The only thing we can be sure of about the future is that it will be absolutely fantastic. So if what I say now seems to you to be very reasonable, then I have failed completely. Only if what I tell you appears absolutely unbelievable, have we any chance of visualizing the future as it really will happen.

- Arthur C. Clarke (h/t Brin)

Saturday, August 14, 2010

The Name of the Problem

Honest to God, they think we're happy about this.

And much as I'm both exhausted and all wound up tonight, I have to say what I think is going on. I think it's starting to really hit the fan. That is really really bad. It's way too early.

WE DIDN'T KNOW WHEN IT WAS GOING TO HIT THE FAN

But I'm very sad and worried that we might know now.

WE MIGHT KNOW NOW

See there are a bunch of questions. Let's do a Q and A. I'll ask the questions in the right order, and then I'll answer them. See if things come a little clearer as a result, and let me know.



HOW MUCH OF THE CARBON STAYS IN THE AIR?

First, despite odd year-to-year variability on WHERE the carbon seems to be going, the amount that stays in the atmosphere seems a relatively constant fraction. For big picture approximation, a half is just fine, though some argue it might slip to three quarters.

HALF THE CARBON WE EMIT STAYS IN THE AIR PRETTY MUCH PERMANENTLY ON POLICY TIMESCALES.



WHY DOES THAT MATTER?
I think everybody agrees that until the Great Bush Economic Glitch, (and let's call it by such a name, please) this amount was increasing rapidly, and there is enormous pressure, especially in China and the US, to get this back on track. Anyway, the amount we dig up out of the ground and spew isn't going down much. And because carbon doesn't really go away on the time scale of human lifetimes, the amount in the atmosphere keeps growing, and roughly speaking, will keep growing until we stop emitting carbon altogether.

CARBON ACCUMULATES



SO IS THAT ACCUMULATING, LIKE, ALOT?
"A lot". Two words, there, dude. Pet peeve. You get allotments, I get allitlements, and you end up allotted with a lot. Anyway...

Carbon accumulates, as do other greenhouse gases, but let's assume we can at least get a grip on those. But those others make matters worse. Either way the upshot of what ALL the economists tell us is that if we work really hard, we can, if we try really hard, limit the damage at the point where we get just shy of a doubling of preindustrial CO2, if you count all the other greenhouse gases as if they were CO2.

ACCUMULATING CARBON DIOXIDE AND OTHER GREENHOUSE GASES ADDED IN AS EQUIVALENT CARBON DIOXIDE IN THE ATMOSPHERE WILL AT THE VERY LEAST BE ALMOST THE EQUIVALENT OF DOUBLE PREINDUSTRIAL CONCENTRATIONS. (WHICH IN TURN WERE QUITE HIGH COMPARED TO THE MOST RECENT 3 MILLION YEARS. SO THE EARTH IS AT LEAST TEMPORARILY ENTERING A RADIATIVE REGIME WHICH IS LITERALLY WITHOUT PRECEDENT.)



UM, WITHOUT PRECEDENT? SO MEANS THATS GONNA WARM US UP AL... ER, A GREAT DEAL, RIGHT?

No, hang on. I knew we were gonna jump the gun on this "global warming" thing,

So there's a lot of attention to Global Mean Surface Temperature. A lot of it is greatly overvalued. I think this is because of the dreadful misnomer "Global Warming".

Yes, we are warming but that isn't really the point. That's inside baseball. The thing that the general public should understand is we are monkeying with the whole climate, not just the temperature.

The globe, which is to say, the surface of the earth, is indeed warming, and that is indeed as a result of greenhouse gas accumulations (and somewhat counterweighed by dust form pollution).

