IF you’ve not seen it in the wild then you’ve probably seen it on telly – lizards sat out in the daylight, sunning themselves when there’s surely some housework to be done.

So to the ignorant or uninformed (I’m one of them), you’d think that warmer global temperatures would just mean more fun in the sun for the world’s lizard populations. Not so, according to a new study in Science.

Australia lizard extinctions 2009

Even though lizards do love to warm up in the sunshine before going off to find food, they all have a point at which they’ve had enough.

Higher temperatures can force them to run for cover, which the international team of researchers explain cuts down the time they can spend foraging for food.

The researchers first looked at this physiology in the lizard and then developed a model taking into account rising temperatures across the globe.

They then used the model to see if it matched observed extinctions in 2009, which in Australia look like this first map. The model replicated their observations of extinction rates on five continents. Next, they used the model to see what will happen if emissions of greenhouse gases and, in correlation, global temperatures, both keep rising.

Then, the extinction rates for lizard populations looks like this. First for 2050….

… and then for 2080.

On a global scale, by the year 2050 the probability of any species becoming extinct was 6 per cent and by 2080, it was 20 per cent, the study concluded.

But with all those other pressures on lizards such as disease and human population growth, couldn’t those extinctions be just as easily blamed on something else? Lead researcher Professor Barry Sinervo, at the University of California, says:

We did a lot of work on the ground to validate the model and show that the extinctions are the result of climate change. None of these are due to habitat loss. These sites are not disturbed in any way, and most of them are in national parks or other protected areas.

The loss of lizards isn’t just bad for, well, lizards, but researchers said it would also have an impact up and down the food chain. Lizards represent food for other animals as well as keeping the insect population in check.

Sales of lizard sunscreens and shade umbrellas (also used in cocktails), could receive a boost, no one said.

Map images: Barry Sinervo.

PrintShare