Clean up is underway in parts of Connecticut following severe storms and flooding recently that resulted in at least two deaths. It's the latest in a series of catastrophic weather events that have hit New England. Most recently, last month in Vermont, and last summer in Massachusetts and again in Vermont.
Such weather events will become increasingly common, according to Dartmouth College Professor Jonathan Winter. In a study last year in the journal climate change, he predicted what he calls extreme precipitation events will increase by more than 50% by the end of the century. He says climate change is driving the increase.
Jonathan Winter, Dartmouth College: As you warm the air, the air can hold more water, so it essentially gives you more fuel in the atmosphere for your storms. So regardless of what triggers that storm, be it a cold front, a low pressure system, remnants of a tropical cyclone as it comes through, it just has more water to work with and essentially more water to dump on the surface.
Kari Njiiri, NEPM: So we can speculate that this is going to be more the norm than, than anything else in the future?
Correct. So that's the observations. We've seen an increase in extreme precipitation. We've been able to attribute a portion of that increase in extreme precipitation to climate change to basically warming our atmosphere. And then we've also done projection. So we've run climate model simulations that look to the end of the century. And there we also see in the results that our air can hold even more water. And because of that we get even more extreme precipitation. So this is not to say that we won't have some years where we won't get much at all in terms of extreme precipitation, and some years like what Vermont's experienced this year, where we get hit multiple times with really bad heavy rainfall events. But overall, as we look into the future over long periods of time, we expect to experience these extreme precipitation events more.
Kari Njiiri, NEPM: What other factors are contributing to this? Is it the terrain in the northeast in New England?
So my research really focuses on what's coming out of the atmosphere. And in that sense, the terrain does play a role because there's lifting that happens as you go over mountains and that can supercharge precipitation. Sometimes storms kind of get stuck in the mountains. They get land locked in the mountains and that can increase precipitation. But when we talk about flooding, the topography is really important because it matters how quickly that watershed floods and how much precipitation it can take. Some of the events that we've had are over watersheds that are prone to flooding because they're relatively small and steep. And then you also have to consider how much precipitation we've gotten over the past couple of months, because if you have a really wet soil going into a heavy rainfall event, there's no other place for that water to go except to run off and go into your rivers and cause flooding. Whereas if you have, you know, an average type of rainfall, there can be some room in the soil to absorb some of that water.
Kari Njiiri, NEPM: So when it comes to solutions, how should state and federal governments prepare for this increase?
It's a good question. And obviously states and towns have their own competing interests, and it's not something for me to really step into easily as a climate scientist and say, you should do this and you should do that. What we have been doing is we have been trying to conduct that outreach and work more closely with stakeholders that are interested in understanding how extreme precipitation is changing, and then it's really their domain of expertise, or it's what they have knowledge on, and I don't. To figure out how best to adjust the infrastructure to handle this new normal.
Kari Njiiri, NEPM: I don't know if you can speak to this in terms of some of the ripple effects on, I'm thinking, mosquito and tick borne illness. Could we be seeing an increase in in these incidents as well?
Yeah, there's a plausible mechanism for that. Another piece of my research portfolio is looking at how Lyme disease has changed, both historically and how we projected to change into the future. There's a lot all changing at once. So New England has experienced a dramatic change in land use even since the 1900s. And then we also have this shifting climate. So it is very difficult to disentangle to what extent when we talk about, say for something. And this is the one that I'm most familiar with, the risk of Lyme disease, whether it's land use change. So we've just created some great habitat for ticks or we've killed off some of the predators.
Ticks like mice and mice help pass Lyme disease. So it's this whole chain of which climate is just one chunk. And wetter climates are advantageous for ticks. They don't like it to be dry. It knocks tick populations down because the tick essentially dries out. Same thing with mosquitoes. Maybe they don't dry out, but they don't have the same kind of, um, habitat. But I think those links are more difficult to make. And we're trying to do it, but they're more difficult to make relative to like, what's falling out of the sky.
