Before the flood

People tend to think of climate change in terms of it getting hotter, which makes sense of course, but the systemic effects of higher temperatures are much broader. Here’s an interview with four climate scientists that discusses the connection between higher temperatures and increasing precipitation:

Richard Seager, Columbia: In general, we know that heavy intense precipitation is increasing pretty much everywhere around the world, as a result of rising atmospheric temperatures.

There’s never a complete one-to-one relationship between heavy intense precipitation and flooding of rivers. But you could certainly say that heavy, more heavy, and intense precipitation is more likely to cause the kinds of flooding that we’ve seen.

We know from climate models, and just simple theory, that the atmosphere can hold more moisture as it gets warmer. We’ve known that … this can happen for decades now and it’s really coming true.

Daniel Swain, UCLA: Let’s back up a little bit. Before we get to flooding, let’s talk about extreme precipitation. That’s sort of what the proximal cause is with terrestrial flooding, as you get too much water too quickly from the sky, in the form of rain generally.

One of the signatures of climate change is an increase in both extreme heat and extreme precipitation. And this is true almost everywhere.

This is exactly the kind of event you’d expect to produce extreme precipitation in the [New England] region — a slow moving, very moist storm system. . . .

Richard Seager, Columbia: The lesson looking forward is to start planning for how we’re going to adapt to things that we have just never seen before.

[We need to think about] how populations are going to deal with extreme heat, how our infrastructure is going to deal with extreme precipitation and flooding. We’ve got to think through all of that and start making changes now based on what we expect will happen in the future.

What we’ve already done to the climate system is going to lead to more warming going forward. So a lot of these changes we’re talking about in the near term are pretty much inevitable.

Whatever we do in terms of prevention can certainly prevent it from getting as bad as it otherwise would. And the payoff in decades to come will be huge.

But by getting serious about reducing emissions right now, we’re not going to get out of this problem immediately because we have so much heating of the climate system that’s currently in the pipeline.

Mohammed Ombadi, University of Michigan: There is little that can be done at the individual level. Most of the efforts needed for adaptation must be taken at the local, state, and federal government levels. However, people can cope with those flooding events by avoiding building homes in regions that are vulnerable to landslides and hill slopes that can be severely impacted by such torrential downpours.

​​The big message here is that our infrastructure was designed for a climate that no longer exists. This is very clear with the ongoing floods in northeastern US as we hear news of washed-out roadways and bridges, damaged tracks in railroads, and swamped homes. We need to change the way we design and build infrastructure to be in line with the increase in rainfall extreme events predicted by climate scientists.

That we live in a world designed for a climate that no longer exists becomes more evident with every year, and indeed every season. What’s really sobering is that the climate that exists now will not resemble that which will exist a generation from now, and so forth.

How our societies and political systems deal with all this is almost certainly going to be the central question of the 21st century.