Dr. Pieter Tans of the Global Monitoring Division of NOAA told Thom about the spiking of carbon dioxide and methane levels in the atmosphere, global warming, and the possible consequences.
Thom Hartmann interview with Dr. Pieter Tans, January 26 2006
[Thom Hartmann] The place where smart people get their news. Speaking of smart people, Dr. Pieter Tans is with us. He's with the Global Monitoring Division of NOAA, the National Oceanic and Atmospheric Administration. Since 1985 he's lead the Carbon Cycle Greenhouse Gases Group at the Global Monitoring Division of NOAA's Earth System Research Laboratory in Boulder Colorado. This is the leading international programme measuring carbon dioxide and other greenhouse gases and forms the backbone of the Global Atmosphere Watch Programme of the World Meteorological Organization. Dr Tans, welcome to the programme.
[Pieter Tans] It's nice to be there.
[Thom Hartmann] Very glad to have you here with us. Dr. Tans, we have been reading in the papers here recently that carbon dioxide has been spiking more rapidly than we have seen in the past. We've passed several new critical thresholds. What does this mean?
[Pieter Tans] Well, I should start by saying that even though I work for NOAA, I'm not speaking for NOAA; I'm speaking for myself.
[Thom Hartmann] Right, OK.
[Pieter Tans] As a scientist.
[Thom Hartmann] All right.
[Pieter Tans] OK, having said that, yeah, the increase that we saw this last year, 2005, of carbon dioxide was one of the highest we've ever observed, so in that sense it's somewhat special. But in another sense it's not special, because the modern measurements of carbon dioxide directly done in the atmosphere started in 1958. That was done by David Keeling of the Scripps Institution of Oceanography and so we're now in our 48th year of that. Every single year, carbon dioxide has gone up. What we do see today is that, say, the five year average rate of CO2 increase is about three times as high as it was when these measurements were started in the late 50s and early 60s.
[Thom Hartmann] What does this mean?
[Pieter Tans] It's because we know for a fact that this increase is caused by the burning of coal or oil and natural gas and the rate of burning today is slightly over 7 billion tons of carbon per year that is somewhat, you could say that's equivalent to 7 cubic kilometers of stuff. Whereas in the late 50s, early 60s it was approximately 2 billion tons of carbon. So the rate of burning has gone up significantly, as has the rate of atmospheric CO2 increase.
[Thom Hartmann] Now, as the atmosphere...
[Pieter Tans] They go together.
[Thom Hartmann] Yeah, as the atmospheric CO2 goes up we're also seeing an increase in other greenhouse gases, methane for example.
[Pieter Tans] Yes.
[Thom Hartmann] Some people are suggesting that this is a consequence of global warming; thawing out old peat bogs and other sources of methane. Others point to industrial agriculture. What's your take on this?
[Pieter Tans] Yeah, methane is quite an effective greenhouse gas per molecule, but there's much less of it in the atmosphere.
[Thom Hartmann] Right.
[Pieter Tans] Now, methane has been going up also since pre-industrial times, since, say, 1850, by a factor of about two and a half, so that's quite a significant increase. We think that this is mostly due to things like rice agriculture, animal husbandry, like cows emit methane, for example. Wetlands have decreased, actually, in a lot of tropical areas, which might have decreased methane emissions somewhat. It also comes from fossil fuel exploration and exploitation. You know, when we pump up oil, for example. The gas that is often associated with these oil reservoirs used to be just flared into the atmosphere and lost. Now we capture it. So, it used to be a relatively large source; not so much any more. When we mine coal, for example, methane is liberated.
[Thom Hartmann] What about the thawing of the tundra, the permafrost, in Siberia and Alaska?
[Pieter Tans] I know. There is a possibility that as the tundra warms, that we create initially more wetlands and eventually we'll thaw out. As we create more wetlands, we may actually cause higher methane emissions.
[Thom Hartmann] Now we just...
[Pieter Tans] But I must say, we have a global observing network of these things. We don't see that. So, we don't see that the rate that methane at high northern latitudes is rising faster than elsewhere. In fact, for the last ten years, methane has stayed almost constant in the atmosphere. But that's not true for CO2. CO2 continues to go up.
[Thom Hartmann] Right. OK, well we only have about five minutes to wrap this up and I want to get to, kind of, you know, the punch line. I mean, what does this mean to all of us? We just saw Hurricane Katrina. We just saw the worst tornadoes in American history, at least for some of the regions that they hit. Weather is getting wilder, it seems; it's getting more unpredictable. Is this a consequence of this increase in carbon dioxide in the atmosphere, or could it be?
