Evolution isn’t keeping up with climate change
A study has found that many vertebrates are evolving too slowly to keep up with the changes to the environment expected over the next 100 years due to climate change.
A study out of the University of Arizona has found that many species of vertebrates would have to evolve 10,000 times faster than they do in order to adapt properly to the changing climate. Scientists gathered data and analyzed how 540 species of vertebrates, including reptiles, birds, amphibians and mammals, have adapted to changing climate in the past. They compared their “rates of evolution” to the rates of climate change expected at the end of this century. The conclusion drawn by the study is that many species may face extinction if they can’t relocate or adapt to the climate.
“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,” explains John Wiens, professor at the University’s department of ecology and evolutionary biology, “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.”
Professor Wiens conducted the research project in collaboration with Yale post-doc Ignacio Quintero. “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,” continues Wiens, “but if global temperatures are going to rise by about 4 degrees over the next hundred years as predicted by the Intergovernmental Panel of 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.
Prof. Wiens believes the European fire salamander is one species that may be in jeopardy.
The research project involved looking at phylogenies, mappings of species in a family tree that shows how the species relate to one another. The map shows when species split from each other, and combined with data on the climactic niches for each species and how those changed over time, the team reached their conclusions.
“Basically, we figured out how much species changed in their climatic niche on a given branch, and if we know how old a species is, we can estimate how quickly the climatic niche changes over time,” Wiens says,”We then compared the rates of change over time in the past to projections for what climatic conditions are going to be like in 2100 and looked at how different these rates are. If the rates were similar, it would suggest there is a potential for species to evolve quickly enough to be able to survive, but in most cases, we found those rates to be different by about 10,000-fold or more.”
It must be stressed of course, that correlation doesn’t necessarily mean causation. Just because species evolves as a climate niche changes doesn’t mean the two are interlinked. Climate change is a difficult science, and there are more factors to consider than we usually take into account. Research like this often instills fears that we’re due for a mass extinction that will irreversibly damage the planet, but many people forget that Earth has been through this many times before. The medieval warm period between the tenth and 13th centuries for example, saw a dramatic rise in global temperatures. During these few centuries, Atlantic water temperatures are estimated to have been 1 C hotter than in the present. It was at this time the vikings explored the now ice-covered Greenland, and named it as such because of the lush green landscape they saw. Animals seem to have survived that period, so perhaps things aren’t quite so dire.