Erratic Weather or Climate Change?

Meteorologist Bob Henson discusses the latest science regarding climate change and extreme weather, including what may be causes.

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JARED BALL, PRODUCER, TRNN: What’s up world, and welcome back to the Real News Network. I’m Jared Ball here in Baltimore.

It’s been a crazy six months in climate change, or weather as those on the right often like to call it. Smashing all previous records globally, June was the hottest it has ever been, and 2015 is on track to be the hottest year since global record keeping began in 1880. From record-breaking global temperatures, including the worlds’ oceans, to arctic melting to sea level rise, as well as flooding, global droughts, forest fires and hurricanes, mother nature continues to speak to us about what she sees going on here. And people as far afield as Naomi Klein and the pope are sounding their own alarms about climate change.

But can we attribute all this weather mayhem to climate change? Here to walk us through it is Bob Henson. Bob Henson is a meteorologist and science blogger at Weather Underground, and the author of the Thinking Person’s Guide to Climate Change. Welcome, Bob Henson, to the Real News.

BOB HENSON, METEOROLOGIST: Thank you, Jared.

BALL: So let me just ask you that question as I mentioned in the intro. First, could you comment a little further on the changes you see occurring around the globe, and the cost and the impact in terms of damage? And then are these shifts the result of climate change?

HENSON: Sure. Well, a lot of what we are seeing is related to climate change. It’s tricky to parse out exactly which pieces at times, and some things are more closely related to climate change than others. Certainly the global temperatures over the last 100 years have warmed as a result of what we are putting into the atmosphere. We’re really seeing that come to fruition this year, as you noted June being a record high for any other June going back more than 130 years.

We’ve actually seen four of the last five months all set global records for those months. For example, February was the warmest February on record, March for March, May and June as well. So we are more than on track this year to set a global temperature record. And there’s a pretty firm connection between the amount of greenhouse gas we put in the atmosphere, it’s actually on the order of half a trillion tonnes now historically, a pretty firm connection between that and the warming.

Now, when you get, drill down to individual weather events it’s a little harder because there are so many variables that go into causing something like a thunderstorm. You need moisture, you need heating, so forth. And some of those are related to climate change. Some aren’t, particularly. There’s a whole industry of research called attribution and detection research that focuses on those problems.

In general terms the heat globally is most closely related to climate change. Also there’s a tendency now to get heavy rains and heavy snows in more concentrated fashion. So the amount of rain or snow you get in a city may be more likely to occur now in a few big events and separated by longer dry periods, along with that when there is a drought going on such as California, the impacts of these droughts are becoming worse.

Now, the lack of rainfall is not necessarily historic. It’s been very dry the last several years in California, but there have been historical periods [inaud.] this century that appear to have been [this dry]. But the temperatures associated with the heat are off the chart setting records. And it’s the temperatures that cause the lack of snow cover in the winter, and evaporation, loss of ground moisture and such. So it’s real important to separate out what is climate change and what is simply weather and climate. So a lot of people are working hard on that.

BALL: Well speaking of which, we know that historically there has been somewhat of a struggle with scientists linking severe weather events and change to climate change. Are there any, is there any latest research that suggests that this is changing?

HENSON: Well, I think scientists are by nature cautious and that’s a good thing, because you don’t want to go out on a limb as a scientist and then have the limb sawed out from behind you. I think again it takes a lot of research. And it’s a very, a very complicated thing to show the connection between climate change. Because climate change as we think of it or global warming is caused by greenhouse gases that sift out over the entire earth, and they affect whether and climate for decades, even centuries.

Now, that changes the whole environment that we kind of marinate in, but it’s entirely another thing to say okay, this caused a tornado or a hurricane, or something like that. So the attribution research I’ve been talking about is usually done in terms of probability. Looking at things like what are the odds that a particular El Nino is stronger, or what are the odds that the heavy rains that occurred in Texas or Oklahoma in May are related to climate change.

That kind of work does produce results. It takes time. For example, the heat wave in Europe, a devastating heat wave in 2003 that killed upwards of 50,000 people prematurely, the odds are about twice as likely that that heat wave occurred than it would have been if we didn’t have global warming occurring. In other words, the greenhouse gases we put into the atmosphere made that heat wave at least twice as likely.

A lot of these things could still happen without climate change, they’re just becoming more likely. If you take a dice and make five of those sides a six, and the other one is a one, you’re going to roll six more often, right. So that’s how we like to look at climate change, is the odds are rising of certain kinds of outcomes. Heat waves are becoming more likely. Cold waves less likely. But we can’t point to a certain heat wave and say that was climate change.

