Hurricanes are getting more powerful and more destructive because of global warming, which gives storms more energy, but as the mass media reports on the destruction, they leave out this connection. Climate scientist Kevin Trenberth explains the link
MARC STEINER: Welcome to The Real News Network, I’m Marc Steiner. Good to have you with us.
Florence is one of the most massive and dangerous hurricanes to ever hit this far north, and it’s about to hit the coastline of the Carolinas and Virginia. It’s the size of Colorado with winds of at least 140 miles an hour. Some think Florence should be Category 6 as a hurricane, that category doesn’t exist yet. This massive hurricane is about to hit an area filled with nuclear reactors and toxic waste dumps. Most of the reporting on this massive hurricane and others have not mentioned climate change as a factor in either the frequency or the intensity of such hurricanes. Kieran Bhatia from Princeton University recently published a study making just that claim.
So, while that remains a little bit of a controversy among some climatologists, we’ll discuss how the warming of our oceans, a fact created by climate change is a factor or can be a factor in the increasing intensity, size and velocity of these storms. We’re joined by Dr. Kevin Trenberth, who is one of the world’s leading climatologists, who is part of the Climate Analysis Section at the National Center for Atmospheric Research and was a lead author in 2001-2007 of The Intergovernmental Panel on Climate Change’s report, or as we know it more commonly, IPCC, on just this issue. And Dr. Trenberth, welcome. Great to have you here with us on The Real News.
KEVIN TRENBERTH: Thank you very much for having me.
MARC STEINER: So, I’m glad you’re with us. And let’s start here with a broad question we’re not seeing on the news very much in any of the news reports, which is the connection, the arguments behind connection between climate change, the warming of the oceans and the intensity of these hurricanes. So, how can you parse that out for us?
KEVIN TRENBERTH: Well, humans are producing climate change by mainly interfering with the natural flows of energy through the climate system. So, there’s a buildup of heat-trapping gases in the atmosphere. Carbon dioxide is the main one, but there are some others. And these provide an extra blanket, so there’s extra heat available in the system. Most of that heat ends up in the ocean, over 90 percent of it in the ocean, the oceans are warming. In fact, the best single indicator that climate change is happening is the changes in the ocean heat content. The second best is the rising sea level. So, sea level is going steadily upwards and the variability from one year to the next is relatively small compared with all of the weather that normally occurs.
And so, we’ve got very clear evidence that the oceans are warming. In 2017, the oceans as a whole are the warmest on record for the calendar year. And for the last quarter that we’ve got complete measurements for or complete analyses for, from April to June- April, May, June, that’s the warmest quarter for the global oceans on record. And some of the warmest spots certainly move around from one year to the next, and at the moment, one of the warmest spots is out near where Florence is occurring. And so, it’s not just the surface, the sea surface temperatures, but also the ocean heat content, all of the warm ocean beneath there that is providing support for energy flowing into the storm.
MARC STEINER: So, what I’ve read, and maybe you can clarify this for me, what I’ve read is that there’s is a natural process where the oceans warm up that helps cause hurricanes to take place that has to do with interaction with the atmosphere. But what’s happening with the warming of the oceans, at the depths of being that the warming is taking place, that this is what’s causing the intensity of these hurricanes to increase? I mean, it’s like a natural phenomenon gone haywire because of global warming.
KEVIN TRENBERTH: Yes. And so, the oceans are warmer by more than one degree Fahrenheit since 1970 as a whole. And then you add on a little bit of extra natural variability in the moment there, in that vicinity there, at least three degrees warmer than normal. For every one degree, you get about four percent more water-holding capacity in the atmosphere. And so, in that region, there’s something like ten to fifteen percent more water vapor capability for the atmosphere to hold that amount. And that increases the evaporation from the ocean, this provides the extra water vapor that gets caught up in the storm and produces heavy rainfalls. When those rainfalls occur, the heat that gets released, that originally went into the evaporation, is the actual fuel for the storm.
And so, this leads to a more intense storm and over time, the storm can grow bigger. And it did that in an episode last night as the spiral arm bands spiral around the storm and then cut off the supply to the original eye to the storm, and then the eye grows bigger and these storms grow bigger over time. This is what happened last year with Harvey and Irma and Maria as well. And so, this is another storm in those kind of categories. And the consequences if it really goes slow, as it did with Harvey, are really prodigious amounts of rainfall.
MARC STEINER: So, a couple of quick questions here before we conclude. Chris Lancey from the National Hurricane Center questions whether or not we really have enough data to say that there is a real direct correlation between the warming of the oceans and the intensity of hurricanes, that the models are not- we don’t have enough evidence. So, there clearly seems to be some differences between some climatologists. Can you speak to that, why the differences exist and what do you make of those arguments?
KEVIN TRENBERTH: Yes. And so, there’s tremendous amount of natural variability in hurricanes. From where they occur, there’s always a competition between the Pacific versus the Atlantic. In El Nino conditions it’s much warmer in the Pacific and the action is all out there and it suppresses the activity in the Atlantic. Where they occur certainly varies from one year to the next. Last year the Caribbean and the Gulf of Mexico was very, very warm and ot led to Harvet and Irma and Maria. But those storms actually took a lot of heat out of the ocean and cooled off that region, which is one reason why that that area is not as active this year, but instead we’ve got this region out where Florence it at the moment that that is producing a very storm.