But the cartoon version, that it is a direct result, leaves a lot out. We hear people saying that "global warming is gonna cause HUUGE CHANGES in the weather" but that is causally all screwed up when you really look at it. Aerosols change the pattern of incoming energy, and greenhouse gases change the pattern of outgoing energy, and the land surface is also changing more and more rapidly in various places. We are kicking around the only home we have in the universe as if it were an old tin can. One of the things that happens when you kick this can in this way, we are pretty sure, is warming. But the can never warms that much without a whole lot of other crazy stuff going down. You don't just hold a match to it. You change where the energy comes in and where it goes out. The whole engine of climate is to move the energy from where it comes in to where it goes out and we are changing THAT.

THE HUGE CHANGES WE ARE MAKING IN THE CLIMATE ARE GOING TO CAUSE GLOBAL WARMING


SO WHY DOES EVERYBODY TALK ABOUT GLOBAL WARMING ALL THE TIME? I MEAN IF IT'S JUST A CONSEQUENCE?

There are a bunch of reasons, some good ones and some really terrible ones. A lot of confusion comes from the fact that people insist on calling the problem "global warming" and not "climate change". In fact, just to make things clear, I'm not going to say "global warming" again after this paragraph. The words "global warming" confuse and obscure. If I'm going to talk about the surface of the earth warming on average, I'll talk about increasing Global Mean Surface Temperature or "increasing GMST" or if I'm feeling particularly geeky, "++GMST".

But it's also the fact that, left to its own devices, the global mean surface temperature is extremely stable. One place may have a cold year and another place may have a warm year, but the world pretty much stays the same temperature. Now that is only relatively recent. It's only been like that for ten thousand years. But if humans hadn't come along, the signs are the happy animals would be having a long break before the next ice age would kick in. Because the ice sheets have settled down, because the orbital forcing is in a very moderate part of the cycle, and because the sun is calm and stable these days, and because there haven't been any asteroids or supervolcanoes, the climate was able to settle down. And once it settled down, its temperature became almost solid as rock, like Uncle Sam's pulse, constant, unvarying. The energy was coming in and going out at the same rate, year after year, decade after decade, century after century. The ocean sloshed around enough to move mild hot spots from one place to another on longish time scales, but the average seems to have been very steady.

So things have stayed the same until pretty much the last few decades, but they're starting to drift. Pretty much in exactly the way that was predicted by a conclave of the world's best meteorologists and oceanographers in 1979.

So if things start to drift, it isn't because the climate fairy went around the world giving an extra 0.7 degrees C to every town and village and keeping the weather the same. It's because the weather is changing that the system can find a new temperature. Climate change causes increasing GMST, not the other way around. So one of the reasons we study GMST is because it gives us a measure of how much the climate is changing.

Think of taking the planet's temperature as being, like, seeing how bad a fever the earth has.

INCREASING GMST IS A MEASURE OF CLIMATE CHANGE

SO HOW MUCH CHANGE IN TEMPERATURE IS BAD?
LET ME GET BACK TO THIS ONE, AFTER WE TALK ABOUT HOW MUCH WARNING WE'RE GOING TO GET


SIGH. SO HOW MUCH IS IT GOING TO WARM UP THEN?
THE QUESTION HAS TWO PARTS. THE FIRST PART IS WHAT THE SENSITIVITY IS.


UM, DID YOU JUST CHANGE THE SUBJECT? SENSITIVITY? LIKE, CHICK FLICKS?
Climate sensitivity. Actually, that has a bunch of meanings, and I suspect that's why Lindzen and Spencer keep managing to get the answer they want. What we usually mean is, what's the number that connects CO2 radiative forcing to temperature change.

Now for various technical reasons, it's usually stated as equilibrium change in GMST per CO2 doubling. There are reasons to expect that that number is roughly the same, no matter where you start the doubling from, over a broad enough range to cover what humans could ever possibly do.

And we think we have a good grip on this number. It's probably between 2.5 C and 3.0 C per doubling, pretty much certainly between 1.5 and 5 C.

Now this number does sweep under the rug the problem that we may jostle the system enough to inadvertently release natural carbon too. Methane deposits are especially scary because there is a lot of methane, it causes a lot of greenhouse effect, and when it finally breaks down its carbon ends up as CO2 anyway, to plague us approximately forever. Fortunately, this looks not to be fast enough of a process to change the picture too drastically. That's not a lock, though. Let's hope it holds up.

