Message from a dead frog

I once had the good fortune to discover a new species of frog. It was neither large, nor flashy but was extremely rare, living only in a hectare of boggy grassland at the foot of a huge waterfall. Five years later it was extinct – a victim of man-made climate change.

The brownish-yellow frog just two centimetres long, had lived for time immemorial at the top of a steep gorge in the middle of a remote mountain range in Southern Tanzania. In this secluded froggy paradise it passed its days peacefully hopping about in the grass, or clinging in its thousands to the side of giant boulders buffeted by the driving wind and rain from the waterfall.

Its problems started* one afternoon, around tea-time, when the three giant turbines of the Lower Kihansi Hydropower plant were switched on for the first time to start providing power for the afternoon rush in Dar-es-Salaam.

When that happened, the river was diverted, the giant waterfall dried up, and the climate of the frog’s habitat changed dramatically. Rainfall instantly dropped to less than one percent of what it had been. Temperature immediately shot up a couple of degrees, then continued to climb several degrees higher over the following hours.

Standing there when it happened, the change was unmistakable, and came as a bit of a shock - not least to the frogs who died in their thousands. What was maybe more surprising** was the change I felt in the area when I returned a year later. The diversion of the river had affected the character of the entire gorge – not to the same extent as in the frog’s habitat – but the roar of the river had gone, and the air beneath the trees sat heavy, hot and still. I clearly remembered how the local microclimate had felt, and the contrast was unsettling.

The worrying thing for me is that the temperature change I experienced over one year is not so different to the one that the human species has experienced over the last couple of centuries. And it’s likely to be less than the one we’re going to endure over the next 30.

So why isn’t everyone as shocked by these climate changes as I was?

Of course, it doesn’t help that the transition has been so slow (in human terms), nor that our appreciation of subtle temperature differences is so rudimentary. Because the change we’re experiencing globally is largely gradual and incremental, we don’t notice it on a day-to-day basis, and so it gets subsumed beneath the endless daily concerns which clamour more immediately for our attention.

Another problem is that our thermal memories are rubbish as well. If we could feel the difference in what the average temperature was ten years ago in comparison with today maybe things would be different. But we can’t.

Instead, it takes rapid changes to jolt us into action. It’s the Hurricane Katrinas of this world that get things altered, precisely because we can clearly see and remember how things were before, and how they are after. No wonder that so many environmental campaigners, in the dark and slightly guilty secrecy of their unspoken dreams, hope for some zero-casualty but big-impact climate shock to shake people up a bit.

Of course, when that happens, it may already be too late, as it was for Nectophrynoides asperginis. They say frogs in cooking pots fail to notice the rising temperature. You can’t avoid the comparison as we sit here, slowly being boiled whilst contentedly blinking in the rising heat.

*Of course, their problems had actually started a couple of decades earlier with the Tanzanian hydropower capacity assessment study, but frogs don’t generally have access to that sort of information, and no-one knew they were there to consult them anyway, so as far as the frogs were concerned, the first they knew about it was when it was too late.

I should add that, technically, it was a toad rather than a frog, but having been plunged into the amphibian world, one of the first things you learn is that it’s always acceptable to call a toad a frog, but not vice versa. For the purposes of historical accuracy, I should also point out that my contribution to the discovery didn’t really stretch beyond asking “what are all these yellow jumping things” as another small cloud of them leapt out from beneath my descending boot. By that time the proper scientists in the party had already secured a couple of handfuls of them in the cloth bags hung from their belts. Thanks to their efforts, although the frog is extinct in the wild, a few survive in captivity in the Bronx and Toledo zoos.

**For me at least. Sadly the frogs themselves were somewhat beyond surprise by this point.