So, you can’t deal with it from the standpoint of the statistics because the variability is so large. What we can deal with is the overall changes in the sea temperatures and the ocean heat content, and those are systematically higher than they used to be. We can measure that, we can track it over time and we know the consequences. The consequences are that there’s more moisture in the atmosphere and it provides more fuel for the storms. And so, the argument is more from our understanding of the science and how these storms work, rather than from the statistics, which reliably, we can only go back to about 1970 because before then we didn’t have satellites. And so, we just don’t have a long enough record to deal with the large variability in any basin to address the questions that Chris Lancey was asking.
MARC STEINER: So, then when people kind of question the relationship between climate change and the intensity of hurricanes, how do you respond to that and how should we respond to that? I really want to get to the heart of that.
KEVIN TRENBERTH: Yes. So, the the real response is that the environment that all of these storms are occurring in has changed. The sea temperatures are warmer, the ocean heat below the surfaces is warmer, there’s more water vapor in the atmosphere and the consequence is that there’s heavier rainfalls. And we’ve got excellent statistics on the heavier rainfalls, because rainfall is occurring all of the time, whereas hurricanes are episodic events. And so, we have excellent statistics that when it rains, it rains harder than it used to. And hurricanes certainly produce some of the most prodigious rains, and therefore that’s the thing to really watch out for in this particular event, the risk of extensive flooding.
MARC STEINER: And it also seems to be that this particular hurricane, Florence hitting the Carolinas and Virginia where it may hit, where it seems to be headed towards at this moment, is that’s also a place where, from what I’ve been reading this morning, there are a lot of toxic waste dumps, there are a number of nuclear reactors. And I mean, this could be a very dangerous pattern we’re about to see.
KEVIN TRENBERTH: Well, it could be indeed. And the preparation that can be done in all of these sorts of areas protecting those areas from being washed away- as they did actually down in Houston last year with Harvey, there was one area that also produced a lot of contamination because of that. But all of these areas are under this kind of risk and it’s really irresponsible that they’re vulnerable in this regard. The Navy has sent all of their ships out to sea, as I understand it, to get them out of the risk zone, there ought to be strategies for dealing with this kind of thing. It means that you can’t just do it in the one or two days ahead of time, there ought to be preparations for this kind of thing well in advance, and that’s the thing which is not happening adequately at the moment.
MARC STEINER: Let’s conclude this portion of it, because I’m very curious about conversations you and others may have around this particular issue of even if we all of a sudden magically woke up tomorrow morning and decided we were going to end our fossil fuel-based world and move to a cleaner energy economy, it would take decades and decades to even things out, even come close to it if we could. So, what do we have to consider? Because If these hurricanes continue with this intensity and keep growing, whether they occur in the Caribbean as last year occur in the mid-Atlantic as they’re happening right now, what is it we have to begin to think about?
KEVIN TRENBERTH: Yes. So, the carbon dioxide that’s going into the atmosphere has a very long lifetime. Some of it lasts for centuries. And so, even if we stop putting more carbon dioxide into the atmosphere now, and we’re not going to do that but we can certainly slow it down, which would be beneficial, the carbon dioxide that’s already there is going to remain for quite a number of years. So, we’re going to have to live with the consequences of what we’ve already done to some extent. That means we need to prepare for it. We need to adapt to it. We need to build resilience and so on.
But at the same time, we do want to stop the problem from getting even worse as we go further into the future. So, another twenty years from now the temperatures will maybe be even a lot higher and the risk of what we might call Category 6 storms would be then an annual event. And so, we need to do the do both. We need to try and prevent things from getting even worse, but we also need to recognize that we’ve already got a problem. Climate change is with us and we’re seeing consequences already.
MARC STEINER: So, one last quick question then. So, there’s no question in your mind that climate change is a factor, as we know in the warming of the oceans, but the intensity of these hurricanes, A. And B, do you think we should begin talk by Category 6 sized hurricanes, which some people do not want to do yet?
KEVIN TRENBERTH: Well, yeah. So, I mean, we have category five storms and this one is a Category 4. It could become a Category 5 briefly. But Category 5 is actually wide open at the end. And already we’ve had major storms over in the Pacific. There’s one that just went through near the Philippines, in fact. And there was one that hit Japan fairly recently. And so, the big typhoons are bigger than some of the hurricanes that we’ve had in the Atlantic. So, these things are already, to some extent, a reality, and there’s a large element of chance as to just where these storms go, where they hit. A lot of that depends upon the weather, the weather situation; where the jet stream is, where the cold fronts are and so on like that.
And so, there’s certainly an element of chance involved in all of these things, but the risk of these storms being more intense, somewhat bigger and with really heavy rainfalls- and in coastal regions of course also the storm surge matters a lot, and that’s because the sea level is higher, as well, in part because of climate change. And so, all of these factors are ones which we need to start taking notice of.
MARC STEINER: Well, Kevin Trenberth, thank you so much for joining us today on The Real News Network, was a pleasure to talk with you. We needed the information, appreciate you sharing it with us.
KEVIN TRENBERTH: Thank you, you’re welcome.
MARC STEINER: Take care, have a lovely day.
KEVIN TRENBERTH: Thank you.
MARC STEINER: And I’m Marc Steiner, here for The Real News Network. Thank you so much for joining us. We’ll stay on top of this for us all. Take care.