“I’ve experienced weird weather personally,” reported Hans Schmitz, showing a slide depicting his Posey County family farm’s destruction after a tornado.
“Weather is the day-to-day variations in the earth’s atmosphere measured at a single moment in time. Climate, meanwhile, is by definition ... the average of a weather variable.” Climate change is the difference between a weather variable during that initial 30 years and a different 30 years. To confuse matters, the 30-year periods can overlap.
When the 1971-2000 averages came out, it took 18 months for them to be checked. The 1981-2010 averages were referred to as the new normals. The agricultural meteorologist said, “The differences between those two sets of 30 years were so different it took extra long to quality check them.” He predicted when the 1991-2020 numbers arrive, “We’re going to have substantially different numbers again.”
Indiana has nine climate divisions. Southeastern Indiana, both Ripley and Franklin counties, are “right on the line in climate division 9. ... Just to the north is a different climate division.” North of Interstate 70 is defined as a snow climate. South of I-70 is a fully humid summer climate. “The difference in humidity down here compared to northern Indiana is significant ... and we don’t expect snow to stick around more than a week.”
Showing a chart, the speaker said, “You see over time there’s been a slight trend in increasing minimum temperatures in the summer. When I started in Purdue Extension, you could always define (weather) ... by how the tomatoes were doing.” During the last four years, citizens tell him, “‘My tomatoes start to set fruit, then all of a sudden they rot on the vine or just stop for about two to four weeks.’ That’s when I’ll get the call.” He tells them to wait for temperatures to start decreasing a little bit and it will be fine. “When you get above 86 degrees, tomatoes stop growing. They go dormant.”
The Purdue Extension Posey County agriculture and natural resources educator gave an example of what future climate could be like in Jefferson County just south of Ripley. Now 21 nights on average have lows above 68 degrees. By the 2050s, nights above 68 degrees could range from 53 to 65 “if we do nothing at all.” If area residents take measures to reduce climate change, the number of nights could be lower.
“Global warming is a hard sell in Indiana because Indiana does not experience global warming. ... In Indiana, particularly southern Indiana, maximum temperatures on average aren’t really increasing.” But the number of hot days could. In the past, the average number of days above 90 degrees was 27. “By the 2050s, expect that to double” between May and September.
Precipitation is increasing about two-thirds of an inch per decade, “not a whole lot until you look at how it falls.”
The number of days with 1.25 inches of precipitation or more rises from 40 to 46, so intense storms will be more frequent. There will be more runoff and flooding in the summer and fall, yet an increase in drought conditions.
Frost-free growing days are April 20-Oct. 21 now. That number could grow by 30 days between 2040-70 — to April 4-Nov. 4.
Different types of plants may be able to thrive here in the future. Schmitz explained, “Perennials are the sole reason we have plant hardiness zones,” which follow weather zones. Southeastern Indiana is between zones 5-6, which is defined by the coldest temperature over 30 years. In northern Indiana, the coldest winter night is -20 to -10 degrees, while here it’s -10 to 0 degrees.
“We would expect to transition to zone 7.” The minimum temperature here would then be 0 to 5 degrees.
The presenter listed many impacts of climate trends: pests (weeds, insects, crop disease), heat stresses, greater fertilizer need, growing season timing changes, increased need for water absorption. “We need to find a way to get our soils able to withstand both conditions,” too much rain and not enough.
There are three different kinds of photosynthesis (the way plants convert carbon dioxide to carbohydrates):
• C3 — cool season, 85% of the globe’s plants, including soybean, tomato, pumpkin, watermelon, cucumber, wheat. At 32 degrees a C3 crop will be able to photosynthesize. At 86 degrees C3 crops stop photosynthesizing.
• C4 — warm season, 10% of the globe’s plants; corn, sorghum and sugar cane, “very important crops.” At 50 degrees a C4 crop will begin to photosynthesize.
• CAM (crassulacean acid metabolism)
“At 110 degrees there’s no longer any way to control the amount of water that plant needs” to deal with high heat. “If temps are rising, C4 plants have a little bit of an advantage going forward.”
One research finding is interesting. The leaf tissue of wheat exhibits C3 growth, but when that wheat plant starts to get ready for harvest, it has some enzymes that approximate C4 growth, which means the plant can switch photosynthetic pathways. Schmitz pointed out, “We’ve got real potential to start adapting for what we’re going to experience in the future.”
Climate change presents other opportunities:
• double cropping or intercropping to take advantage of the longer growing season
• cover cropping that boosts soil organic matter will increase water absorption and holding capacity
• application of nutrients at the right time. He advised fall application of anhydrous or nitrogen will have to stop.
Schmitz then looked back in ag history. An overreliance on certain crops and livestock has been catastrophic when pests showed up. The Irish Potato Famine happened when a fungus-like organism spread rapidly throughout Ireland, ruining half the crop and more in following years. Corn was decimated by the Southern corn leaf blight, a fungus, in 1970. African swine fever has killed about half of China’s hogs today. Emerald ash borer has wiped out 90% of those trees.
The chair of the North Central Climate Collaborative, a 12-state team of extension professionals, pointed out, “If we’re growing one crop and a pest comes in, we get wiped out.” If growing five or six, “we’ve still got something at the end of the year.”
“When corn and soybeans were not profitable, dairy was profitable” and vice versa. “Diversification helped offset the industry.”
He concluded, “Climate is changing in observable ways. Some confidence can be placed in future trends. We can predict a little bit and hedge against risk.” He recommended diversification as an economic solution for changing climate.