Global Warming is Causing Earlier Springs and Later Autumns in Forests

Climate change is causing temperatures to warm all along the east coast and now, these higher temperatures are causing spring to come earlier than ever. Scientists have found that over the last two decades, forests throughout the Eastern U.S. have experienced earlier springs and later autumns than ever before.

In order to find out how forests have changed over the past several years, the scientists integrated observations from three sources-satellite imagery, ground observations, and instrument towers. This allowed them to capture both a region-wide picture of the eastern forest as well as more granular measurements from individual states. They tracked when forests across the region began to turn green in the spring and then when the leaves began to turn in the fall.

"What we find in this paper is an increase in the growing season of forests in the eastern U.S. due to recent climate change," said Trevor Keenan, one of the researchers, in a news release. "This has been beneficial for forests in the past, but we do not expect the response to continue unchecked in the future. It must also be kept in mind that this positive effect of warming is but one amid a barrage of detrimental impacts of climate change on the Earth's ecosystem."

Essentially, the researchers found that spring is arriving earlier, the growing season is lasting longer, and autumn is occurring later. Yet they also found that there's a significant source of error in existing computer models of how forest ecosystems work. It turns out that these models don't properly reflect how spring and autumn temperatures control the start and end of the growing season.

"What that means if you run these models forward 100 years, they won't be accurate," said Andrew Richardson, one of the researchers, in a news release. "This shows an opportunity to improve the models and how they simulate how forests will work under future climate scenarios."

The findings reveal a bit more about how climate change is impacting the seasons in a visible way. In addition, the research could help develop better computer models for the future.

The findings are published in the journal Nature Climate Change.