Climate change, flooding and water management

I'm glad you mentioned the, uh, the, the flooding in 2021 and, and also the flooding in Britain because to what extent do you think these are a consequence of climate change, the, the warming of the atmosphere and the, the fact that the atmosphere for every one degree centigrade increase in sea temperature, the 7% increase in the amount of moisture taken up into the atmosphere? I mean, is that broadly correct?

That's nearly correct.

It's the, the air temperature.

So it's the physics of the atmosphere basically means as it warms it can hold more water.

Um, and we know that because we c- we can, um, we can get...

We get clouds forming, for example, when, when you, you pass those, those boundaries in the atmosphere.

And on a cold day, the, the, the air can't hold much moisture, and we might have mist and things like that.

So the more that we warm the atmosphere, the more moisture it can hold, then the more it can rain down on us.

Uh, and, uh, we've seen attribution studies come through which have shown that there is this link between those events being worse, uh, and a changing climate.

Now, it's very difficult with floods to do that type of attribution, and we have to be very cautious about it because once the rain has hit the ground, then it has to deal with the mess that us humans have left on this planet by living in the wrong places, by concreting over our landscape, um, you know, building drainage systems that don't have a big enough capacity.

Uh, so we...

Because humans have modified the landscape and because we are moving around into the path of floods and live on the floodplain, uh, we have to take that into account in terms of the severity of a devas- a disaster.

So when we think about somewhere like Valencia where we had extremely heavy rainfall, we know there's a climate change signal in there.

We've got this underlying baseline warming causing heavier rainfall.

But people were living on the floodplain, and people chose to behave in a, in a way, well, they probably didn't realize they were at risk.

There was, there were not effective warnings out.

They, they went into those underground car parks to try and rescue their cars, and many people died in that situation.

So we do have this climate change signal, but we also have to really pay attention to human behavior and the way that we're planning where we live a- and how we adapt.

So am, am I right in thinking that the, the floods in Valencia, the floods in Germany three or four years ago on, on the, in the Elbe, et cetera, that these are not really one-off occurrences? They're, they're quite likely to become more frequent in the future as, as things warm up.

Yeah, absolutely.

We should be preparing for heavier rainfall and more of this type of surprise flash flood which will be unprecedented, that we haven't seen before.

I mean, the Germany one and the Valencia one are quite interesting because those areas had flooded before, actually quite badly.

Uh, so some of it's about not remembering the past.

Now, we also know that they're going to get worse because of climate change.

But bad floods do happen, and you need this memory longer than human lifespan in order to be able to understand the risk of floods, which places are dangerous to live.