Michael Mann, Director, Earth System Science Center:
Yes. Thanks, Geoff. It’s nice to be with you. It is unfortunate that we are always talking about such very damaging extreme weather events these days. And, yes, there are some effects of climate change that are unfolding rapidly, and with a much greater magnitude than we anticipated, say just a decade or so ago. This is true as ice sheets collapse and sea levels rise. And that’s true with many of these extreme summer weather events that we’re seeing.
And one of the ingredients, of course, you know, you heat up the planet, you’re going to see more intense heat. You dry up the continents in the summer, you’re going to have a worse drought. You mix that heat and drought and you get the kind of wildfires that we’ve seen in recent years in California and across the western United States in the West.
But there’s an additional component that isn’t really captured very well in the models. And it is the behavior of the jetstream that causes these high and low pressure systems to be trapped in place. And when you get one of these deep, high pressures like we’re just out west, over California and the western US, then you get those extremely hot, dry conditions that give you these wildfires. And what is happening is that those systems are getting stuck in place.
So the extreme heat we’ve seen this summer, floods, wildfires, droughts across the Northern Hemisphere, part of what’s going on, is this kind of stuck, jet stream pattern. This is something that we think is being made more often because of climate change, and it is not captured well in the models. This is another reminder that uncertainty is not our friend here.