Evolution can’t keep up with climate change

U. ARIZONA / YALE (US) — To adapt to the rapid climate change expected in the next 100 years, many vertebrate species would have to evolve about 10,000 times faster than they have in the past.

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. This is the first study to compare past rates of adaption to future rates of climate change.

“According to our data, almost all groups have at least some species that are potentially endangered, particularly tropical species,” says John J. Wiens. Above, the Mexican tree frog from the Yucatan Peninsula is one of many species whose existence is threatened by a warming climate. (Credit: John J. Wiens/U. Arizona)

The European Fire Salamander is one of several species of terrestrial vertebrates that could lose many of its populations but may be able to move to adjust its range to a changing climate. (Credit: John J. Wiens/U. Arizona)

The results, published online in the journal Ecology Letters, show that terrestrial vertebrate species appear to 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.

“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 J. Wiens, a professor in the department of ecology and evolutionary biology at the University of Arizona.

“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.”

Wiens conducted the research with Ignacio Quintero, a postgraduate research assistant at Yale University.

“We found that on average, species usually adapt to different climatic conditions at a rate of only by about one degree Celsius per million years,” Wiens explains.

“But if global temperatures are going to rise by about four 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.”

A degree or two

For their analysis, Quintero and Wiens studied phylogenies—essentially evolutionary family trees showing how species are related to each other—based on genetic data. These trees reveal how long ago species split from each other. The sampling covered 17 families representing the major living groups of terrestrial vertebrates, including frogs, salamanders, lizards, snakes, crocodilians, birds, and mammals.

They then combined these evolutionary trees with data on the climatic niche of each species to estimate how quickly climatic niches evolve among species, using climatic data such as annual mean temperature and annual precipitation as well as high and low extremes.

“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 explains.

“For most sister species, we found that they evolved to live in habitats with an average temperature difference of only about one or two degrees Celsius over the course of one to a few million years.”

“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,” he says.

“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.

Pick up and move?

He explains 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.”

In an earlier study, Wiens and co-authors asked what might actually cause species to go extinct. They showed that species extinctions and declines from climate change are more often due to changes in interactions with other species rather than inability to cope with changing conditions physiologically.

“What seemed to be a big driver in many species declines was reduced food availability,” Wiens says. “For example, bighorn sheep: If it gets drier and drier, the grass gets sparse and they starve to death.”

Source: University of Arizona

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  1. mememine

    “Scientific Consensus” means they agree it MIGHT not WILL be a crisis and it’s been 28 years!

    “Climate change is real and is happening and could cause unstoppable warming.” -Science

    NEVER have they said anything beyond “could” and “maybe” and “likely” and not one single scientific paper has ever said their crisis was as inevitable as they say comet hits are. A climate crisis “IS” a comet hit of an emergency so why won’t they give us a real warning for a real crisis? Because it’s not a crime to say a crisis might happen but 28 years of a “maybe” crisis proves 100% that it absolutely “won’t be” a real crisis.

    You doomers want this misery to be real so who’s the neocon again here?

    And get up to date:
    *Occupywallstreet now does not even mention CO2 in its list of demands because of the bank-funded and corporate run carbon trading stock markets ruled by politicians.
    *Canada killed Y2Kyoto with a freely elected climate change denying prime minister and nobody cared, especially the millions of scientists warning us of unstoppable warming (a comet hit).
    *Julian Assange is of course a climate change denier.
    *Obama had not mentioned the crisis in two State of the Unions addresses.

  2. Thomas

    “We found that on average, species usually adapt to different climatic conditions at a rate of only by about one degree Celsius per million years,” Wiens explains.

    Not arguing for or against the hypothisis of Global Warming, but here in Texas we get temperature variations of almost 90 degrees Fahrenheit in a year. Sometimes we get temperature swings of 40 degrees in a single day. By Wien’s statements everything in this part of the world should be dead or dying.

  3. Greg Bentall

    Global climate change is threatening many species. Coral reefs cannot tolerate the increased ocean temperatures. Coral reefs team with life of a multitude of species. But if you travel a hundred meters away from a coral reef in tropical seas you will find a lifeless desert. When the coral reefs die we lose essentially all living habitat in tropical seas.

    Polar bears will no longer be able to hunt seals from ice flows when there are no more ice flows. As the planet warms the warming process will accelerate, as methane gas, a super greenhouse gas is released from the oceans and tundra.

    It may already be too late to stop global warming. We have to wonder if human civilization will still be around in five hundred years.

  4. Thomas

    I am a “mature man” read that old guy. I have been diving on coral reefs in the Pacific and Caribbean for forty years. I have been to the Artic several times and a couple of years ago participated in a month long International expedition to Antarctica.

    I am amused by the people predicting doom & gloom and end of all life because of a minor change in temperature, or rainfall, or acidity. They have not experienced how tenacious life forms truly are on this planet and how you can’t keep flora and fauna out of an area no matter how hard you try. This is because Mother Nature never gives up and eventually she will win, although it may be long after you are dead and gone.

    Yes, some animals will have to move as habitats change or they will die. Some plants may not grow where they used to grow, or may grow where they never did before. That is the way nature works.

  5. Roberto

    Yes, some species will have to move or get extinct,
    some humans will have to move and some will dye… but nature is stronger and will survive.
    I agree with you. Why should be worry? The Universe will survive certainly!
    Ah ah ah!

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