Thursday, January 27, 2011

The Earth's energy budget: A slow-motion climate catastrophe

John Farley writes (gotta teach that guy how to do it hisself):

The Earth's climate is warming at about 0.2 degrees C per decade. The average increase from one year to the next is only 0.02 C. At first glance, it seems incredibly small. Far too small to make a difference, let alone a disaster. How can such a tiny annual increase mean anything at all?

Here's an analogy: suppose that you eat 1% more calories than you burn up. That's 20 additional calories per day, more than your maintenance diet. Twenty calories is about two teaspoons of food. At the end of one year, you will have gained two pounds. That's pretty negligible for health effects.

Continuing at this rate, after 5 years, you will have gained 10 pounds. That's definitely enough to notice. After 10 years, you will have gained 20 pounds. And after 20 years, you have gained 40 pounds. At that point, you have gained enough
weight to affect your health. And after 30 years, you have gained 60 pounds, and after 50 years, you have gained 100 pounds. At this point, try to get yourself booked to appear on the Oprah Winfrey show.

The increase in global temperature is like that: the year to year increase has a negligible impact. But as the temperature rise accumulates relentlessly over decades, it makes a big difference. The energy imbalance is only 1-2 W/m2 out of the average solar power of 240 W/m2 (averaged over the Earth's surface). The imbalance in power is only about a half percent to one percent. But a persistent power imbalance results in a steadily rising temperature.

From one year to the next, the effect is small. But over a period of 50 years, it has big effects. This can result in problems in trying to convince the government to take action now. Consider the experience of Prof. Henry Abarbanel, a member of the JASONs, an elite scientific group that gives scientific advice to the government, mostly on military matters. The JASONs studied global warming. Naomi Oreskes, a science historian, interviewed Abarbanel, and asked him how the government reacted when told that in 50 years global warming would have a big effect on the entire earth. He replied, "they told me to come back in 49 years".[1]
Of course, at that point it will be too late.

[1] Naomi Oreskes and Erik Conway, Merchants of Doubt, Bloomsbury, 2010.


Anonymous said...

The point is sound, but the analogy is too flawed to be useful. There are feedback mechanisms in human physiology that maintain homeostatsis ( that's the difference between a living organism and an unloving physical system ) making it harder to gain weight than the example suggests (to make a very long story short, weight has a set point that tend to drift upward as we age, like blood pressure). Also, and sadly, you have to be a lot more than a hundred pounds overweight to be noticed in America these days.

I think a better biological analogy for AGW is cigarette smoking. Things go great at first. You lose a couple pounds, you get extra break time at work. Some people don't even believe smoking will do them any harm.

Then over time, there's gradual damage to your pulmonary and cardiovascular systems. It gets slowly and predictably worse. You still may think you can adapt to it -- take the stairs, skip the pick-up football game -- or at least that the problems it causes are less than the pain of quitting. So you go on smoking, thinking you are aware of the consequences.

Then, in a little while or a long while, depending on your level or smoking and your other habits but mostly on simple genetic luck, big, unpredictable, discontinous things begin to happen. You get pneumonia. You get a blood clot in your lung. You have a heart attack. It costs you a mountain of money and a lot of hard, painful recovery, but you make it through. Then maybe you quit (or maybe you're already dead).

But by then, you've been smoking for many years, and quiting, while helpful, will not give you back the heart and lungs you had. And so many, depending on habits and luck, will enter the final stage -- the discontinous thing that no amount of money or rehab will bring you back from. Inoperable cancer. Pulmonary hypertension. Severe congestive heart failure. Another heart attack. Debilitated, in agony, stripped of dignity and hope, you die in the ICU surrounded by machines. Not because you thought smoking was harmless. Because you convinced yourself that the small deposit of trouble you paid out of pocket at the beginning was or could be the whole bill.

-- The Tracker

Anonymous said...

Unliving, not unloving. Damn you, autocorrect!

Anonymous said...

Yes but add back in the weather and you do get nasty sudden increases. Ask the Pakistanis if 2010 was much different to 2009. Ask the same question of the Russians.

But then put on weight gradually and you hardly notice. Until the heart attack. So maybe the analogy is better than I first thought.

1998 was an extreme outlier, what will the next extreme outlier look like.

Little Mouse

Horatio Algeranon said...

There is just one problem with the weight analogy:

It may require determination and a certain amount of "discomfort", but one can lose weight -- even after gaining a lot of it.

Losing heat -- which requires losing CO2 -- from the climate system is much much harder.

It is a very under-appreciated fact that we (or more precisely, future generations) are going to be "stuck" with the impacts of increased atmospheric CO2 for a very very (very) long time -- even if humanity manages eventually to stop emissions entirely.

