24th May 2017
Rapid greening of Antarctica due to climate change
Researchers have published evidence of a rapid greening in the Antarctic over the last 50 years. Mosses that once grew less than 1 mm a year are now found to be growing 3.2 mm a year on average, with up to a five-fold increase in overall mass accumulation.
Credit: Matt Amesbury
Plant life on Antarctica is growing rapidly due to climate change, scientists have found.
Few plants live on the continent, but scientists studying moss have found a sharp increase in biological activity in the last 50 years. A team including scientists from the University of Exeter used moss bank cores – which are well preserved in Antarctica's cold conditions – from an area spanning about 400 miles.
They tested five cores from three sites and found major biological changes had occurred over the past 50 years right across the Antarctic Peninsula.
Moss bank sites and meteorological records on the Antarctic Peninsula. Black dots are new locations in this study; grey dot is previously published; white dots are meteorological records, with decadal temperature trends.
"Temperature increases over roughly the past half century on the Antarctic Peninsula have had a dramatic effect on moss banks growing in the region," said Dr Matt Amesbury, of the University of Exeter. "If this continues, and with increasing amounts of ice-free land from continued glacier retreat, the Antarctic Peninsula will be a much greener place in the future."
Recent change on the Antarctic Peninsula has been well documented – such as higher temperatures, increased precipitation and stronger winds. Weather records mostly began in the 1950s, but biological records preserved in moss bank cores can offer a longer-term context about climate change. The scientists analysed data for the last 150 years, and found evidence of "changepoints" – points in time after which biological activity clearly increased – in the past half century. Mosses that once grew less than 1 mm a year now have growing rates of 3.2 mm a year, with up to a five-fold increase in overall mass accumulation.
"The sensitivity of moss growth to past temperature rises suggests that ecosystems will alter rapidly under future warming, leading to major changes in the biology and landscape of this iconic region," said Professor Dan Charman, who led the research project in Exeter. "In short, we could see Antarctic greening to parallel well-established observations in the Arctic.
"Although there was variability within our data, the consistency of what we found across different sites was striking," said Charman.
The research team, which included scientists from the University of Cambridge and British Antarctic Survey, say their data indicate that plants and soils will change substantially even with only modest further warming. The same group of researchers published a study focussing on one site in 2013, and the new research confirms that their earlier finding can be applied to a much larger region.
"This is another indicator that Antarctica is moving backwards in geologic time, which makes sense, considering atmospheric CO2 levels have already risen to levels that the planet hasn't seen since the Pliocene, three million years ago, when the Antarctic ice sheet was smaller, and sea levels were higher," said University of Massachusetts glaciologist Rob DeConto, who was not involved in the study, but reviewed it for the Washington Post.
"If greenhouse gas emissions continue unchecked, Antarctica will head even further back in geologic time. Perhaps the peninsula will even become forested again someday, like it was during the climates of the Cretaceous and Eocene, when the continent was ice free," DeConto added.
The paper appears in the journal Current Biology.
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