Scientists have found that climate change has lengthened the life span of birds by about 20%, reducing their life span and increasing their overall mortality rate
As the global climate continues to heat up, it is the plants that will eventually have to give way. But it is also the animals that could face an extra upheaval: an extra fattening up.
Scientists have found that climate change has shortened the life span of birds, by about 20%. It will reduce their life span by an average of a year, and will lead to an average mortality rate of 0.2% over their entire lifespan.
For humans, the results are more dramatic. Cataclysmic climate change will cut the average lifespan by more than five years, with an average mortality rate of 12.2%, according to the report from the Natural Environment Research Council (Nerc) in the journal Proceedings of the National Academy of Sciences.
“If climate change makes people less fertile, then natural selection will make people more robust,” the researchers said.
The data on avian life span came from a database of more than 15,000 birds which have died around the world over the past hundred years.
The mean age of birds in the database is now about 17 years, which means that more and more birds are ageing faster and faster, even though there are fewer birds than 100 years ago. The natural average of avian life span is about 13.7 years.
“The ongoing decline in avian life spans is an alarming consequence of climate change,” the authors concluded. “It raises the prospect of ongoing impoverishment of humanity because fewer bird species will be available to feed human societies.”
Death rates among bird species have been increasing for the past 50 years, with species across the board showing a greater tendency to die in old age.
Some of the world’s most vulnerable bird species, such as the Greater Spotted Heron, Slow Tern and Bewick’s New Millennium, have been particularly hard hit.
The scientists said that climate change is expected to have a significant impact on bird species. But when they considered the adaptation rate that animal species could make to climate change, which is about 100 times slower than climate change itself, “chronic evolutionary decline is likely to be unavoidable for many species”.