Species extinctions happening before our eyes

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"Species extinctions happening before our eyes"


This post was originally published in Skeptical Science.

In the past, research has predicted that global warming could lead to the extinction of more than one-fifth of animal and plant species. This research has largely been based on theoretical models. However, now observations can confirm whether reality matches theory. The paper Erosion of Lizard Diversity by Climate Change and Altered Thermal Niches (Sinervo 2010) compares global observations of lizard populations from 1975 to present day. The result? Rapidly warming temperatures are causing lizard species to go extinct before our eyes.

How does climate change affect lizard populations? While lizards bask in the morning sun to warm up, they retreat to the shade when temperatures get too hot to avoid heat stress. As it gets hotter, they have less time to forage for food. Warmer springs are particularly devastating as this is when lizards reproduce and need extra food.
Sinervo 2010 first analysed observations of lizard populations in Mexico. Since 1975 when observations began, 12% of local populations have gone extinct. Looking at weather station data, they found a correlation between the change in maximum temperature and local extinctions. The number of hours that lizards were forced to retreat to shade were significantly higher at extinction sites.

There are two ways species can compensate for climate change: adapt or migrate. Temperatures are changing too rapidly for most species to evolve in order to adapt to warmer temperatures. That leaves migration. What is being observed is species are relocating to cooler regions in response to warming temperatures. Lizard populations from lower elevations are expanding up to cooler, higher habitats. This appears to be exacerbating extinction of species already living in higher elevations.

Another important result they found is if we manage to reduce CO2 emissions over the next few decades, this will reduce the number of species extinctions in 2080 but have little effect on the extinctions by 2050. A slow down in global warming will lag atmospheric CO2 levels by decades. This lead the authors to conclude that lizards have already crossed a threshold for extinctions.

JR:  Here is the abstract for the Science paper:

It is predicted that climate change will cause species extinctions and distributional shifts in coming decades, but data to validate these predictions are relatively scarce. Here, we compare recent and historical surveys for 48 Mexican lizard species at 200 sites. Since 1975, 12% of local populations have gone extinct. We verified physiological models of extinction risk with observed local extinctions and extended projections worldwide. Since 1975, we estimate that 4% of local populations have gone extinct worldwide, but by 2080 local extinctions are projected to reach 39% worldwide, and species extinctions may reach 20%. Global extinction projections were validated with local extinctions observed from 1975 to 2009 for regional biotas on four other continents, suggesting that lizards have already crossed a threshold for extinctions caused by climate change.

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24 Responses to Species extinctions happening before our eyes

  1. duane Smith says:

    Don’t you all believe in Darwinism? Species will all adapt and new species will develop. No problemo.

  2. catman306 says:

    duane Smith, you are correct. But the adaptations begin when the climate stabilizes again, be it with the climate we grew up with or something else entirely. It is stable climate that allows for niche filling adaptations with extensive speciation n. Unstable climate just causes extinctions.

    We’ll have a different climate, without doubt. What we need is a stable climate.

  3. Rabid Doomsayer says:

    Duane,
    Cyanobacteria will be happy. Oxygen phobic bacteria will be the only winners.

  4. homunq says:

    No problemo for earth; it’s seen worse. For extinct lizards, it’s a brief problemo and then nothing. For humans? Houston, we have a problemo.

  5. Tim L. says:

    Then again, we’ve seen a proliferation of other types of lizards: the Koch brothers, George Will, Patrick Michaels, and all the rest of those climate disinformationists who’ve whored themselves for the oil industry.

  6. Mike#22 says:

    Time to cool the planet.

  7. glen says:

    “Then again, we’ve seen a proliferation of other types of lizards: . . .”

    like the pitchgecko with an accent that works for a major insurance company.

  8. villabolo says:

    duane Smith says:
    August 21, 2010 at 6:35 pm

    “Don’t you all believe in Darwinism? Species will all adapt and new species will develop. No problemo.”
    * * * * * * * * * * * * * * *
    Have you considered sterilizing your children and or grandchildren?

  9. Karen S. says:

    I read statements like Duane’s and I cringe. It’s the usual tiresome response from the uninformed, who just don’t get it about the utterly connected dependence between living ecosystems and their own precious human selves. As long as grocery store shelves are full and gas is cheap enough and the Wal-Mart still offers blue light specials, why should Duane care? Maybe he might like to try evolving–it’s easy, right? Let’s see…

    Say Duane is a hummingbird, for argument’s sake. He’s just flown the over-water portion of his annual migration, 600 miles across the Gulf of Mexico from Central America to the coast of Mississippi. Mortality is high; nearly half his compadres have died enroute. (Mortality for migrating birds can be 50%). Duane flew all the way on two ounces of fat which he gained before leaving his wintering habitat in the jungle. Now he’s tired and famished, his reserves almost gone. He makes it to the beach; there’s a tree. He lands, finding very little space on a branch already occupied by twenty other birds of different species. Every branch is full. Each tree has hundreds of exhausted birds in it. Duane rests, then goes in search of food. But the food’s been wiped out. Pick a reason, there are plenty in the Gulf right now. What does Duane do now? Evolve? Go to Safeway? Not quite. For birds, fish, mammals, etc, it’s a direct consequence. No food, you die.

    We don’t eat hummingbirds but just like any species we do need clean air, clean water, safe food, and shelter or we die. I won’t go into the fragility of our food supply chain–there are lots of examples in the Third World, of disruption and consequence. But hubris such as that exhibited by Duane and many more of the comfortable, who don’t understand the connections between themselves and the natural world, is dangerous. Left untreated, hubris on a large scale will prove fatal.

