Farmers adapting to climate changes
ALTOONA – A variety of subjects were covered during a farmland owner’s workshop held at Iowa State University Extension’s Polk County office last week.
A large crowd of farmland owners and operators were in attendance to learn more on what changes are ahead for their land values and to help them prepare a plan.
Gene Takle, director of the Iowa State University climate science program, told how global climate change could eventually affect Iowa farmland.
“Climate science can now be used for decision-making,” said Takle.
A large factor to ever-changing climate, Takle said, is the large increase in carbon dioxide in the earth’s atmosphere.
According to Takle, carbon dioxide levels are at the highest they have been in more than 400,000 years.
A warmer globe
Takle said there are natural causes to the earth’s warming, such as the greenhouse effect. He said this is 100 percent natural by keeping heat trapped in the atmosphere.
This greenhouse effect is what sustains life on earth, he said, and keeps the average temperatures at 55 degrees rather than the potential 20 degrees if there were no greenhouse gases.
The enhanced greenhouse effect, otherwise known as global warming, is primarily human-induced, according to Takle.
“We’re increasing heat-trapping gases in the atmosphere,” he said. “It’s like wrapping an extra blanket around the earth.”
One particular non-natural mechanism affecting our climate is carbon dioxide.
There are 10 indicators of a warming world. Those includes increases in water vapor, air temperature near the surface, air temperature over the ocean, sea surface temperature, sea level, ocean heat content, temperature over the land, decreased sea ice, diminishing glaciers and snow cover.
Takle said last month was the 376th consecutive month with global average temperature above the 20th Century average.
“We are on a climb the warming has not reversed,” said Takle.
He added that solar radiation has fluctuated within historical limits, so the sun shouldn’t be to blame.
“Natural processes are not the major contributors to recent warming of the globe,” said Takle. “Increases in heat-trapping gases are the only explanation.”
Takle said during La Nina events, when temperatures may drop for some time, many will begin to dismiss the possibilities of global warming, but advises those are only temporary events.
“Every time we have an El Nino, the temperature goes up, and with a La Nina, they may go down for a few years, but we need to keep looking more long-term at the temperatures,” he said.
People will argue there is no such thing as global warming, but in his opinion, using scientific principles to create climate predictions, are proving otherwise.
Scientific principles, he said, include Newton’s laws of motion; law of conservation of energy; the law of conservation mass and equation of state.
“These are the same principles that have been used to design, build and operate airplanes and nuclear power plants as well as predict, in advance, the conditions astronauts would encounter on the moon,” he said. “These are laws we have confidence in.”
“We have used these to make projections of our climate in the future.”
Depending on emissions of greenhouse gases, Takle said some scenarios are showing a range of projections that our temperature could be rising 3 to 6 degrees Fahrenheit in less than 100 years.
“This is all due to massive use of fossil fuels and increased greenhouse gases,” he said.
Another project, Takle said suggests a much higher likelihood of a 1-meter rise in sea level by 2100. This rise, he said, could take away the Florida Keys.
“A one-meter rise will be hard to avoid possibly within this century just from thermal expansion,” he said.
Increases in very high temperatures will have wide-ranging effects, Takle said, including in Des Moines. He said the city is currently recording an average annual 1.4 days a year of temperatures exceeding 100 degrees.
Projections are showing that is going to rise dramatically, Takle said, with a potential of 30- to 60-days of temperatures reaching more than 100 degrees by the end of the century.
“That’s substantial warming,” said Takle.
Along with increased heat, Takle said precipitation for 2081-2099 shows increased winter and spring precipitation with drier summers. These water events will come he said in more frequent and intense periods of heavy rainfall.
Extreme weather events are already becoming more common, he said. Weather events we are seeing now will most likely become commonplace.
Heat waves will likely become longer and more severe; droughts are likely to become more frequent and severe in some regions, while there could likely be an increase in severe thunderstorms and perhaps tornadoes in other regions.
Winter storm tracks are shifting northward and the strongest storms are likely to become stronger and more frequent.
“These extremes are already showing up in our records,” said Takle.
These larger weather events could potentially be causing some conservation issues with erosion.
Takle said typically a rainfall bringing more than 1.25-inches increases the likelihood of an erosion-creating event, meaning run-off and ponding.
There has been a shift in seasonability with rainfall recharge in the spring. This is, and will continue to have, huge agricultural implications, according to Takle.
“For every 1 inch of rain, we lose two-and-a-half days of work in the spring,” he said. “We have already been losing field days.”
Takle said Iowa agricultural producers believe in climate change and have already begun making adaptations.
These adaptations to climate change include:
A). Dealing with a longer growing season by planting longer-season hybrids earlier and harvesting later.
B). Wetter springs. Producers have already started buying larger machinery which enables planting in smaller weather windows.
C). More summer precipitation has called for planting higher densities for higher yields.
D). Wetter springs and summers means more subsurface drainage tile is being installed.
E). Higher humidity. More spraying for pathogens is required with more humid and wet conditions leading to crop dry-down issues.
F). Producers have increased their size of bean heads for a faster harvest due to a shorter harvest period during the daytime because of the higher humidity shortening the harvesting day.
G). Drier autumns. Farmers have been delaying harvest to take advantage of natural dry down conditions.
“Farmers are adaptable,” said Takle. “They adapt to pests and the markets, so the climate is just one more thing.”
With the ever-changing weather, staying on top of conservation could be a challenge.
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