Scientists say annual weather proves little about climate trends, but this year and last, at opposite ends of the extreme weather spectrum, have strengthened Iowans’ belief that the state’s climate is changing.
“It’s always difficult to project long-term climate trends from short-term records,” but the last two years have been consistent with “the tendency over the past 30 years to more extreme weather,” said Iowa State University climate scientist Gene Takle.
While climate scientists regard recent weather as numbers in an expanding data set, the 2012 drought and this spring’s record rains have influenced Iowans’ perceptions of climate change, according to ISU sociologist J. Gordon Arbuckle Jr.
“Yes, I do believe recent extreme weather, with the whiplash effect from drought to floods, has gotten people’s attention,” said Arbuckle, who bases his assessment largely on the results of the 2011 and 2013 Iowa Farm and Rural Life Polls, in which researchers questioned Iowa farmers about their climate change beliefs..
The annual poll conducted by Iowa State University, shows that the percentage of farmers who believe that climate change is occurring increased from 67.7 percent in 2011 to 74.3 percent in 2013, while the percentage who believe it is not dropped from 4.5 percent in 2011 to 2.5 percent this year.
The questionnaire, which is sent to about 2,000 Iowa farms with half of them responding, also found that the percentage of farmers who think climate change is caused by human activity increased from 10 percent in 2011 to 17.3 percent this year.
“Those are pretty big jumps in two years,” said Arbuckle, who noted that the 2013 results are preliminary but not likely to change much when fully vetted.
The survey also found that the percentage of farmers who believe there is insufficient evidence to know whether the climate is changing fell from 27.8 percent in 2011 to 23.2 percent this year. The percentage who believe the climate is changing but attribute it to natural causes fell from 23.1 percent to 20.9 percent, and the percentage who believe climate change is driven equally by natural and human causes increased from 34.6 percent to 36.1 percent, according to the survey.
Arbuckle also participated in a larger survey of about 5,000 Corn Belt farmers that was administered in February 2012, before the erratic weather of the last two years. That survey found that 66 percent of farmers believed climate change is occurring while 31 percent were uncertain and 3.5 percent did not believe the climate is changing.
Officials discuss change
Activists encouraging Iowans to prepare for more extreme weather cite anecdotal evidence consistent with the poll’s findings.
“No question, people are getting more receptive to the message,” said State Sen. Rob Hogg, D-Cedar Rapids, the author of a recent book urging Americans to lead the world in slowing climate change and countering its ill effects.
As Hogg promotes his book, “America’s Climate Century,” he said he finds people responding positively to his call for action.
“The vast majority recognize that climate is changing. The role of greenhouse gas in those changes is not so widely accepted,” he said.
From Hogg’s perspective, the extreme weather of the last two years “adds to the evidence that weather is getting wackier, which is what scientists have predicted will happen.”
“Extreme weather is helping people connect the dots,” he said.
Rev. Susan Guy, executive director of Iowa Interfaith Power and Light, said recent extreme weather has provided her organization with opportunities to discuss climate change.
“People are starting to pay attention, to notice that, ‘Hey, this doesn’t seem normal,’ ” said Guy, whose faith-based organization advocates sustainable government policies and helps people and congregations reduce their carbon footprints.
When the organization was founded in 2006, climate change was more controversial, but attitudes are shifting, she said.
“Overall, people have been more open to talking about it,” she said.
Since 2008, when nine Iowa rivers reached record flood crests, “every year has been a vivid reminder of how extreme our weather can get,” said Takle, who in 1992 predicted most of the climate changes steadily becoming more apparent.
Among the most notable, Takle said in his Oct. 26, 2011, summary of Iowa climate changes, are substantial increases in annual precipitation, relative humidity, extreme rainfall events and the number of frost-free days .
Takle’s colleague, Daryl Herzmann, a scientist at ISU’s Iowa Environmental Mesonet, said the increase in intense rainfall events may well be the state’s strongest climate change signal.
That signal came in loud and clear this spring with downpours that washed away drought concerns and replaced them with flood worries in a matter of weeks.
The contrast between this year and last was especially pronounced in the March through July period.
That five-month period this year was the sixth-coolest and eighth wettest in 141 years of records, while the same period last year was the hottest and 20th driest, according to State Climatologist Harry Hillaker.
The only analogous period in state annals, he said, was 1901 (the third hottest and eighth driest March through July period) and 1902 (the third wettest and 10th coolest).