Found this fragment, introductory to a talk. Probably nothing new to you. But this is roughly how I start out talks to the general public.
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I have no clear memory of first becoming concerned about climate change.
As a young science buff, the idea that that temperature of the earth depends crucially on the concentrations of a few trace gases, especially water vapor and CO2, was presented to me as uncontroversial, established fact by sources I trusted, notably Isaac Asimov, long before it made the news. The idea that this would present a problem in my own lifetime was not presented as controversial in the 1960s and I don't remember having any doubt about it as a young reader.
LBJ mentioned it in an address to congress in 1965, before my ninth birthday. Johnson's panel of science advisors told him
"By the year 2000 there will be about 25 percent more CO2 in the atmosphere than at present. This will modify the heat balance of the atmosphere to such an extent that marked changes in climate, not controllable through local or even national efforts, could occur."
In fact, this general picture was first known in the scientific literature by 1898.
I became professionally involved in climate in 1989. It interested me for two reasons. First, the climate system itself is a fascinating, intricate complexity with some rather beautiful mathematics associated with efforts to understand it. Second, it is a crucial example of how democracy is going to be challenged in the increasingly complex, increasingly tightly coupled world of the future.
Some non-obvious ideas had to be absorbed into the governing strategy by way of a democratic process. How would we cope?
So far, that question remains unanswered.
STARTING POINTS
Let me make sure you understand a four key points. These are points about which I am essentially certain, and which the public doesn't seem to understand, and which I think any sane discussion of our quandary has to start with.
1) It's already happening
2) It's cumulative
3) You ain't seen nothin' yet
4) Uncertainty is not our friend
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1) It's already happening
This is the main thrust of the third National Climate Assessment and the associated publicity push that put climate in the news this week. There's nothing particularly new in the report from a scientific point of view, but it's daunting. Everywhere you go, wildlife is stressed, infrastructure has taken some hits, agriculture is rapidly changing. We had our 2011 drought and fire season; New York City had its storm surge from Sandy; Nashville and Boulder and just recently Pensacola had unprecedented 24-hour rainfalls, and so on.
2) It's cumulative
The changes we are seeing are predominantly because of human changes to the natural environment, and of these, the most important is release of CO2 into the atmosphere. ANd CO2 is the most troubling for a couple of reasons. The first reason is that it's cumulative, CO2 is the product of ordinary combustion; we "light fire" to things and they release energy and turn into, basically, ash and steam and CO2. The steam rains out pretty quickly, but the CO2 stays in the air and the oceans for a very long time - thousands of years to make a dent in it, hundreds of thousands to fade away entirely.
This means that to stop climate disruption, that is the human-forced unnaturally rapid climate change, we can't just cut back on CO2 emissions. They basically have to stop altogether.
3) You ain't seen nothin' yet
The second reason its' troubling is that the system doesn't respond immediately. The air temperature changes more or less immediately (warmer near the surface, colder in the stratosphere, as the atmosphere acts like a better blanket) but it also responds to the ocean temperature and the ice temperature, and those change very slowly. So at any time we've only seen the effects of the CO2 we put out some years ago. Further, the economic commitment, our power plants, our roads, our vehicles, can't be turned around overnight. So by the time climate change is actually visible, you are already committed to a pretty severe
4) Uncertainty is not our friend
The doubts you hear so much about nowadays were not expressed decades ago, even though our scientific basis was much sketchier. The explanation has to be that decision points were further in the future. But the form of those doubts follows an old pattern of industry faced with inconvenient evidence - the casting of doubt. If there is doubt that cigarettes kill, or leaded gas kills, then surely it is unfair to penalize existing industries until the case is made, goes the argument. And to be fair, false accusations can be and occasionally are hurled at industry for a number of reasons. But the argument that we aren't sure in this case is irrational. We can't calibrate exactly how bad it's going to get by when, even if we could predict exactly how humans would act regarding climate-relevant behaviours. There are a number of climate-science uncertainties, and the purveyors of confusion are happy to dwell on them. But almost every one of these cuts both ways. The problem could be smaller and slower than we expect, but it could also be harsher and faster than we expect. So now the problem is actuarial. You protect yourself against the plausible disasters. You don't tell your child to cross the street in the middle of the block because chances are 99% that she'll get across in one piece! You worry about that hundredth time! Your child is precious to you, of course, but the world is precious to her! If you are uncertain and in any real sense "conservative", you will not use the uncertainty to justify foolhardy risks.
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