Gene Takle won part of a Nobel Prize for doing exactly what he’s doing now — sitting in his office on the third floor of Iowa State University’s Agronomy Hall and poring over computer models that will tell the land-locked millions in the Midwest what climate change will mean to them. 

He has some news. You know that saw about “it’s not the heat, it’s the humidity?” Well, there’s something to that, Takle said.

“Humidity is behind a lot of the things we are seeing,” he said. When it’s humid, people can’t perspire as much to cool themselves. Also, air-conditioning systems have to fight harder to cool rooms. Crops get stressed in the humidity.

Takle, director of ISU’s Climate Science Program, who joined ISU in December 1971, has been telling us for years that Iowa is in for higher temperatures, more frequent big rains, more runoff into streams, and a boost in crop production that eventually will turn around as the stresses of a whacked-out climate system bring drought, high heat and lower productivity. He is one of the most prominent modelers of regional effects of climate change. 

Remember that big climate report that The New York Times reported on earlier this month? It was part of the National Climate Assessment in which a group of leading scientists says the average temperature in the United States has risen sharply since 1980, with some of the warmest conditions in 1,500 years. The rise is largely due to human-related carbon emissions, the report notes.

The scientists made it clear that the effects of climate change already are being felt. Takle has been involved in high-profile modeling studies, including one that suggests that U.S. agricultural productivity could fall to pre-1980 levels by 2050, even with advances in drought-resistant seeds.

We interviewed Takle in his office about what this all means to business owners and other Iowans. Hint: You might want to plan on spending more on air conditioning. The Midwest is looking to see greater temperature increases than any other part of the country, Takle said. That will hurt agriculture while potentially boosting AC bills, a big deal when you are running 801 Grand or the Financial Center.

You have talked for years about higher temperatures and bigger rains coming as climate change continues in Iowa, but now humidity is going to be a problem, too.
What has been driving it is that weather stations across Iowa have all had increasing humidity over the last 47 years, especially in the April, May, June period. It’s been most notable in eastern Iowa. When we look at what is happening in the states to the east of us, they are seeing the same thing and even some are higher. It’s this bubble over the Midwest that is increasing, particularly in spring and early summer.
 
Spring and early summer are important around here. Some of us are trying to grow crops. Others are just trying to get outside after a long winter. Construction crews are busy. Are you saying those months are going to be particularly troublesome? 
We’ve been pointing to spring and early summer for a long time now. We’ve seen it in rainfall — rates are going up substantially in April, May and June since 2000. So we’ve seen, especially in northwest Iowa, it’s been noticeable. We did a study over the Cedar River basin as well. The (Iowa Department of Transportation) was wondering how to build bridges over the basin. So we did a study with 30-some models and projected out to 2050, and we found that the 100-year flood (1 in 100 chance each year) of the 20th century is now a 25-year flood of the 21st century (1 in 25 chance each year). This is a decision metric that is needed for designing a bridge over U.S. Highway 30 east of Cedar Rapids. 

So the bridge builders need to know the waters are rising at times. Farmers need to know we’ll have bigger rains, but bigger droughts, too. But there are ramifications for others, too, correct?
 
Oh, absolutely. The humidity ends up as rainfall, right? But humidity also is a key factor in the nighttime temperatures in the summertime, the warm season. A humid climate is going to have a muggy night. You go to Colorado and it’s 100 degrees during the day and it gets down to 79 at night. 

What effect does that have?
According to Jerry Hatfield (laboratory director of the National Laboratory for Agriculture and the Environment in Ames), it’s starting to be seen now in grain weight. So the scenario is this: The corn plant takes up carbon during the day, but it gives back a little bit of that carbon at night. The higher the nighttime temperature, the more it gives back. The best place to grow corn is in eastern Colorado; it’s nice and warm during the day and it cools off at night. But if the nighttime temperature is going up because it’s getting more humid, that means the respiration is going up, which means that during that grain-filling period in August, those nighttime temperatures are detrimental to the development of the seed and grain weight. So when you take it out of the field, a bushel might weigh 48 pounds instead of 52 pounds. They sell, of course, on weight, not volume. That is becoming worrisome. For the Midwest, when those temperatures start to go up, it’s going to impact yield and quality. 

Isn’t climate change supposed to boost yield at first, before a turnaround?
 
If you look at the evolutions of corn over the last 50 or 75 years, the growing season has gotten longer. Farmers have taken advantage of that. They plant earlier. They plant longer-season hybrids. They are getting better yields, so they are taking advantage of climate change. That’s a good thing. We have been getting good spring rains, so we have been getting good soil moisture recharge. We haven’t gone into the middle of June with a moisture deficit very much for years. 

In the ’80s and ’90s there was a yield increase because we haven’t been hitting any temperature issue. In fact, our summer temperatures, daytime maximum temperatures, have been going down. We have been avoiding temperatures over 100 degrees. It’s because we’ve been getting more rain, more humidity, more cloudiness. Not enough to harm photosynthesis, but enough to hold down that peak temperature. 

The National Climate Assessment is coming out in 2018. They looked at changes by midcentury and end of century in two emissions scenarios. The astounding thing is why the Midwest temperatures are projected to go up more than any other region. It’s because of the rainfall. We’ve gone through this sort of fantasy period where we’ve been getting a longer growing season; it’s warmer, we get more warming degree days and we have avoided those extreme heat events. What the projections seem to show is that world is going to come to an end. 

So are we coming up on some kind of tipping point?

Rain is much harder to predict with models, so the models are kind of all over the map. That’s partly just because Iowa sits on the gradient that’s dry to the west and wet to the east. That’s where we sit. If you look at the climate records, there is a big change across Iowa, (with yearly rainfall totals of) 28 inches in the west and 34 inches in the east. While the average rainfall is going up, the variability is going up also. We are getting more drought years and dry years and wet years.

So will average temperature and average rainfall continue to rise? 
Yes.

What are the effects of that on agriculture and other businesses? 
Corn doesn’t like temperatures much above 80. If it’s much above 84, you start to see yield drops. If we start getting a drier period with less cloudiness, it’s going to unmask this daytime heating and we could be going up more in the day and night. 

What about pests?
 
You could have more overwintering of pests. 

I got a call from a farmer in Algona in December. He said his electric bill had gone up dramatically. The co-op said it was because it was so humid. I told him we had dew points in the 70s last November. What is happening is you have this giant steel bin and you are driving air through it to dry it out. With 70s dew point, it’s just condensing right in the middle of the corn. The people over at (ISU’s department of) ag engineering think there is going to be some moldy corn coming out of the bin. 

This rise in humidity is kind of a subtle detriment in a number of ways. In the middle of summer it means more mold, more fungus, diseases on trees and shrubs. 

In 2013, we had over 700,000 acres that weren’t planted to anything because it was raining so much. 

We lose about 1.6 days of field work for every extra inch of rainfall. The number of workdays has been falling. 

Rolland Schnell, president of the Iowa Soybean Association, told (U.S.) Sen. Joni Ernst that he had to buy bigger equipment so he could plant his corn in a narrower window (due to rain). 

It’s a real factor. Farmers are paying for it. 

You drive across Iowa and you see this pattern of tile. It’s going in by the mile. 

Would the gentleman’s trouble with grain-drying translate to trouble with air conditioning in downtown Des Moines buildings? Is that an added cost?

Absolutely. Air conditioners were invented not to cool air but to take humidity out of the air. It takes a lot more energy to take the moisture out than to cool the air.