It's already happening: Hundreds of animals, plants locally extinct due to climate change
New study found local extinctions related to global warming have occurred in half of species studied
It may be tempting to take comfort in the idea that big changes related to climate change are decades away.
But a new study from the University of Arizona has found that local extinctions related to global warming have already occurred in almost half of the species studied.
The term "local extinction" is used when a species can no longer be found at a location where it once lived.
The study, authored by John Wiens, professor of ecology and evolutionary biology, was published Thursday in the journal PLOS Biology.
Wiens compared survey results of 976 species of plants and animals documented around the world 50 or 60 years ago to data on those same species gathered 10 years ago, he told CBC News.
He found that 47 per cent of those species — a representative sampling from around the world — were already locally extinct in the warmer parts of the regions where they were initially documented.
"The striking thing is that this has occurred with only less than a one degree [Celcius] increase in global medial temperature and it's going to get much worse," said Wiens. "There's going to be an additional one to five degrees on top of that."
He added that many people assume species loss from global warming is still a long way off. "They think, 'No, there's still a chance for this to not happen.' Basically my study shows there's been local extinctions in about half the species. This is all over the world, all kinds of different groups of organisms, all different habitats. So it's very wide spread."
Can't easily migrate
Only a small minority of animals can migrate to cooler, more hospitable ground, says Wiens.
"In some cases they do that, but in the organisms I study, they don't move around much as adults. Frogs, they hang around one pond their whole lives. Lizards hang around one rock pile."
A Canadian example
One species his study found to be locally extinct in parts of Canada is a bird called the red-breasted nuthatch, or Sitta canadensis, said Wiens.
Becky Stewart, a bird biologist with Bird Studies Canada, says her organization has observed climate change-related decline in bird populations.
The important thing is that it's not too late.- John Wiens, University of Arizona
"Impacts of climate change are particularly noticeable related to extreme weather events, which has impacts for some of the region's most at-risk bird species," said Stewart.
"For example, overly dry summers impact species whose key habitats include wet bottomlands. Impacts are seen in reduced nesting — swampy areas are dry and no longer suitable nesting habitat — and producing fewer young."
Holding out hope
Despite the urgency of the situation, Wiens told the CBC he still optimistic many of these species can be saved.
"The important thing is that it's not too late. The global extinctions haven't happened yet. These are all local extinctions," said Wiens. "If the trend continues, if it spreads to the entire range of these species, then yeah, they're gone and many more. But that hasn't happened yet.
"I like to think it's not too late to change."