Our Earth is a grassy place, under it all. And that's important.
Grasslands are the highest portion of our planet's land area, giving balance and absorbing carbon and providing agricultural crops. They occupy 52.5 million square kilometers, or 40.5 percent of the terrestrial area that excludes Greenland and Antarctica, according to 2000 numbers from the World Resources Institute.
It turns out that toward the end of this century, grasslands North America-wide will have rising summer temperatures and drought. A new study, led by researchers at Harvard University, has worked out a model showing what is likely to happen on grasslands in this country and in Canada and Mexico in reaction to climate change.
For one thing, they say that an earlier spring growing season and higher winter temperatures will likely offset and even out vegetation growth. Their model was published recently in the journal Nature Climate Change.
"This research brings new insights into predicting future climate-driven changes in grasslands," Elizabeth Blood at the National Science Foundation's Division of Environmental Biology, said. The NSF funded the study. "The results show that annual grassland cover and productivity will increase despite drought-induced reductions in summer productivity and cover."
In the projected changes, the growing season would become two parts, co-author Koen Hufkens said. "You have an earlier spring flush of vegetation, followed by a summer depression where the vegetation withers, then at the end of the season, you see the vegetation rebound again."
While it's true that the grassland productivity would not decline for most of the region, the split seasons would not be covered by current practices for management of grassland and agriculture, co-author Andrew Richardson said.
In the study, the team looked at the entire region's vegetation and water systems, sourcing 250 cameras that monitor local conditions in vegetation every half hour. While measuring levels of greenness in those areas, they were able to project into the future as well.
For sure, there will be a need to make adjustments: "It's getting more arid and that's causing more intense summer droughts, but because of a changing seasonality, vegetation growth is shifting," Richardson said.
While adjustments can be made, Richardson noted: "But that raises new questions about appropriate management responses."
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