Global Warming: Could Things Get Better Before They Get Worse?
April 13, 2012
Global warming could make things a little greener and a little rosier, according to new research. But these conditions may not last very long.
These new findings have been published in the journal Nature Climate Change this week. Within, evidence is shown that plants may experience a period of great growth and may initially thrive during global warming. Once this growth is over, however, plant life will begin to deteriorate quickly.
“We were really surprised by the pattern, where the initial boost in growth just went away,” said scientist Zhuoting Wu of Northern Arizona University (NAU), a lead author of the study.
“As ecosystems adjusted, the responses changed.”
To conduct this study, ecologists put four grassland ecosystems through simulated climate change for ten years. The ecologists noticed ...view middle of the document...
“These results show that we miss these surprises because we don’t study natural communities over the right time scales. For plant communities in Arizona, it took researchers 10 years to find that responses of native plant communities to warmer temperatures were the opposite of those predicted.”
To simulate the effects of global warming, the team of ecologists transplanted their four ecosystems from higher to lower elevations. The change in the temperature also brought about a change in rainfall, subjecting the subject ecosystems to periods of greater or lesser precipitation.
The ecologists studied grasslands typically found in Northern Arizona that can stretch from the San Francisco Peaks to the Great Basin Desert.
According to their results, periods of long-term warming resulted in a loss of native species as well as an increase of species usually found in warmer climates, pushing the native species out.
As these grasslands warmed, they cycled through their nitrogen more quickly. Going into the study, the ecologists believed this kind of action would take place and leave more nitrogen available for the rest of the community. What they didn’t expect, however, was how much nitrogen would be lost. As the nitrogen was cycled through, it quickly converted to nitrogen gas in the atmosphere or was washed out by rainfall.
Senior author of the paper and lead ecologist at NAU Bruce Hun gate said this loss of nitrogen is an important issue to note, as most researchers expect the increase of available nitrogen to sustain plant productivity.
“Faster nitrogen turnover stimulated nitrogen losses, likely reducing the effect of warming on plant growth,” Hungate said. “More generally, changes in species, changes in element cycles—these really make a difference. It’s classic systems ecology: the initial responses elicit knock-on effects, which here came back to bite the plants.”
“The long-term perspective is key,” said Hun gate. “We were surprised, and I’m guessing there are more such surprises in store.”