Plants, including many that, as crops, feed the world, may run out of time to grow if climate change continues to warm up the planet, a new study suggests.
Although some have suggested plants would actually benefit from the warmer temperatures and elevated levels of carbon dioxide climate change could bring, those exact same conditions could bring disaster in other parts of the world, the study authors warn.
In the Northern Hemisphere, where climate warming benefits have been suggested, plant and crop growth there will still be limited by the amount of solar radiation they receive — scarcer the farther north you go because of the shape of the earth — and that will not change, they point out.
Meanwhile, many plants growing in tropical regions will find the increased heat impossible to deal with, especially if warming also brings drought, they suggest in a study published in PLOS Biology.
The researchers analyzed satellite-derived data to determine the temperature ranges, amount of sunlight and water availability in which 95 percent of the globe's plant growth currently takes place.
"Those who think climate change will benefit plants need to see the light, literally and figuratively," says study lead author Camilo Mora, an ecologist and professor of geography at the University of Hawaii at Manoa.
"A narrow focus on the factors that influence plant growth has led to major underestimations of the potential impacts of climate change on plants, not only at higher latitudes but more severely in the tropics, exposing the world to dire consequences," he says.
Continued climate change is likely to result in overall declines in plant growing seasons by 2100 due to a mixture of warming and drought, coupled with the inescapable factor of limited solar radiation, the researchers say.
Some tropical regions could see a reduction in growing days of as many as 200 per year by the end of the century, and overall, the entire Earth could experience an approximate 11 percent decrease in days with climate suitable for plant growth, they predict.
In the tropics especially, the impact would be hard on as many as 2.1 billion people living in countries heavily dependent on plants and agricultural crops for their food, jobs and economic well-being.
"Climate change will have disproportional impacts on the poorest in the world," says study co-author Micah Fisher.
One bright spot in the study, the researchers say, is the finding that achieving even modest goals of emission reductions could prevent the most drastic changes, improving the outlook for ecosystems and the people who depend on them.
