‘Nowhere on earth safe’ from climate change as survival challenge grows – The Sydney Morning Herald

 In Science
As if humans weren’t making it hard enough for the world’s creatures great and small.

Evidence continues to mount that global warming is having an impact on ecosystems across the planet in a myriad of ways, altering both individual species and ecological communities.


Thirty years of Arctic ice decay

Incredible animated video released by NASA shows the drastic change of the Arctic ice shelves over thirty years.

“There’s really nowhere on earth where the natural systems are not being affected by climate change,” Lesley Hughes, a professor of biology at Macquarie University, said.

“Climate change is simply an additional stress on already stressed ecosystems,” Professor Hughes said, listing habitat loss, pollution and over-exploitation among the existing challenges.

A recent paper in Science surveyed research on 94 core ecological processes and found 82 per cent were already revealing climate change impacts as temperatures warmed.

James Watson, a conservation biologist at the University of Queensland and one of the paper’s authors, said people often fixated on polar bears, penguins or another emblematic species.

“They think, ‘that’s miles away from me; it’s a pity but it doesn’t affect me’,” Professor Watson said. “It’s everything that’s affected.”

Here are six key areas of change:

Physiology

Warming temperatures alter the sex ratio of offspring of certain marine and terrestrial species.

As Fairfax Media reported, sea turtle eggs incubate at a uniform 29 degrees, with the male-female ratio changing according to temperature. If temperatures reach 30.5 degrees all offspring will be females. (Should the species survive long enough without males, 33 degrees is enough to ensure no embryos make it.)

The oceans are home to some other big changes, such as increasing acidity as waters absorb more carbon dioxide.

Corals are among the species in the firing line, as are creatures with shells, such as tiny pteropods, the Science paper said.

“Severe levels of shell dissolution” were reported for some Antarctic pteropods, according to a paper in Nature Geoscience.

“As deep-water up-welling and CO2 absorption by surface waters is likely to increase as a result of human activities, we conclude that upper ocean regions where aragonite-shelled organisms are affected by dissolution are likely to expand,” the paper said.

These kinds of changes “have the capacity to undermine and change dramatically the structure of marine food webs, which ultimately underpin much of the protein sources for humans”, Professor Hughes said.

Genetics

Species with short generation spans, such as phytoplankton, are changing fast, but not fast enough.

In the Gulf of Cariaco, off Venezuela, phytoplankton have managed to adjust their ecological thermal niche by 0.45 degrees over a 15-year period. The response, though, lagged the 0.73-degree warming of waters over that time.

For others, such as the southern flying squirrels on North America, hybridisation with “cousin species” the northern flying squirrel is one response. (See image below of northern flying squirrel, via www.nature.ca )

Since 1995, a series of unusually warm winters has marked the start of a northward surge of 240 km in the range of the southern squirrel, the Daily Climate reported, based on work published in Global Change Biology.

Similar hybridisation is evident elsewhere, generating other concerns.

“The interbreeding has several consequences, none well understood: It could increase genetic diversity, helping species weather rapid ecosystem changes,” the Daily Climate said. “It also could dilute the genetics of at-risk animals such as polar bears, perhaps even diluting them beyond recognition. And the changes threaten to wreak havoc with conservation efforts.”

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