SO IF CO2 DOUBLES, WE'RE LOOKING AT A WARMING OF AROUND 2.5 C, GIVE OR TAKE



SO IS IT GONNA DOUBLE? QUADRUPLE? WHAT?

A couple of years ago, it looked like we would run out of fossil fuels pretty soon, but there's been a huge burst of invention. There are various deposits around the world that nobody would have dreamed of touching a few years back that are now online and producing at scale, notably tar sands and nonporous rocks. So at this point it's hard to come up with a constraint on natural gas or coal, though petroleum itself is getting harder to find. Now some people think that is a showstopper, but I don't see it. It will drive up the price of gasoline, so electric cars and trains will replace cars and trucks. The question is mostly where we get our electricity.

And basically, between the day we decide to take this problem seriously, and the day it stops getting worse, there's probably about forty years.

Deciding to take the problem seriously mostly has costs immediately and benefits decades in the future. This is why it is an ethical problem. And it gets more and more expensive to deal with the longer action is delayed. The increase in technological prowess will have a very hard time even keeping up with the increasing population, increasing demand, increasing dirtiness of the remaining fossil fuels, and increasing climate impacts on aggregate wealth. Those who insist we delay while progress gets us further are asking us to bet the farm on an inside straight.

So, we could be looking at anywhere from double to eight times CO2 by the time all is said and done. Maybe more but nobody even has the remotest idea of what life would be like at 16xCO2. The good news, I suppose, is it would promote space travel.

WE COULD BURN ENOUGH CARBON TO PROMOTE SPACE TRAVEL


SPACE TRAVEL???
WELL, THERE'D BE NO PARTICULAR ADVANTAGE TO STAYING ON THE SURFACE OF THE EARTH, REALLY. IT'S SPACESUITS OR NOTHING AT THAT POINT.


SERIOUSLY?
I DON'T KNOW. BUT IF WE DON'T TAKE THIS ON NOW, WHEN WILL WE? NOT WHEN WE'RE RUNNING AROUND IN SPACESUITS, I'LL WAGER.


OK, BUT HOW ABOUT BY THE YEAR 2100?
THE BETTING IS, IF WE TAKE WHAT IS CALLED "NO ACTION", MEANING WE KEEP MONKEYING WITH THE SYSTEM FOR INDIVIDUAL GAIN AND NO REGARD FOR MUTUAL LOSS, ABOUT 3 OR 4 C INCREASE IN GMST AND STILL RISING IN 2100; SOME SAY EVEN MORE.



SO HOW BAD DOES THAT SUCK?
Well, now we come to the hard question. How much suckage comes with each degree.

Mark Lynas wrote a relatively alarmist book about that, and there has been some TV made around the book. It's plausible. But we are somewhat out of the physical sciences and into economics and biology with that question. The science of ice sheets, while quite physical, has no precedents to base its predictions on. So to some extent we're guessing.

We haven't talked about climate simulation models yet. The thing about climate models is that they have to be tuned to present day conditions to be useful as simulations. The more phenomena you add, the harder that is in principle. So the models have always had kind of a stodginess to them; one of their worst they do not deliver extreme events at the rate and extent that the real system does. And one of the biggest questions we have to ask is about extreme events. Eventually, it is possible that reality will be too far afield from where the models are tuned, and the models will get much further from reality than they are in present and recent past simulations. One of the ways they may fail is in telling us about extreme events.

Now there are lots of theoretical reasons to expect more extreme events. And lots of reasons to expect the models can't predict them well. At some point, it is plausible that the models will simply not represent some of the phenomena that the system actually gets.

