Going negative with carbon can be positive for ag

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AMES, Iowa - Eugene Takle would love to see farmers and lawmakers thinking positively about going negative when it comes to carbon.

While the world is still debating the idea of global warming, the faster it can accept and work with the idea, the more Upper Midwest farmers will benefit, says Takle, a professor of agronomy and director of the Climate Science Initiative at Iowa State University.

One reason is such acceptance and action could lead to a greater effort toward designing crops and crop systems for the next century.

Takle spoke at last month’s BIGMAP symposium, “Food and Fuel Crops: Issues, Policies and Regulation.”

He says the sooner the world decides whether to make a commitment to reducing greenhouse gases and sets rules for how to do so, the sooner industry will have some idea of how to react.

He says the emissions of carbon in the world have risen dramatically since the 1950s and argues “business as usual” is simply not an option.

Over the past 25 years, the planet has warmed, Takle adds. But, he says the models point toward an acceleration in that trend in the coming century.

Present modeling points toward a four-degree rise during the 21st century.

Takle also says making changes to reduce carbon emissions will do little to slow that trend until the latter part of the century.

“In the short term, it doesn’t make a whole lot of difference what we do to adapt,” he says.

But, he says it could make a big difference in the second half of the century.

For the region, the most-significant early effect of global warming will likely be more extreme weather events, Takle predicts.

Over the past century, he says there was a 50-percent increase in the frequency of days with precipitation over 4 inches in the Upper Midwest.

Other possible changes in the region include:

- Longer frost-free periods;

- higher average winter temperatures;

- fewer extreme cold temperatures in winter;

- fewer extreme high temperatures in summer in the short term but more in the long-term;

- higher nighttime temperatures in summer and winter;

- more freeze-thaw cycles; and

- increased weather variability.

When it comes to precipitation, the list looks something like this: more annual precipitation, wetter springs and drier summers will be more common, more water logging of soils, more variability in summer precipitation including more-intense rain events.

Also predicted are: Higher absolute humidity, stronger storm systems, more winter soil moisture recharge, snowfall increases in the short-term but decreases in the long-term.

This will mean things, such as erosion control and flood control, will become even more important.

“If this is our future anyway, let’s prepare for it,” Takle says.