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From Nature magazine
Rather than kicking off the expected cycles of extinction, periods of warming in Earth's history were accompanied by increased biodiversity, according to a report published this week. But this does not mean that the mass extinctions that are taking place today, with Earth warming at an unprecedented rate, will be reversed in future.
Researchers examined the number of known families of marine invertebrates, as well as sea-surface temperatures, over the course of 540 million years of Earth's history1. They found that when temperatures were high, so was biodiversity. When temperatures fell, biodiversity also declined.
The results contradict previous work, including findings from lead author Peter Mayhew's group2, that reported an inverse correlation between high temperatures and biodiversity.
The reason for the about-face, says Mayhew, an evolutionary ecologist at the University of York, UK, is that the earlier work measured fossil diversity by tallying the first and last appearances of each group of species, then assuming that the creatures existed only during the intervening years. This might sound logical, but overlooks the fact that some geological periods are better studied than others.
To correct this, the new study looked only at the well-sampled periods. And, instead of interpolating organisms' presence from origination and extinction dates, it merely tallied species groups present during each period.
Even so, given that climate change is generally viewed as disruptive, Mayhew admits it was a "big surprise" to find that eras of warming were accompanied by increases in biodiversity. The work also provided a solution to another puzzle, Mayhew says. Tropical ecosystems are known to be Earth's most diverse, and the tropics would be expected to expand during warm eras. Yet in the past these eras were thought to be species-poor compared with cooler ones. The new results resolve that contradiction.
Speed kills
Warming produces both extinctions and originations, and in the past the originations of new species have outstripped the loss of old ones, says Mayhew. But this does not mean that today's climate change will be beneficial.
"The rate of change is very important," Mayhew says. For diversity to rise, he explains, new species need to evolve. And that takes between thousands and millions of years — much slower than the rate at which extinctions are likely to occur with today's rapid change.
Scott Wing, a palaeobiologist at the Smithsonian Institution in Washington DC, agrees. "This article has nothing to say about the effects of global warming at any timescale of interest to most humans," he says. But he adds, "this is definitely of interest to evolutionary biologists, palaeontologists and ecologists seeking to understand very broad patterns of diversity".
However, Shanan Peters, a palaeobiologist at the University of Wisconsin-Madison, isn't so sure the paper is noteworthy. Its primary result, he points out, is to overturn Mayhew's own prior finding and bring the long-term diversity results into line with ecological common sense. "Palaeobiologists and climatologists have long referred to warm intervals as 'climate optima'," he notes, "precisely because it is during such times that palm trees and alligators inhabit the Arctic and life appears to be diverse and flourishing."
More interesting, he says, will be the next generation of results, when palaeobiologists turn their attention to major climate transitions, such as that which may be occurring now.
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13 Comments
Add CommentBad news for the short term, good news for the long term? Opinions?
Reply | Report Abuse | Link to thisThis will not get much coverage unfortunately.
Reply | Report Abuse | Link to thisGood news for the long term? Nope, not this time. Previous cycles there were no modern humans to get in the way of diversification.
Reply | Report Abuse | Link to thisThis seems kind of obvious. It looks more like coming up with an excuse for an article to keep adding to the claim that somehow today because of us evil humans it is all different. I guess there were too many articles recently with evidence that global warming is natural, so this one was created to get a warmist vision back in, basically somehow now is different and wont be reversible in the future plus somehow even though biodiversity increases with warming every other time and future warming will somehow be mass extinctions.
Reply | Report Abuse | Link to thisWhy don't we all just agree that nobody is entirely sure what is going to happen in the future.
Reply | Report Abuse | Link to thisSo what happened to the warmists who claim exactly the opposite. Where o where did their catastrophe go??
Reply | Report Abuse | Link to thisPerhaps this will help reduce the amount of rhetoric being spewed. When actual data is examined the CAGW meme and the blaring klaxons are seen for what they are.
No actions should be contemplated until all data is in. Otherwise we may hurt ourselves. GK
I'm pretty sure biodiversity ranks pretty low on anyone's list of global warming concerns. More important are the unbearable heat, epic droughts, 100 year floods becoming 10 year floods, and sea level rise, to name a few. The data IS in on those things, and it shows that we need to act now.
Reply | Report Abuse | Link to thisIt is NOT in. There is NO evidence of increased extreme weather events, only the spin & manipulated data promotes this lie.
Reply | Report Abuse | Link to this"More important are the unbearable heat, epic droughts, 100 year floods becoming 10 year floods, and sea level rise, to name a few. The data IS in on those things, and it shows that we need to act now."
Reply | Report Abuse | Link to thisIf only there was some evidence of this outside your precious models.
Here is a paper, just published, which indicates this warm cycle is nothing unusual, nor the declining ice:
“Recent Antarctic Peninsula warming relative to Holocene climate and ice-shelf history” and authored by Robert Mulvaney and colleagues of the British Antarctic Survey (Nature, 2012, doi:10.1038/nature11391), reports two recent natural warming cycles, one around 1500 AD and another around 400 AD, measured from isotope (deuterium) concentrations in ice cores bored adjacent to recent breaks in the ice shelf in northeast Antarctica. GK
GK - Love reading your intelligent, informed comments. Thanks for giving balance to otherwise very biased responses.
Reply | Report Abuse | Link to thisCarlyle - The beer is still cold.LOL!
Problem with your logic: both wraming events are less than we've already gone, and are much slower. As I've told Your Obstinacy before, it's the speed of the change, not the amount.
Reply | Report Abuse | Link to thisYou think that the guy who thinks that 800ppm of atmospheric CO2 is a good thing is intelligent? You worry me sometimes. I have told you before, and will tell you again, check the PETM.
Reply | Report Abuse | Link to thisFurthermore, the last time that CO2 went above 800ppm was the Smithian stage of the Triassic period, when the Earth's equatorial zones were literally too hot for animal life and ocean surface temperatures broke 40 degrees Celsius.
"""It is NOT in. There is NO evidence of increased extreme weather events, only the spin & manipulated data promotes this lie."""
Reply | Report Abuse | Link to thisLIE. Have you seen the droughts sweeping much of the world, and the floods sweeping most of the rest? Just as an example, in my area (East coast), last year was the wettest on record. At my grandparents' house just across the Appalachians, it was one of the dryest.