AT SOME LEVEL OF CLIMATE CHANGE MODELS LOOK LIKELY TO FAIL TO TRACK THE GENERAL WEIRDNESS LEVEL


SO?
So we don't know if or when that time will arrive. We know climate will change, but in what ways, with what consequences. In other words, we don't know at what temperature the changed climate really starts to bite. This has allowed us to delay policy, after all a change of 0.7 C locally is barely even measurable, never mind noticeable. How could it possibly matter as a change in GMST?

WE DON'T KNOW AT WHAT GMST LEVEL THE WEATHER CONSEQUENCES OF CLIMATE KICK IN. OR...

OR...?
OR AT LEAST WE DIDN'T UNTIL RECENTLY


HUH?
WELL, IT APPEARS AS IF IT MAY BE HITTING THE FAN ALREADY


YIKES! DO TELL!
IT'LL HAVE TO WAIT FOR ANOTHER DAY


Anyway, that's what I think

As one takeaway, names are important. Let's call increasing GMST "increasing GMST" and anthropogenic climate change "climate change" please, or we will continue to get horribly confused by calling just about everything "global warming".

And let's call the Bush Recession by its name too.

Thanks ever so much.


Update: Woot! Moranoed on account of the spacesuits bit.

Welcome, folks, please come back for the planned sequel...

Update: The sequel is here.

24 comments:

Steve Bloom said...

Nitpick: Except the change in atmospheric T is the direct consequence of the change in forcing, and the other consequences flow from it (other than direct local effects of land use change, and I suppose the direct surface warming effect of soot, but these aren't the main thing going on.) Saying that climate change results in warming doen't seem quite right

Oale said...

Acid is acidic, be it carbonic or sulfuric. Adding either to an aquarium isn't a good idea for keeping the fish healthy.

Marion Delgado said...

I could find a bizarre Byzantine pathway by which we'd be happy about this. If the Credibility Fairy shined on us suddenly because we were so right, so early, then yeah, maybe the calamity of it all would at least take the main causal trigger out of the mix. But that's not happening. We're getting an ounce more credibility for every pound of catastrophe.

But of course, they'd REALLY not believe me if I said environmentalists would rather be dealing with anything but climate change. climate scientists probably are, in general, getting a little cachet out of it.

If a meteor was going to hit the Earth, astronomers, astronauts and other techs would get a little cachet out of that.

Michael Tobis said...

Steve, no, that is not a nitpick, and it really is what I'm saying.

The usual picture that is painted of the greenhouse effect is valid in the global mean, but locally, it is a small term compared to import and export of energy from neighboring areas. We are talking about a small change in temperature spread out over years. If it were really just a local phenomenon, we would not expect much effect on weather. And that seems to be how everybody is thinking of it.

It's not really wrong, but I think it risks missing a key point. The parts of the earth where energy comes in (on account of aerosol forcing), and the parts where it goes out (on account of greenhouse forcing) are changing on a very broad scale. The whole job of the weather engine changes. Consequently the weather changes.

Lindzen thinks clouds will contrive to keep warming down. I've seen someone suggest that melting ice will keep warming down, and that indeed that is what we are seeing. Warmoing the deep ocean can keep temperature down. Temperature change is likely, but it isn't 100% guaranteed. Climate change is nevertheless guaranteed under present circumstances. So the usual causation argument is, misleading.

So one way of looking at it is to say yes, the global forcing is the aggregate of the local forcings, but the global response is NOT a simple aggregate of the local responses. Local forcings are not evenly distributed any more than the local baseline is. ANd that forces the fluid flow in new ways.

So eventually we expect to see new large scale flows. And that's why this summer is scary.

Pico said...

Michael, do you know if any of the climate models exhibit weather patterns like this year's northern weirdness or the last years Australian horror? And do any of them have monumental shifts in ocean currents. Do they suggest that the climate system is likely to snap into new configurations or will it start chaotically flipping between configurations. In other words do the models suggest that we will see this and last year's climactic events being repeated to greater and lesser extents or similar such at least, or is there a possibility that will we see completely novel and unforeseeable weirdness happening ever more often? Is anyone looking at this?

Nick Barnes said...