Many people seem to have the philosophy that there is a "fix" for everything so we need worry about things only after they happen.

This is undoubtedly one of the reasons why people have such a lackadaisical (hostile?) attitude toward the whole climate change issue -- that and the fact that they can't see how the outcome will impact them personally but they can see how the remedy will.

John Mashey said...

The cigarette analogy is better than the weight case, but can be made even clearer.
Let us recall that most smokers started when they were 12-18, because starting then "sets" the addiction during brain development. That's how the cigarette companies get lifelong (well, lifeshorter) customers, because it is very hard to stop if you start early.

To some extent, obesity or smoking are inherited by behavior, although some smoking parents are unable to quit, but determined their kids never start.

But a realistic analogy is:

1) Every year, some number of cigarettes are smoked worldwide, some of the smoke ends up in trees (who like it), some ends up in oceans (unliked). The rest builds up in the atmosphere.

2) People vary hugely in their smoking rates.

3) People vary hugely in the effects they see, so that some heavy smokers see no short-term effects, and in fact, actually get paid to smoke.

4) The effects if smoke level in year N are mostly delayed for decades.

5) When born, children start with the health conditions of their parents at that time, whether the parents smoke much or not.

6) Children are typically born with addiction levels similar to parents, and actually smoking more correlates with being richer, in short term.

7) People research tobacco-engineering to draw the smoke down worldwide with the idea

Anonymous said...

Or how about gradually injecting gazillions of toxic mortgages into the U.S. financial system? Oh, I forgot ... thank heavens the Republicans have pointed out that that was an unpreventable act of God. Good thing they had all those financial "fixes" all ready to spring into action, so that once the problem appeared, we could quickly prevent massive economic damage, loss of retirement savings, sky-high unemployment, collapse of businesses, etc.! Oh, wait ... that was in that other alternate history universe - my bad. In that light, is there any reason to expect a different outcome with AGW? After all it's an even more gradual process, and the initial bad outcomes are "just weather".
L Carey

Anonymous said...

It's kinda depressing that these seemingly remedial-level points have to be made, but as John Sterman (and others) have shown, simple stock/flow dynamics still seem to escape most of the population. So this case needs to made simply and repetitively, and I think analogies are probably the best tool.

That said, in my own efforts at analogies, I've had the same problem with the "weight gain" metaphor that Horatio has: The analogy tends to break down because it is so much more difficult to reverse the carbon flow imbalance than it is for calories. I'm still trying to come up with better "day-to-day" examples, but we need to reinforce these kinds of simple messages often... More please.


Robert I Ellison said...

Imagine, just for a moment, a world that doesn't warm for a decade or three - and what the political implications of that would be?

There is just such a suggestion of climate uncertainty as a result of what the Royal Society, in their recent climate science summary, called internal climate variation. It is irrelevant to the separate risk from greenhouse gases but very relevant to climate change politics. This suggestion emerges from peer reviewed science and must objectively be accepted as a very real potential that is likely to create a very real quandary for carbon reduction politics.

We need to go beyond the conventional ways of thinking about climate and adapt to uncertainty. Thinking on climate should be through the prism of chaos theory. The language should be in terms of climate change and climate risk, of internal climate variability and the implications of that, rather than a simple global warming in which the outcome is predictable with some certainty and within limits.


bill said...

So, what the various commenters are seemingly saying is, all analogies break down under examination? Including, surely, their own preferred alternative? Therefore, surely, the utility of any analogy is best judged by whether it's something people are likely to grasp at the gut (no pun intended) level?

Anonymous said...

A good analogy is gut-grasping while conveying, as far as possible, the truth of the thing described. Rhetoric is not an exact science, but there are still problems requiring the testing of various solutions. TT

Pinko Punko said...

How about a cumulative nerve toxin that builds up on your brain? Slow acting poison. Virus with latency period. vCJD.

Anna Haynes said...

See: The Micawber Principle.

"Annual income, 20 pounds; annual expenditure, 19 pounds; result happiness. Annual income, 20 pounds; annual expenditure, 21 pounds; result misery." - Mr. Micawber, penned by Mr. Dickens, recounted by Mr. Tobias

Anna said...

(Actually, according to Wikipedia, the Micawber Principle is "let's not put a price on carbon" techno-optimism.)

Hank Roberts said...

> tallbloke
> "... quantify the ether drift on Earth’s surface....
> confirmed by the determination much later of the
> velocity of the sun through space...."

So why haven't they discovered etheric frictional warming as an alternative source of heating yet? I mean, isn't it obvious?