Many vertebrate species (that category includes us) would have to evolve about 10,000 times faster than they have in the past to adapt to the rapid climate change expected in the next 100 years.
Scientists analyzed how quickly species adapted to different climates in the past, using data from 540 living species from all major groups of terrestrial vertebrates, including amphibians, reptiles, birds and mammals. They then compared their rates of evolution to rates of climate change projected for the end of this century.
The results show that terrestrial vertebrate species evolve too slowly to be able to adapt to the dramatically warmer climate expected by 2100. The researchers suggested that many species may face extinction if they are unable to move or acclimate.
Evolutionist John J. Wiens says, "Every species has a climatic niche which is the set of temperature and precipitation conditions in the area where it lives and where it can survive. For example, some species are found only in tropical areas, some only in cooler temperate areas, some live high in the mountains, and some live in the deserts."
"We found that on average, species usually adapt to different climatic conditions at a rate of only by about 1 degree Celsius per million years, but if global temperatures are going to rise by about 4 degrees over the next hundred years as predicted by the Intergovernmental Panel on Climate Change, that is where you get a huge difference in rates. What that suggests overall is that simply evolving to match these conditions may not be an option for many species."
"According to our data, almost all groups have at least some species that are potentially endangered, particularly tropical species."
Species can respond to climate change by acclimating without evolutionary change or by moving over space to track their preferred climate. For example, some species might be able to move to higher latitudes or higher elevation to remain in suitable conditions as the climate warms. In addition, many species could lose many populations due to climate change but might still be able to persist as a species if some of their populations survive. Barring any these options, extinction is the most likely outcome.
He explained that moving to more suitable climatic conditions may not always be an option for many species. "Some studies suggest many species won’t be able to move fast enough," he says. "Also, moving may require unimpeded access to habitats that have not been heavily disturbed by humans. Or consider a species living on the top of a mountain. If it gets too warm or dry up there, they can’t go anywhere. For example, bighorn sheep: If it gets drier and drier, the grass gets sparse and they starve to death"
The reasons that this is happening are complex. 2.8 million years ago, Earth began a cycle of alternating ice ages each lasting around a hundred thousand years, and interglacials lasting around 15,000 years. For this entire time, the number of species on the planet has been in decline, and now the rate of decline has reached climactic speed.
Typically the change between ice ages and interglacials is very violent. The last ice age ended in a matter of a thousand years and decimated species across the planet. This interglacial has now lasted roughly 15,000 years, and the stage is set for another climax, followed in time by a return to much colder conditions on Earth. This has not been caused entirely by human activity, but has been sped up by human emissions of carbon dioxide.
Whitley Strieber predicted the current situation in the Key, published in 2002. Only on Unknowncountry.com will you get truthful and accurate information about such important matters as climate change, presented without political bias. To keep news of this quality and importance coming, subscribe today.