Biodiversity Has Increased During Earth’s Warm Periods. But Climate Change Isn’t Off the Hook

A new study indicates that the number of species grew when global temperatures increased during periods in the geologic past. But that may not matter when it comes to rapid, man-made climate change.

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Alex Hare

It’s always nice to find people willing to challenge prevailing paradigms to seek truth. For some, that can mean doubling back on your own hard work. Take University of York biologist Peter Mayhew, who recently found that global warming might actually increase the number of species on the planet, contrary to a previous report that higher temperatures meant fewer life forms – a report that was his own.

In Mayhew’s initial 2008 study, low biodiversity among marine invertebrates appeared to coincide with warmer temperatures on Earth over the last 520 million years. But Mayhew and his colleagues decided to reexamine their hypothesis, this time using data that were “a fairer sample of the history of life.” With this new collection of material, they found a complete reversal of the relationship between species richness and temperature from what their previous paper argued: the number of different groups present in the fossil record was higher, rather than lower, during “greenhouse phases.”

“We’ve got a different story, really,” he said. “The net effect seems to be to improve biodiversity rather than reduce it.”

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Their previous findings rested on an assumption that fossil records can be taken at face value to represent biodiversity changes throughout history. This isn’t necessarily the case, because there are certain periods with higher-quality fossil samples, and some that are much more difficult to sample well. Aware of this bias, Mayhew’s team used data that standardized the number of fossils examined throughout history and accounted for other variables like sea level changes that might influence biodiversity in their new study to see if their old results would hold up.

Two years later, the results did not. But then why isn’t the Earth increasingly teeming with life as our temperatures get warmer? While the switch may prompt some to assert that climate change is not, in fact, detrimental to living creatures, Mayhew explained that the timescales in his team’s study are huge – over 500 million years – and therefore inappropriate for the shorter periods that we might look at as humans concerned about global warming. Many global warming concerns are focused on the next century, he said – and the lifetime of a species is typically one to 10 million years.

“I do worry that these findings will be used by the climate skeptic community to say ‘look climate warming is fine,’ he said. Not to mention the myriad other things we seem to do to create a storm of threats to biodiversity – think of what habitat destruction, overfishing, and pollution can do for a species’ viability. Those things, Mayhew explained, give the organisms a far greater challenge in coping with climate change than they would have had in the absence of humans.

“If we were to relax all these pressures on biodiversity and allow the world to recover over millions of years in a warmer climate, then my prediction is it would be an improvement in biodiversity,” he said. So it looks like we need to curb our reckless treatment of the planet first, if we want to eventually see a surge in the number of species on the planet as temperatures get warmer. We don’t have 500 million years to wait.

Tara Thean is a contributor at TIME. Find her on Twitter at @tarathean. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.

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A true scientist will admit an error when further research warrants it.  Mayhew should be applauded.


Facts to consider:

-Climate science has never said any crisis “will” happen, only “likely” etc. and their official stance is:

“Climate change is real and happening and could, maybe, possibly etc. lead to unstoppable warming”.

So how close to the brink of unstoppable warming do we have to get for the scientists to actually say it “WILL” happen. Help, my house is on fire maybe? Climate crisis would be like a comet hit.

-You can’t have a little crisis.

-Almost all climate change research is on “EFFECTS” not causes.

-Science gave us pesticides back when Rachel Carson considered scientists the enemy, not GODS.

-President Romney will thank you for condemning the voter’s children to the greenhouse gas ovens of climate change crisis. So is this exaggeration of crisis still worth it?

-Millions of people in the global scientific community don’t act like their kids are doomed as well.

*Obama has not mentioned the crisis in the last two State of the Unions addresses.

*Julian Assange is of course a climate change denier.

*Occupywallstreet does not even mention CO2 in its list of demands because of the bank-funded carbon trading stock markets run by corporations.

David S. Leaton
David S. Leaton

mememine is a troll.  "it" never engages in dialogue on comment streams.  A hit and run driver.

I'll respond anyway, as I do whenever I see mememine spreading misinformation.

Science does not provide absolutes.  Go to your priest if you want absolutes.  If scientists did speak using absolutes, we'd get complaints like "scientists shouldn't speak in absolutes!"  The IPCC, particularly in the recently released SREX (Managing the Risks of Extreme Events), defines the various levels of certainty:

Define "little" mememine.

Almost all climate change research is not on effects.  Look at the reference sections of the IPCC's Working Group 1 report from AR4.   It's easy to make these claims when you know you're not going to stick around to provide evidence.

Grant Harmon
Grant Harmon

The inanity of this comment is overwhelming


Just goes to show that there are lies, d@mn lies, and statistics. Who knows, in 4 years maybe this very same researcher will determine that warmer temps bring no more or less biodiversity. 

Grant Harmon
Grant Harmon

You sir, obviously have a firm grasp on how scientific research is conducted and interpreted.  I applaud you.