Stardate 20020327.0825

(On Screen): An environmental scientist claims that a 1-degree rise in world temperatures will doom a species of lizard called the Tuatara to extinction. This species has existed since the time of the dinosaurs. So "someone" better ratify the Kyoto accord, hadn't they?

For her research Ms Nelson artificially incubated 320 tuatara eggs at temperatures of 18, 21, and 22 degrees Celsius. At 21 degrees Celsius she obtained 96 per cent females. At 22 degrees, she obtained all males. At 18 degrees, the offspring were all female.

"It's a very small temperature change that makes a difference to the sex ratio and that's important because if global warming is a reality, they're talking about temperature changes...up to 5 degrees Celsius," says Ms Nelson.

The problem with the supposition is that it can't be right. If the Tuatara were that vulnerable to global temperature changes, it would already be extinct. How, exactly, did it survive the last ice age? Or the periods in the past when the temperature was dramatically warmer than it is now?

The flaw in her experiment is obvious: she did her incubation at constant temperatures. But in the wild, the temperature fluctuates daily, getting warmer in the day and colder at night. (I seem to recall...)

"What I want to work on now is how it actually works in nature," says Ms Nelson.

Good plan.

I'm glad she recognizes that her results don't square with reality.