I think the constant "airborne fraction" of 1/2 is pretty well understood to be a neat coincidence between exponential emissions growth and concentration-driven growth in absorbtion by the oceans (and some second-order terms). If emissions suddenly doubled, the airborne fraction would become 3/4. If emissions suddenly halved, the airborne fraction would become zero.

Search stoat for discussion of this.

Michael Tobis said...
This comment has been removed by the author.
Michael Tobis said...

Pico, my understanding is that climate simulation models do not produce enough large-scale anomalies in even baseline climate. So they may not be a good tool for this purpose.

I will try to explain why that is exactly what I myself have been expecting. But I was not expecting it YET. I do not know how commonly this expectation is held.

I will say that it is not clear how to investigate it, and that the models are not very helpful in this regard, because they are intrinsically conservative.

Tom said...

And this is why your team has been getting in trouble for, what--five years now?

On this blog you say 2.5. On Collide-a-Scape you say 160 degrees F. While you gloat over the image of my 'cowering in a tiny, massively air-conditioned room.'

You can't keep your falsehoods and exaggerations in order. So you get caught.

Michael Tobis said...

Tom confuses a reductio ad absurdum argument with a prediction.

Kooiti MASUDA said...

Some personal thoughts about the term "global warming".

I think I understand what MT says, and I agree on the principle. Anthoropogenic climate change makes impacts not through the global mean temperature.

But, regrettably, it is difficult for me to follow the suggestion.

It is partially because of the situation of the Japanese-speaking world (plus my desire to keep direct correspondence between English and Japanese in scientific terms). The Japanese equivalent of "climate change" has too much connotation of natural variability, and "anthropogenic climate change" is too long. So I resort to the equivalent of "global warming". I do often emphasize that global warming is not just increase of GMST but something much more complex.

Another cause is my personal history. I became interested in climate through learning about glacial cycles. Also, according to Weart's "Discovery of Global Warming" (as I understand), understanding of glacial cycles seems to have been the largest motive of the development of the science of climate change before 1970s. When the term "climate change" is used without qualification, it always reminds me the issue of glacial cycles in addition to the anthropogenic one.

The exit seems to be making some shorthand of "anthropogenic climate change" popular. I do not think "ACC" likely, for it means Antarctic Circumpolar Current to many climate scientists. I will try to estabilish a Japanese version, but it seems to be a long way.

PDA from Let's Get Small said...

Tom, caught in what? The 160° bit was an exaggeration to make a point in comment on a blog, not a scientific paper. Did you really not get what MT meant when he wrote "at some point you get enough weather that it is climate?"

Where your "team" gets in trouble is taking remarks out of context and brandishing them with a smug "Gotcha!" I have no doubt that you'll still be yelling "MT predicted 160°" well into the 2020s.

Anyway, on the semantics thing, I've long preferred the term "climate chaos" to "climate change." I think it better captures the consequences: not merely change to a somewhat different but stable regime, but to an unknown and likely unknowable future. Either way, though, I agree that just talking about "warming" is unhelpful.

Michael Tobis said...

The trouble with "climate chaos" is that the word "chaos" has a technical meaning in fluid dynamics that has nothing at all to do with how out of the ordinary an event is. It just replaces one confusion with another.

I am OK with "climate disruption".

Notechaser said...

Shouldn't that be GMST++? (Although it does sound like an odd time-zone mashing, either way.)

--Melting in Oregon

Richard Reiss said...

Moscow --

http://www.nytimes.com/2010/08/15/opinion/15pavlova.html

Hank Roberts said...