    I worked with endangered and threatened species for 15 years while in the US Fish and Wildlife Service (I’m retired now), and saw firsthand the process, the politics, and the carefully and painstakingly compiled scientific evidence that built the case for listing each species. BTW, the number of plants and animals who’ve made it through the process is the tip of a very big iceberg, no pun intended.

    A few points for perspective: The USFWS annual nationwide budget for listing species was less than the District of Columbia’s citizens spent on Domino’s pizza each year, or, put another way, less than the cost of one mile of highway. The average percentage of endangered and threatened species that depend on wetlands for all or a significant part of their lives (across all groupings of species including plants) is a minimum of 50 percent. The areas identified by a group of biologists including myself in the mid 1990s as future hot spots for wetlands loss due to development (we hadn’t factored in climate change back then) and therefore hot spots for species in trouble was: the Gulf coast states, namely Mississippi, Alabama and their neighbors. A one acre wetland can hold more than 300,000 gallons of water (more than a good-sized tanker) when flooded to a depth of one foot. A quart of oil can cover an area of water the size of a football field. It can take several years to list a species. The Bush Administration listed the fewest number of species by an order of magnitude, of any administration since the Endangered Species Act was passed in 1973. The backlog of species is huge. The ESA is legislative triage for the worst emergency room cases.

    You add up climate change, our unrelenting addiction to oil that brings us catastrophes like the Gulf, attitudes that persist like Duane’s, and the already shrinking amount of habitat from development, and you have not just a perfect storm but a gigantic extinction event. We are in the middle of something that hasn’t been seen since the middle of the Cretaceous, more than 65 million years ago.

    Thought a little perspective would be useful here.

  10. Colorado Bob says:

    Please find a real lizard .

    ( PS I hate whiners and after the fact editors , but find a real lizard. )

    [JR: Irony, anyone?]

  11. Colorado Bob says:

    Paulm @ 1

    Looks like the “Black Saturday” vote holds the keys to power.

  12. Jim Eaton says:

    Karen S. above explained the problem extremely well. I spent my career working to designate California’s wildlands as legally protected wilderness areas, but I now am facing the fact that all I did may ultimately be for naught. Kinda if sobering.

    Life will go on, as it did after the K-T extinction event. But it will be a shame to lose all the wonderful, diverse, beautiful, and amazing life forms that evolved over the last 65 million years. Disturbingly, the choice of preserving our existing amazing biodiversity is in the hands of humans today, but we appear to be voting in favor of wiping the slate clean (including ourselves) and starting over. What a pity!

  13. Colorado Bob says:

    Adam Bandt took the seat of Melbourne from Labor.

    Melbourne is where the fruit bats were dropping from the trees dead on the Friday before ” Black Saturday ” . It was 114 F that Friday in Melbourne.

  14. Scott says:

    #11. Colorado Bob,

    I saw a small lizard in the yard today. Now what?

  15. Colorado Bob says:

    ” I now am facing the fact that all I did may ultimately be for naught. ”

    Jim –
    You don’t know that for sure, you may prove to be the bridge that some small creature needed .

  16. Colorado Bob says:

    Scott –
    I was referring to a using a corporate logo of a cartoon gecko, on a post about real lizards going extinct.

  17. Anonymous says:

    Let’s not forget about new winter phenomenon

    Cold weather kills off Florida wildlife
    Iguanas, pythons and other non-native species are freezing to death as temperatures plummet in the Sunshine State http://www.guardian.co.uk/environment/2010/feb/15/cold-weather-kills-florida-wildlife

  18. dhogaza says:

    Jim Eaton

    Karen S. above explained the problem extremely well. I spent my career working to designate California’s wildlands as legally protected wilderness areas, but I now am facing the fact that all I did may ultimately be for naught. Kinda if sobering.

    Yeah, I’ve spent a lot of time involved in conservation work (15 years on the board of one of Oregon’s largest conservation non-profits), and feel the same. As you know, we’re not alone in this feeling, the Nature Conservancy has been studying the possible effects of global warming on the effectiveness of their botanical reserves strategy for some years now.

  19. Paulm says:

    We’ve gone into the ecological red
    On 21 August our environmental resource budget ran out. Now we’re living beyond the planet’s means to support us

    http://www.guardian.co.uk/commentisfree/cif-green/2010/aug/22/global-resources-deficit-land-water-oil

  20. Jim Bouldin says:

    Be careful on the interpretation of these kinds of reports folks. Don’t jump. Read the papers themselves carefully first.

  21. Wit'sEnd says:

    Karen S., well said. Jim Bouldin, you don’t need to read any papers to see that the ecosystem is collapsing, unless maybe you live in a city and never walk through a park or get out to the country – or even the suburban areas where homes have yards with trees. Plants are dying, and they are the base of the food chain. They are dying because the atmosphere is toxic, just as life in the sea is dying because the water is toxic.

  22. Jim Bouldin says:

    Wit’s End… ah nevermind.

  23. Wit'sEnd says:

    Oh, I don’t mind Jim Bouldin. Maybe when you’ve got family members living in this sort of hell, (where the first victims of societal breakdown are women like my daughters – and yours, if you have any) http://www.huffingtonpost.com/2010/08/23/some-200-women-gangraped-_n_690960.html, a movie coming soon to a theatre near us, you will pull your scientific head out of your scientific butt, and dghoza will stop banging his scientific head on his scientific desk, and you will think for a brief moment, maybe she had a point…