Really everything is now in an atmosphere that is changed. And so it’s all, the context has all changed. But the individual weather events, we’re still going to have weather, we’re still going to have things like El Nino. So it’s just a matter of how will the odds of those shift. Kind of how will the wardrobe that we have, the weather wardrobe you might think of it, how is that evolving? We’re going into an environment where we’ll need more t-shirts and fewer long-sleeve shirts. I think that’s a good analogy.

BALL: So in the run up to this December’s Paris-based talks about developing a major, binding agreement on global temperatures, what do you see is the best case scenario for preventing these temperatures from continuing to rise to dangerous levels?

HENSON: Unfortunately we’ve got a fair amount of climate change already kind of baked into the system. Because the oceans have absorbed a lot of heat that we’re not even aware of. In fact, something like 90-plus percent of all the heat that’s been trapped by the extra greenhouse gases has gone into the oceans. So we may not notice for a long time, but eventually the oceans give that heat up.

So we’re pretty much guaranteed to warm at least another degree Fahrenheit simply because of what we’ve already done. We can’t change that aspect of climate change to come, but we can keep it from being worse. And that’s the critical importance of coming up with some kind of emissions system where there’s a motivation for all the nations of the world leading emissions producers to cut back, and there’s lots of different ways of thinking on how that should be done. I think clearly the marketplace has to be involved in one way or the other. I think you also need some big sticks as well as big carrots.

You’ve got to have some kind of global agreement in particular I think to set a price on carbon. Because if carbon isn’t priced out based on the impact it has on the globe then you really can’t go any further in terms of capitalist systems.

So I think the important thing in Paris this December at the UN agreement will be for nations to agree that we really need to come up with a benchmark above which we can’t let the climate warm. The most common one that’s cited for that is 2 degrees centigrade. That’s about 3.6 degrees Fahrenheit. We’ve already warmed at least a third of the way to that benchmark. The earth has warmed more than a degree Fahrenheit in the last 100 years. So we’ve got it, try to keep it from that level. Because a lot of research shows that once you get much above that level a lot of the more catastrophic outcomes become a lot more likely. Sea level rise that in the next couple centuries could swamp some of our best-loved cities and important landscapes for humanity. So those are the outcomes we’re looking at trying to keep at bay, I think the ones further out that will affect our grandchildren, great grandchildren, and so forth.

So in Paris, I think if the nations of the world can agree–there’s already been an agreement back in 1992 signed by President Bush and virtually all the other leaders of the world that we need to prevent dangerous climate change. The tricky part is what exactly is dangerous? And the push now in Paris is to define dangerous as those 2 degrees centigrade. If that can happen then there’s a lot of ways in which the governments of the world can then agree okay, well, to get to this point then we have to restrict X amount of carbon, and here are some of the ways we can do that.

And again, I think some kind of a global agreement on how much carbon needs to be priced at is crucial. Because let’s say that the U.S. cut way back on our emissions. Then the cost of oil and gas might go down and other countries might burn more. Or vice versa. We might burn more if the price goes down because of cutbacks down in other countries. So you’ve got to have those systems in place so that there aren’t perverse incentives for some countries to just burn a lot of oil.

In fact, China has actually leapfrogged over the United States as the leading emitter of carbon in the last decade. The U.S. used to emit about 30 percent of it globally, China was 15. It’s pretty much reversed now, the U.S. 15, China’s 30. China’s doing a lot of good stuff on emissions reductions, but they’re also four times the size of the United States. So it’s really going to be up to the U.S., China, Indonesia, some of the other global emitters, to cross some of these bridges that separate us, to look at our historical responsibilities and our current responsibilities and future ones.

It’s not an easy process, and I’m kind of a worried optimist. I was at the Copenhagen summit in 2009 and very depressed at how that one went. So I’m keeping my fingers crossed that we can make some progress this time.

BALL: Thank you, Bob Hensen, for joining us here at the Real News and helping us work through this. We appreciate your time.

HENSON: Thank you Jared, appreciate it.

BALL: And thank you for joining us here at the Real News Network. And for all involved, I’m Jared Ball here in Baltimore saying as always as Fred Hampton used to say, to you we say peace if you’re willing to fight for it. Peace, and we’ll catch you in the whirlwind, everybody.

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