Scholar turns this up:
http://www.springerlink.com/content/t373146071225m31/
Climate Dynamics
DOI: 0.1007/s00382-010-0776-4
Changes in storm tracks and energy transports in a warmer climate simulated by the GFDL CM2.1 model

"... Recent studies have indicated a poleward shift of the storm tracks and the midlatitude precipitation zone in the warming world that will lead to subtropical drying and higher latitude moistening. This study agrees with this key feature for not only the annual mean but also different seasons and for the zonal mean as well as horizontal structures based on the analysis of Geophysical Fluid Dynamics Laboratory (GFDL) CM2.1 model simulations. Further analyses show that the meridional sensible and latent heat fluxes associated with the storm tracks shift poleward and intensify in both boreal summer and winter in the late twenty-first century (years 2081–2100) relative to the latter half of the twentieth century (years 1961–2000)...."

Related papers on that page include:

http://www.springerlink.com/content/358xr26386767783/
Representation of Northern Hemisphere winter storm tracks in climate models
C. Z. Greeves, V. D. Pope, R. A. Stratton and G. M. Martin
Climate Dynamics, 2007, Volume 28, Numbers 7-8, Pages 683-702

Cited by:

http://scholar.google.com/scholar?cluster=9173339422441407063&hl=en&as_sdt=2000&as_ylo=2010

EliRabett said...

Tom, would you settle for 159 F?

(of course that is out in the open in a desert)

DavidP said...

Well expressed and convincing.

I've decided that the world needs nuclear power to be made less costly than coal (by solving problems, mass production, resolving politics) - it seems to be the only globally applicable way to stop emitting vast amounts of C02 for electricity generation.

I just don't think that most country's leaderships are capable of responding appropriately to Global Climate Change without cheaper-than-coal nuclear power. We'll have to find ways of managing the problems of nuclear power or surrender to ever worse Global Climate Change.

Marco said...

DavidP:
define "cheaper"?
Nuclear power is already "cheaper" per kW. It's the initial investment that is causing most trouble. A x-billion nuclear plant versus a x-million coal plant. Common problem all around. We'd have to reduce the initial investment by a factor 10 at least, but how?

Aaron said...

Models of ice dynamics inherently have similar issues as global climate models, and thus are not likely to accurately predict ice sheet movement prior to its occurrence. In particular, ice models are not likely to predict progressive structural collapse of ice sheets until after the modelers have actually seen a few ice fields undergo progressive structural collapse. Thus, sea level rise events are not likely to be predictable except as we predict earthquakes, “big one coming in next 30 years.”

However, the time element of earthquake forecasts is based on historical earthquake records that we do not have for ice movements. Thus, the first few ice dynamics event forecasts by reputable forecasters are likely to be limited to, “big one coming.”

I am NOT reputable, but I can say that, about ice sheet movement and sea level rise, “Big One Coming!”

There really is no need to wait for better ice dynamics models before we start aggressive planning for sea level rise. And, while we are at it, we need to get out of the river flood plains also.

When the phrase “6-sigma” came into vogue, a million dollars was a lot money and a million people was a lot of people to be affected by anything. Now, we talk in terms of billions of dollars, tens of millions of people, and we are starting to see 6-sigma weather, before the Arctic sea ice is gone. We need to plan for 9-sigma weather.

Steve Easterbrook said...

I'm all for "Climate Disruption". It's certainly the most accurate term out of all the ones suggested so far.

With respect to the models, they are designed almost exclusively to simulate (and hence understand) climate processes experienced in the near past (typically the 20th century, although past millenium is getting some attention now too).

Paleontology studies shows that earth systems are twitchy, but we can't predict the thresholds that lead to new climactic states, because if a model simulates such a threshold, we have no way of validating it. Of course, once we've hit a few such thresholds, it will keep the modelers very busy incorporating the data into their models. But we really shouldn't be doing this experiment.

(Anyway, I really just stopped by to say how much I like the style of this post)

David B. Benson said...

Nick Barnes --- If CO2 emissions suddenly halved, the oceans would continue to equilibriate. Working this out is too hard for me because it involves carbonate buffering. Except for that, CO2 would continue to be absobed until equilibrium is reached.

David B. Benson said...

One vote for anthropogenic climate disruption.

Anna Haynes said...

MT, any chance you could add an anchor, at the "sensitivity" Q of the dialog?
(I want to link directly to it)