[Pieter Tans] I would say it's likely. You know, we cannot prove this without any reasonable doubt. What we can say is that the increased greenhouse gases, and CO2 in particular, do change the heat balance of the atmosphere, and currently CO2 alone has changed that by .7% of all solar observed radiation. That, you know, the climate is driven by the observed solar radiation; more in the tropics and relatively little at high latitudes. And that temperature difference generates winds and ocean currents; basically generates the climate that redistributes the excess heat from the tropics. It redistributes it partially to higher latitudes. That is the climate. Now, when we put these greenhouse gases in the atmosphere, we prevent some of the heat radiation that escapes normally from the Earth into space; it prevents it, heating up the lower part of the atmosphere more than it otherwise would.
[Thom Hartmann] Right.
[Pieter Tans] So we're changing the climate engine of the Earth,. That's something we know. There's no doubt about it. And we even know by how much.
[Thom Hartmann] So what will the consequence be of that for us humans?
[Pieter Tans] Yeah, that's, you know, that's actually is quite difficult to predict, what will happen exactly. What we... So we're intensifying the climate engine, if you will. But to make really credible predictions at this point about it will get wetter here, warmer there, a little cooler there, hurricanes will become more intense. These things are all likely, we cannot really prove it at this point.
[Thom Hartmann] Right, a couple of quick questions, then.
[Pieter Tans] Yeah.
[Thom Hartmann] So far, you know, up into this point, the atmosphere has been in relative equilibrium. It's been fairly stable for about 11,000 years I believe.
[Pieter Tans] Yeah.
[Thom Hartmann] And, relatively speaking, and there is some concern that we could flip into a positive feedback loop, where every change in the atmosphere that would normally trigger a corresponding negative change will instead trigger a corresponding positive change and create a spiral, and amplification spiral. For example, the carbon hydrates that are frozen below the surface of the sea could begin to melt and, you know, you have soda pop, you know, like, you know, opening a bottle of coca cola. All of a sudden the sea starts bubbling all this carbon dioxide into the atmosphere and methane cos there's millions, billions of tons of that stuff under there. That's number one. And number two, shutting down the Gulf Stream which brings heat to Europe, at least, to the western part of Europe.
[Pieter Tans] Yes.
[Thom Hartmann] And, you know, if that were to happen, then Western Europe is going to end up with a climate very much like Siberia. Are those things in the cards?
[Pieter Tans] I would say they're in the realm of plausible. But again...
[Thom Hartmann] Not just possible, but plausible.
[Pieter Tans] Yeah. I would say, the Gulf Stream will likely be affected by all this.
[Thom Hartmann] In our lifetimes?
[Pieter Tans] It may not be as we expect currently as climate models have their, you know, different climate models predict this slightly differently, each one of them. It may still be that we've overlooked something for our predictions, so I do expect the Gulf Stream to change, but not necessarily precisely as is predicted. Generally for these methane hydrates that you mention, that is potentially a trigger to huge climate change.
[Thom Hartmann] This would be like 'end of dinosaurs' kind of climate change.
[Pieter Tans] Yeah, that kind of climate change.
[Thom Hartmann] We're talking about, you know, now, when, during the last extinction, we saw something like 90% of life on Earth vanish. I mean, it was just a massive extinction.
[Pieter Tans] I tell you, something like this happened, actually, 55 million years ago. A huge addition of carbon dioxide to the atmosphere - ocean system happened at that time. And it was a very subtle spike, and it increased global temperatures by between five and ten degrees centigrade.
[Thom Hartmann] Dr. Tans, we have less than thirty seconds left. Have we reached a point of no return?
[Pieter Tans] That's the, I can't say that. I can say that we already have committed the Earth to significantly more warming than what we have already seen by the CO2 that has already been emitted. That's a fact. Because the Earth has not come to equilibrium with the CO2 that has already been emitted. So that's still to come. Then we are furthermore committed to, additionally, a very large additional amount of carbon dioxide emissions. Just because our industrial society depends on emitting CO2, on burning coal, etc., and therefore emitting CO2, basically giving us the energy that we need to function. This doesn't, this we cannot change in a couple decades. It takes a long time to reform energy systems.
[Thom Hartmann] Sobering news. Dr. Pieter Tans, with the Global Monitoring Division of NOAA, speaking for himself. Dr. Tans, thank you so much for being with us.
[Pieter Tans] OK, thanks.
[Thom Hartmann] And for more information, www.cmdl.noaa.gov the web site.
