Is global warming making hurricanes stronger?
Kerry Emanuel says the debate has ended.
Because of this controversy, and Emanuel’s role in it, Time magazine recently named him as one of the most influential people of the year.
In late May 2006, as hurricane season was poised to begin again, Earth & Sky’s Marc Airhart spoke with Kerry Emanuel about hurricanes, and how we know what’s true.
Airhart: In the 2005 hurricane season, there were an unprecedented 27 named storms. There were more hurricanes than we’ve ever seen since records began being kept, 15 hurricanes in a single season, 7 of which were major hurricanes.
What’s going on? Is it global warming? Or do some scientists still believe that the increased hurricane activity is part of a natural cycle?
Emanuel: I think the idea that it’s part of a natural cycle is dead.
One of the people involved in the original papers about this – it’s like an 80–year cycle, by the way, linking increased hurricane activity to a phenomenon called the Atlantic multi decadal oscillation – that person himself seriously doubts that now. I think it was simply a mistake in how the data were interpreted. I think within a year, that story will be largely finished too.
Airhart: Which scientist are you referring to?
Emanuel: Mike Mann.
Airhart: We still read press releases about this multi decadal cycle.
Emanuel: Yes, and I think people will be forced to back off that in due course. I’m making a prediction.
Airhart: To the public, this sort of debate among scientists is confusing. We hear that maybe global warming is causing stronger hurricanes. Then we hear that it’s just some natural cycle. In a situation like this, how can the average person decide what’s true? In other words, why should we believe you?
Emanuel: I think somebody coming in from the outside of this whole debate, doesn’t have much basis for believing me versus another person. You can look at people’s credentials. But that doesn’t mean anything at the end of the day.
I think what will happen is at some point there will be a strong consensus among the scientists one way or the other. It will be stated as such. At that point, people looking into this debate from the outside will have some confidence in it.
There is a very tiny percentage of scientists who are known within the community to be arguing from an advocacy standpoint. And you can tell. A reasonably intelligent person can tell who those people are. I’m talking about a very tiny percentage. Most scientists are trying ot get an honest answer to these questions, and I’m confident that one will emerge.
So how do you know what’s true? It’s tough. I don’t think there’s a prescription. There are few things in the world where “truth” is something we directly determine through our own experience. Everything else we think we know about the world is received wisdom. And the question always arises: is that received wisdom true?
When we hear about a controversy in science, 99.9 percent of people aren’t participants in that debate. They don’t have any first hand knowledge. So they have to make judgments about what might or might not be true based on a variety of conflicting inputs.
In the scientific realm, as opposed to the political realm, time usually settles these things. Usually it’s a question of waiting.
Airhart: So when it comes to the debate about the relationship between stronger hurricanes and global warming, we just have to wait?
Emanuel: Very definitely. I think this issue, like all scientific issues, will get resolved. I hope sooner rather than later.
As more and more people start to look at it, things will get clearer, because we’ll get better about understanding what we see in the data. And we’ll also start applying better numerical models and computer models to the problem.
Airhart: You weren’t widely known outside your field until your August, 2005 paper in Nature that foresaw more powerful hurricanes like Hurricane Katrina. And now Time magazine has named you one of the 100 most influential people of 2006. Has this new notoriety changed your life?
Emanuel: It has. A lot of people write to me or phone me. They’re all completely well–meaning people and they’re curious about nature. It’s frustrating, because I’d dearly like to be able to talk to each of these people and answer their emails, and it’s become humanly impossible for me to do that.
So it’s forced me to make judgment calls. On the one hand, I want to use the opportunity to convey to the public my understanding of the problem. That’s very much a part of the duty, perhaps even a moral obligation, of a scientist.
But on the other hand, I want to get back to the work, to the research and the teaching. It’s hard to know where to strike that balance under circumstances like this.
To learn more read Kerry Emanuel’s interview on Jan. 20, 2006
