Is Climate Change Real? For the Thousandth Time, Yes

| May 3, 2012
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In January of this year, snow was still sparse at high elevations in the Sierra Nevada. (Molly Samuel/Climate Watch)

From PBS NewsHour yesterday, a story about the difficulties teachers confront when discussing climate science in the face of both skeptical parents and hostile state laws.

From the report:

CHERYL MANNING, high school science teacher: They hear it on the news. They see it in the newspaper. They hear their parents talking about it. There are people who say that climate — the climate may be changing, but it’s not our fault, or the climate isn’t changing at all; this is a natural cycle. There are all sorts of things that the kids hear. They want clarification.

HARI SREENIVASAN, PBS NewsHour: In fact, in a recent survey by the National Science Teachers Association, teachers say they’re facing skepticism about climate science; 82 percent of science teachers say they faced it from students, and 54 percent say they faced it from parents….

SUSAN BUHR, outreach director, Cooperative Institute for Research in Environmental Sciences: Teachers in science classes are always going to want to talk about the science. And, increasingly, it’s difficult for them to do so because of resistance from parents or from students to hearing about the evidence of climate science and climate change.

“Polls say 97 percent of working climate scientists now see global warming as a serious risk” according to a recent article in the New York Times. But 42 percent of respondents in a March Gallup poll said the “seriousness of global warming” was “generally exaggerated.” And while 61 percent said the effects of global warming were “already happening” in 2007, that number has now dropped to 52 percent.

Recently, I asked Craig Miller, Senior Editor of KQED’s Climate Watch, to go back to basics and review, once again, the evidence, that shows the earth is warming, and what the likely effects of that will be…

BROOKS: So what are the organizations that say climate change is real?

MILLER: Virtually ever major, credible scientific organization in the world. It’s not just the UN’s Intergovernmental Panel on Climate Change. Organizations like the National Academy of Sciences, the American Geophysical Union, the American Association for the Advancement of Science. And that’s echoed in most countries around the world. All of the most credible, most prestigious scientific organizations accept the fundamental findings of the IPCC.

The last comprehensive report from the IPCC, based on research, came out in 2007. And at that time, they said in this report, which is known as AR-4, that there is “very high confidence” that the net effect of human activities since 1750 has been one of warming.

Scientists are very careful, unusually careful, about how they put things. But then they say “very likely,” or “very high confidence,” they’re talking 90%.

BROOKS: So it’s not 100%?

MILLER: In the realm of science; there’s virtually never 100% certainty about anything. You know, as someone once pointed out, gravity is a theory.

BROOKS: Gravity is testable, though…

Virtually every major credible scientific organization in the world says climate change is real.

MILLER: You’re right. You can’t drop a couple of balls off of the Leaning Tower of Pisa to prove climate change. That’s why we have to rely on mathematical models to try to figure out where this is all going. And that’s difficult.

But it’s not impossible, as some people like to paint it. You know, the people doing the models are not inept. Over the past nearly four years, Climate Watch has interviewed a lot of scientists, attended conferences, read academic papers. To me, as what you might call an informed observer, the vast preponderance of scientific evidence supports this notion that the Earth is warming and that human activity is a significant cause.

BROOKS: Are there legitimate debunkers of this proposition?

MILLER:  Certainly there are legitimate scientists on the other side of the question. If you take, for example, a guy by the name of John Christy from the University of Alabama, who is very strongly identified with climate change skeptics. That doesn’t mean that his work is invalidated.

He came out recently with a study that basically refuted the idea that there’s been an observable shrinkage in the snow pack of the Sierra Nevada. And we talked to other scientists who do believe in anthropogenic or human-induced global warming and do believe that the Sierra snow pack is going to be shrinking, who thought that this study was sound.

But that’s one study in a sea of studies. And you have look at the preponderance of the evidence and not at any one particular study, not any particular year, not even any particular ten years, because even a 10-year trend does not necessarily constitute climate change.

BROOKS: What are some of the metrics scientists have looked at to come to the conclusion that human-caused climate change is real?

MILLER: They study temperature records. There have been tidal gauges in place for a long time, looking at sea-level rise, and also augmented now by satellite data that measure with greater accuracy the rate of the rise. They’ve looked at things like ice cores from Greenland and elsewhere which gives us sort of a reverse chronological story of what the climate has done. And you can actually pull one of those ice cores and see the amount of C02 that was in the atmosphere at the time. And what they’ve found is what looks to be a pretty convincing relationship between the amount of carbon dioxide in the atmosphere and the behavior of the Earth’s climate.

