It’s not the Heat…Well, Yeah, maybe it is the Heat
October 27, 2011
We’ve heard it a hundred times – “More CO2 is good for plants.”
Agronomists and Botanists around the world have been asking food crops the question – “So how is all the extra CO2 working out for you?”
For years, as scientists have assembled data on climate change and pointed with concern at melting glaciers and other visible changes in the life-giving water cycle, the impact on seasonal rains and irrigation has worried crop watchers most.
What would breadbaskets like the U.S. Midwest, the Central Asian steppes, the north China Plain or Argentine and Brazilian crop lands be like without normal rains or water tables?
Those were seen as longer-term issues of climate change.
But scientists now wonder if a more immediate issue is an unusual rise in day-time and, especially, night-time summer temperatures being seen in crop belts around the world.
Interviews with crop researchers at American universities paint the same picture: high temperatures have already shrunken output of many crops and vegetables.
“We don’t grow tomatoes in the deep South in the summer. Pollination fails,” said Ken Boote, a crop scientist with the University of Florida.
The same goes for snap beans which can no longer be grown in Florida during the summer, he added.
“Its impact on agriculture systems, impacts on crops, mitigation strategies with soil management — a whole range of questions was being asked about climate change,” said Jerry Hatfield, Laboratory Director at the National Soil Tilth Laboratory in Ames, Iowa.
“The biggest thing is high night-time temperatures have a negative impact on yield,” Hatfield added, noting that the heat affects evaporation and the life process of the crops.
“One of the consequences of rising temperatures … is to compress the life cycle of that plant. The other key consequence is that when the atmosphere gets warmer the atmospheric demand for water increases,” Hatfield said.
“These are simple things that can occur and have tremendous consequences on our ability to produce a stable supply of food or feed or fiber,” he said.
see Dr. Hatfield’s 2009 testimony to congress below, and my own video on the “CO2 is Plant Food” crock: