters enhance survival for some pests such as bean
leaf and corn flea beetles. A hot, dry summer may exacerbate yield
losses from corn rootworm larvae. Excess moisture and humidity can
increase the frequency of gray leaf spot, crazy top, and smut in
corn; later in the century, drought will likely increase the damage
inflicted by soybean cyst nematodes.
On the other hand, extremes in temperatures and precipitation at
important insect growth stages may reduce the threat of some pests
such as western corn rootworm or European corn borer. The
interactions of extreme weather events and insect reproduction,
survival, and success are complex and must be evaluated on a species
by species basis. Water Resources Agriculture's impact on the
region's water resources is already a concern due to chemical
contamination of ground and surface waters. As climate continues to
change, these concerns will intensify.
"More intensive production in the region's northern areas may require
the use of more chemicals and nutrients. Increased flooding and more
frequent extreme rainfall events will worsen soil erosion and
introduce more agricultural chemicals and animal waste into the water
supply," said Wander.
She says that farmers' costs to maintain soil fertility and
municipalities' costs to preserve or restore safe drinking water are
likely to increase.
"Eroded sediments and water runoff degrade streams and wetlands,
reducing food and habitat for migratory birds and waterfowl. That, in
turn, affects bird-watching and hunting activities, too."
Policies Can Reduce Heat-Trapping Emissions The Environmental
Protection Agency estimates that agricultural activities were
responsible for nearly seven percent of total U.S. heat-trapping
emissions in 2001. This estimate does not include carbon dioxide
emissions from on-farm energy use, but does include methane and
nitrous oxide emissions, which are also potent heat-trapping gases.
The good news is that practical solutions exist today for agriculture
to reduce these emissions.
"Along with helping to address the growing problem of climate change,
many of the solutions discussed below would also reduce soil erosion,
improve air and water quality, increase biodiversity, and generate
economic benefits," said Michelle Wander, University of Illinois
Associate Professor of soil fertility.
Wander and Steve Clemmer of the Union of Concerned Scientists
collaborated to develop policy recommendations that would heat-
trapping emissions. They recommend increased funding for energy
efficiency and renewable-energy projects.
"Over the past two years, the USDA has provided $44 million from the
Farm Bill to support 280 renewable-energy and energy efficiency
projects on American farms. Projects funded in the first year alone
will produce enough electricity to supply the annual needs of 30,000
households while creating 1,300 new jobs and reducing carbon dioxide
emissions by more than one million metric tons over the life of these
projects," said Clemmer.
He notes, however, that the USDA has, in the past, denied proposals
for dozens of other projects due largely to insufficient funding.
Congress should increase funding levels, and states should offer
incentives or tax credits to supplement these funds.
Certain best practices in soil management such as no-till, reduced
tillage, and crop diversification including the use of cover crops
could enhance short-term soil carbon storage.
"Effectively managed soils could abate an estimated 10 percent of
heat-trapping missions produced in the United States over the next 30
to 50 years. Additional funding should be made available from the
USDA's Conservation Reserve Program, Natural Resources Conservation
Service, and other programs to encourage such practices," said Wander.
Wander recommends expanding programs to reduce nitrogen fertilizer
"Best practices to achieve this goal could produce significant
reductions in heat-trapping emissions while lowering nitrate
contamination of water supplies," said Wander.
For example, Wander says between 1985 and 1995, Iowa had several
projects in place that reduced fertilizer use by more than two
million tons, saved farmers $363 million, and reduced heat-trapping
emissions by 10 million tons per year without affecting corn yields.
Several states and the Environmental Protection Agency offer
incentives and programs to reduce methane and nitrous oxide emissions
from livestock and livestock waste.
"For example, Haubenschild Farms, a 1,000-acre dairy farm in
Minnesota, received state and federal assistance in 1999 to install a
manure digester that converts methane into enough electricity to meet
the needs of the farm and an additional 75 homes. The 750-head dairy
generates nearly $81,000 per year from electricity sales and saves
$4,000 per year in heating costs. These savings should recoup the
initial $355,000 investment in five years or less," said Clemmer.
Wander also recommends incentives to sequester carbon on marginal
"Converting one million acres of marginal lands into native forests
and planting 200,000 acres of riparian zone buffer strips with native
trees or grasses such as switchgrass could reduce carbon dioxide
emissions by an estimated 7.3 million tons per year. Additional
funding should be made available from the USDA's Conservation Reserve
Program, the U.S. Forest Service's Forest Legacy Program, and other
programs," said Wander.
It would also be wise to establish renewable energy standards for
electricity and transportation.
"Such standards are a popular and effective means of creating markets
for clean energy produced on the farm. Standards requiring electric
utilities to supply a portion of their electricity from renewable
sources such as wind and bioenergy have already been established in
18 states including Minnesota, New York, Pennsylvania, and
Wisconsin," said Clemmer.
He says a Union of Concerned Scientists study found that a national
standard that would require utilities to provide 20 percent of their
electricity from renewable sources by 2020 would create 355,000 new
jobs including 30,000 in agriculture; save consumers $49 billion on
their electricity and natural gas bills; and reduce the projected
growth in power plant carbon dioxide emissions by 59 percent.
Clemmer says competition from renewable energy would also lower
natural gas prices, thereby lowering fertilizer prices.
In Illinois, there is a growing interest in renewable energy sources.
Governor Rod Blagojevich, in his 2005 State of the State Address,
announced a goal for each electric utility to generate 8% of its
electricity from renewable energy sources. The goal is to help create
jobs, protect the environment, and promote energy independence.
Source: Michelle Wander, 217-333-9471, mwander@...
News writer: Gary Beaumont
phone: 217-333-9440; email: beaumont@...