BROOKS: But there are some who refute that evidence?

MILLER: Absolutely. We’ll get people frequently commenting on our blog who will say the sea level is not rising and that there’s been no warming for the past ten years.

As I already pointed out, ten years of anything does not constitute a definitive pattern; it’s just too short a time span. It’s this idea of cherry-picking data, which both sides accuse the other of doing.

You have to look at the Earth’s climate over time as a really big, complicated jigsaw puzzle. And clearly there are pieces missing. And there are pieces sitting off to the side that aren’t missing, but we don’t quite know how they fit into the puzzle yet. But still, you see enough of the picture to know what’s going on.

The science has yielded at least — as Stanford’s Chris Field of the IPCC puts it — a blurry picture of the future. And the blurry picture is enough to know the general direction we’re heading, even without knowing all of the specifics.

BROOKS: Are there former critics who now acknowledge the reality of climate change?

MILLER: Richard Muller would be a good example of that. He’s the physicist over at UC Berkeley who was identified with the skeptic camp for a long time. He wasn’t buying a lot of climate change theory.

He launched a temperature-data audit because he wasn’t convinced that the temperature data being used by the IPCC and NOAA and others was accurate, that there were fundamental issues – they were getting bad data, garbage in, garbage out.

So he went back and did an audit of the program, and when called to Capitol Hill to testify before a mostly-Republican committee, they were very disappointed to hear him say well, actually they’re right. We’ve gone back and the work we’ve done to try to verify the data shows that actually they’re using good data, and warming does appear to be happening.

BROOKS: What do the polls say about the public’s belief?

MILLER: Well, there’s a certain ebb and flow to the polling, and I think it’s influenced by a lot of things. Some people try to oversimplify the reasons for why people think the way they do about climate change. But a recent poll that we saw found the highest percentage of people who are accepting that climate change is real. The pendulum was, in other words, swinging back towards more people accepting the prevailing climate science, to 62%.

That was the number for the fall of 2011, which, which is the highest it had been since the fall of 2009. And, and then they went on to ask them for reasons for their views, the two biggest factors cited had to do with the weather. Warmer temperatures and general weather changes.  About half of the people who were polled said one or the other of those two things.

That’s a clear example of “the tyranny of the present,” which is a major factor in the public response to climate change. People tend to believe whatever it is that they’re seeing around them right now, or have observed in the recent past.

You know, if it’s an unusually warm winter, you get more people thinking that the Earth is warming. If you have an unusual cold, snowy winter — and by the way, snow can be very confusing on this point because more snow very often is an artifact of warming — but you have an unusually and snowy winter, then ewer people believe in global warming, and you see the signs start to go out in the snow banks, you know, “what global warming?” and that sort of thing.  The public has a very short memory.

There are many other reasons that influence people’s views on global warming. Some are ideological. Some are religious. Some are economic. People that have a personal economic stake in or perceive that their ox would be gored by the necessary policy responses to global warming often oppose them and tend to not believe in the concept. Basically, people tend to believe what they want to believe.

BROOKS: So is there a concerted campaign to debunk climate change theory?

MILLER: Yes, and very well documented. There’s a very determined and well-funded attempt to forestall action on climate change by casting doubt on the science. This is a time-honored tradition in our country; think of the Tobacco Institute. It’s a page from that playbook, basically.

BROOKS: So what’s going to happen as a result of global warming?

MILLER: I can tell you that there are a certain amount of impacts already baked in, no pun intended. Because, even if we didn’t burn one more lump of coal, scientists say there’s still a warming trend that would probably continue for hundreds of years.

It was determined that the worst impacts of global warming could probably be avoided if we could prevent global average temperatures rising by more than 2 degrees Celsius or 3 ½ degrees Fahrenheit.

And so a bunch of governments came up with this idea to agree to trying to prevent temperatures from rising more than 2 degrees. So this is kind of the new tack now.

Unfortunately, there’s no evidence that any policies being put in place can actually achieve this. And there’s some concern now from people like Jim Hansen, a somewhat controversial figure because he’s, you know, kind of crossed that line from scientist to activist. But he’s a smart guy with a lot of smart people working for him. He’s expressed concern of late that even if we were able to stop the temperature rise at 2 degrees, it wouldn’t be sufficient to avoid some of these severe outcomes.

BROOKS: Such as?

MILLER: Depends on where you are. In California, for example, the most I think significant impacts will be in terms of availability of water. I do think that the snow pack will shrink; the melt will come earlier in the spring. Run-off will occur sooner and in greater pulses. So we won’t get the nice even distribution from the so-called frozen reservoir that we’ve enjoyed in past years.

