Ag forum looks at climate change

By Larry Dreiling

"From Colorado to the Clouds: Agriculture and a Changing Global Climate" was the theme of the 2007 Colorado Agricultural Outlook Forum, held recently at Denver.

About 400 persons attended the daylong event.

A host of mostly Colorado-based researchers offered their thoughts about climate change and ways agriculture can play a part mitigating it.

William Cotton, professor of atmospheric science at Colorado State University, delivered the keynote address.

"When I was asked to speak here, I thought I'd be expected to present an Al Gore PowerPoint presentation," cotton said, referring to the former vice president's Oscar-winning documentary "An Inconvenient Truth."

"That ain't going to happen."

Instead, cotton took the forum attendees on a dizzying PowerPoint presentation of his own, one more suited for a seminar to scientific academe than the policy-oriented crowd.

cotton used words like "anthropogenic aerosols" (that's pollution like sulfur dioxide from vehicle and power plant emissions) to describe things that may cloud the sky, keep the sky from doing its job of not just heating, but cooling the planet.

"Global warming

is a fact"

cotton estimated that because of pollution, there are less upslope conditions in the atmosphere to create rain clouds, creating as much as a 4 percent reduction in moisture in places across the northern hemisphere over the last 100 years.

"The presence of pollution removes precipitation," from clouds, cotton said.

Concurring with cotton somewhat was Dr. Dennis Ojima, interim director and senior research scientist at CSU's Natural Resources Ecology Lab.

Ojima also said warming is greatest at high latitudes

"The amplification of warming is due to the decrease of albedo, or the melting of snow and ice," said Ojima. "Global warming is a fact."

Ojima offered numerous studies showing the planet has warmed about 0.74 degrees Celsius over the last 100 years, with two-thirds to three-fourths of it caused by anthropogenic aerosols.

"It's safe to expect 2 to 4 degrees Celsius global warming (more or less regionally) by the end of the 21st century. Relative to the past, this change has little precedent," Ojima said. "It is enough to drive at least 18 to 35 percent of the terrestrial species on the planet to extinction."

It will be hot enough to add enough extra hot days to the calendar, with Ojima estimating a dramatic increase in days above 100 degrees Fahrenheit.

Coping strategies

Ojima then began what became the tone for most of the rest of the day: Identifying coping strategies in light of climate change. Ojima believes:

--Citizens need better preparation for extreme events.

--There needs to be more diversification of land use practices to take advantage of opportunities and to reduce vulnerabilities.

--Water conservation strategies must be developed.

--Methods to increase soil organic matter to increase the soil's water holding capacity must be used more extensively.

--Regional strategies for adaptation to climate change must be developed.

--Develop better communication at all levels.

"As citizens we need to do what we can to reduce emissions," Ojima said. "It will take a global effort to reduce the carbon footprint we've made."

Looking for ways to find opportunities in greenhouse gases was Keith Paustain, a professor in CSU's soil and crop science department.

Globally, agriculture and overall land use, account for about one-third of the warming effect from the increase in greenhouse gases, Paustain said. The U.S. share of that increase is about 8 percent.

Increasing carbon

A way for agriculture to mitigate the problem, Paustain said, is through carbon sequestration in the soil as a way to reduce damage from nitrous oxide and methane discharges.

"Practices that increase soil carbon also improve soil fertility and health, reduce erosion and improve water quality," Paustain said. "Practices to reduce N2O and CH4 also save fertilizer, improve water quality and aquatic habitat, improve air quality through manure management, and may provide renewable energy through biogas from manure."

Paustain estimates the potential mitigation through carbon sequestration could sink anywhere from three to five million metric tonnes of carbon back into environment annually

"Agriculture is a significant emitter of greenhouse gasses but can play a major role in mitigation, reducing total U.S. emissions by five to 14 percent," Paustain said. "Opportunities exist for additional reduction of N2O and CH4, however, achieved mitigation will strongly depend on national and state policies as well as 'competition' with other emission reduction options. Ongoing research will help refine these estimates and produce tools that can help in decision- and policy-making arenas."

Biomass crop fix

Another way to reduce global warming and improve farmer income is through the production of biomass crops. Examining howimportant biomass crops will be was John Sheehan, senior strategic analyst at the National Renewable Energy Lab, Golden, Colo.

"How much biomass is there now and in the future? Today's technology is limited. In the long run, it depends," Sheehan said.

Sheehan estimated an increase in the use of biomass crops for fuel somewhere in the "four-fold range."

"At the high end, available biomass energy that is equivalent to 80 percent of current on-road energy demand--but that's before energy losses to produce the fuel."

Sheehan quoted National corn Growers Association estimates that the upper limit of corn ethanol production at 11 to 17 billion gallons per year.

"Planned capacities for biodiesel and corn ethanol are stretching the limits of supply," Sheehan said. "Even if these plans are realized, they represent a small fraction of current demand."

More reasearch needed

The technology for making biofuels from cellulosic biomass has yet to be demonstrated at a commercial scale, and could be five years away," Sheehan said.

"More R and D is needed to turn this into an industry comparable in efficiency to today's petroleum refineries. Plus, an industry that looked good at $2 per bushel corn looks different at $4 per bushel corn."

Sheehan added several quality of life issues may pressure the biofuels industry in the long run.

"The food versus fuel debate is alive and well. Pressure on agricultural prices could create real economic and ethical--a.k.a political--pressures to hold off on this industry," Sheehan said. "The long-term benefits of cellulosic biofuels could mitigate this price pressure--but the commitment to research is needed.

"We also have to look at water in this equation. Biofuels production can use on the order of five to seven gallons of water for each gallon of fuel produced--and that doesn't count water for irrigation."

Sheehan, who lab is studying all forms of renewable energy, including solar and wind power, urged caution as the issues of biofuels move ahead.

"We need to be making deliberate choices about trade-offs here. There are real benefits, but also choices we'll need to make," Sheehan said. "That means having an ethic of sustainable development. It means doing our homework. We need to seek holistic solutions to climate change and energy security in transportation.

"Biofuels is not 'the' answer. It is one answer, however."

Larry Dreiling can be reached by phone at 785-628-1117 or by e-mail at ldreiling@aol.com.

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5

3/12/07

3 Star CO

Date: 3/8/07

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