And there’s going to be problems with how to get the water where it’s needed when it’s needed. Most fire ecologists and climatologists, I think, agree that the severity of wildfires is going to be an issue.

But a big effect would be rising sea levels which, again, there’s a range of predictions of how much the sea will rise between now and, say, 2050 or the end of this century. But the planning parameter is 16 inches by 2050 and 55 inches by the end of the century, both of which are significant. And these estimates don’t seem to go down with the addition of more data. They seem to go up.

So much depends on how rapidly the polar ice melts. It’s hard to predict that. But a certain amount of sea level rise is due to simple thermal expansion. If you heat up a molecule of water, it gets bigger. And more severe weather events push those bigger molecules farther and farther inland during high tides and storm events.

So I think it’s clear there will be more coastal erosion than there has been in the past. And more inundation of low-lying coastal and Bay land areas.

BROOKS: Are the severe weather events such as the tornadoes we’ve been experiencing connected to climate change?

MILLER: In my opinion the thing that’s finally going to convince people that something is going on is severe weather. That might not be the biggest factor in California, but I think it’s going to be the biggest factor throughout most of the country and the world.

And by severe weather, I’m including things like prolonged severe droughts–if you look at what we recently saw in Texas, for example. I think already people are looking around and realizing that something is going on. And that’s why you’re starting to see the polling numbers move.

As far as the direct linkage between tornadoes and climate change, some severe weather events are more easily linked than others. The state of the science right now has made a pretty strong link between heavy precipitation events and global warming.

But with tornadoes, the last time we interviewed Jane Lubchenko, the head of NOAA, she was saying and I’ve since had that kind of reconfirmed that tornadoes actually are one thing that there isn’t a very clear link to.

But Hurricane Irene from 2011 may be a glimpse of the future. We’ve always measured hurricane strength by wind speed. And I think what we’re seeing is the new signature of hurricanes, which is not wind speed but precipitation. It’s the amount of sheer water in them. You know, as the oceans have warmed, there’s more water vapor in the atmosphere. And it’s waiting to fall out in these major storm events. And there were places along the hurricane path where they, along the track of that storm, which saw like a foot of rain in a day.

I think that’s a change that we’re going to be observing more and more. You know, in 2011 there were about a dozen weather-related disasters in the United States alone that cost more than $1 billion in damage. You can bet the insurance industry is taking a look at this. The insurance industry does not deny that the climate is changing. And doesn’t particularly deny the reasons why, either. And they’re paying close attention to this because it’s potentially going to be a huge cost for them.

BROOKS: So what’s the stumbling block to getting more people to believe this is real?

MILLER: Part of the problem is that scientists are notoriously poor communicators and they need to do better. Just recently I was watching Jane Lubchenko testify on Capitol Hill. And California Republican Dana Rohrabacher rolls out this GAO study where they had found that a large percentage of NOAA’s weather data stations around the country were in sub-optimal locations, and that might be affecting the quality of the data we’re getting from them. And she really didn’t have an answer for it. She gave a very poor answer when confronted with it.

There are substantial efforts underway right now inside organizations like the American Association for the Advancement of Science to train young scientists coming up, grad students, and the people who are going to be the scientific leaders of tomorrow, to be better communicators. Because they’re realizing how very important this is.



Category: Environment, Science

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  • Albertellul

    These AGW believers don’t even know their science. Here they use the ‘gravity’ analogy, saying that gravity is a theory same as the AGW thoery. Nonsense. Gravity is a physical LAW not a theory. The Law of Gravity, same as there are many other physical laws, such as the laws of thermodynamics, etc. But AGW is a theory which has failed completely to predict correctly todays global average temperature which should be much higher than it is if the computer models were right.

    Regardding the 97% of scientists who believe in a 90% chance of AGW being correct. This is all humbug. I am one of the many who, basing my opinion on scientific data and knowledge, have come to the informed conclusion that the modern global warming, (yes it has happened as it has hapened 5 times during the last 4500 years) is mostly natural due to solar/cosmic radiation and other forcings. Anthropogenic carbon dioxide gas is innocuous, it  is just 0.0012% of the total atmospheric gas composition, while natural CO2 is 0.04%.

    • Anonymous

      Invoking “solar/cosmic radiation” as the source of warming is just one of many false things you posted that proves you have a totally uninformed opinion.

      Go back to the website of college dropout Anthony Watts.