Global warming is a crucial issue. And recently Russil Wvong wrote a lengthy and thorough response to my IRPP post on the subject that, in turn, deserves a thorough response. I don’t want to create a tedious and largely impenetrable he said/he said exchange here, but since the essence of debate is a reasoned and systematic examination of the issues I think it makes sense to tackle his points in order.

To begin with, he invokes the lamentable flat-earth analogy to suggest that it is easy to think the climate is stable. True. But I have never said the climate is stable. On the contrary, in writing about global warming over more than a decade I have insisted that the climate is so remarkably unstable that it cannot be mathematically modeled at all. It is, technically, ”œnon-linear” and in an age committed to the proposition that linear algebra can explain everything from chemistry (mostly true) to economics (wildly false) we generally assume without reflection that it can also explain climate.

Not so. And it is not me, but the alarmists with their ”œhockey stick” that shows a very stable global temperature until the 20th century, who would have you believe everything was orderly and harmonious until human wrongdoing expelled us from a temperate Eden into a lake of fire.

Wvong goes on to say that the debate on warming really is over, because

”œAtmospheric CO2 traps heat. We can measure this directly. We can directly measure the level of CO2 in the atmosphere and see that it’s steadily increasing. Thus we can expect the amount of heat trapped by the atmosphere to increase over time.”

Now this syllogism is appealingly simple. But it is utterly wrong. We cannot measure directly how atmospheric CO2 traps heat. How would we? You can’t put a thermometer in the Earth’s mouth. We can’t build a series of otherwise identical Earths and release different amounts of CO2 into their atmospheres. What direct measurement does he have in mind?

As Tom Harris of the International Climate Science Coalition has noted, because we do not have any measurements at all from most of its surface even today we have very little idea what the temperature of the Earth actually is now, let alone what it used to be before the Industrial Revolution. And even if we did, we could not directly measure the impact of CO2 because so many things are going on at once in the climate.

It is true that we can measure the level of CO2 in the atmosphere and see that it is increasing. But we cannot project a continued linear temperature or even CO2 increase because of the complexity of the interaction of atmospheric CO2 with climate including feedback loops.Wvong_CO2

Finally, we cannot expect the amount of heat trapped by the atmosphere to increase over time, both because we cannot directly measure how atmospheric CO2 affects temperature and because, as Wvong unwittingly goes on to demonstrate, increasing levels of CO2 have not caused Earth’s temperature to increase in the past. So it is more than a little odd to insist that we know, absolutely know, they will now do so.

Russil Wvong’s post includes an impressive set of graphs of temperature and atmospheric CO2 (and dust) over the past 400,000 years. And as he notes, theydo show them moving more or less together (which, interestingly, does not seem to be feature of the Earth’s temperature over a longer time scale, something his discussion of how ”œas paleoclimatologists continued to reconstruct past climate records” skeptics ”œbecame increasingly rare” does not mention).

The problem is that even with the naked eye you can see that in those reconstructions, CO2 concentrations rise and fall after the associated temperature changes not before them. It is rising temperature that causes increases in atmospheric CO2 not the other way around.

Wvong_CO2_superimposed

I even overlaid them for you (sorry they’re blurry but the originals weren’t high rez.) But don’t take my word for it. Ask Russil Wvong.

As he said in his post, ”œThe ice ages were actually many pulses of cold glacial phases interspersed with warmer interglacials. These pulses had a distinct regularity caused by wobbles in Earth’s orbit around the Sun (Milankovitch cycles). When Earth’s orbit reduced the intensity of sunlight in the northern hemisphere, the Earth went into a glacial phase. When the orbital cycle brought increased the intensity of insolation in the northern hemisphere, ice sheets melted and we went into a warm interglacial. Because warmer oceans can dissolve less CO2, the CO2 levels see-sawed extremely closely with Earth’s temperature.”

There you have it. Warmer oceans release more CO2. More CO2 does not warm oceans. Until now.

Thus if we are to believe the alarmists, the very laws of climatic causation reversed when man discovered fossil fuels. But true science does not, as I have also repeatedly noted, work that way. It is a fundamental rule of science that we cannot posit changes in physical laws. If we do, it becomes impossible to make any sense at all of what used to be ”œevidence” when we had causal mechanisms to explain it. (Incidentally, his charts suggest dust rises before temperature does. Perhaps we need anti-dust initiatives.)

Speaking of how science works, Russil Wvong also says ”œMy question to global-warming skeptics is always: Can you explain (step-by-step) how increasing CO2 is not going to result in global warming?” Which is like demanding a step-by-step account of how purple dragons are not going to destroy our city before questioning preparations to fend them off.

The proper question is ”œCan you explain (step-by-step) how increasing CO2 is going to result in global warming?” And the alarmists cannot. Indeed, they cannot even explain what has caused dramatic swings in the Earth’s climate in the past when increasing CO2 concentrations appear to be an effect not a cause. Nor can they explain why in the past once CO2 levels had risen we did not get a ”œgreenhouse” effect instead of warming trends suddenly and unpredictably reversing and resuming despite the alarmists’ models suggesting bleak stability.

Wvong does say that, based on wobbles in the Earth’s orbit (Milankovitch cycles), climate has been cooling for a few thousand years, heading for another glaciation around 3500 AD. Now, he says, we’ve messed all that up. But, leaving aside the undesirability of another glaciation for our posterity, look again at his chart of temperature changes over the past 400,000 years. Notice the endless abrupt changes.

What makes him think we’re not just in one of those now? Again, it is not science to suggest that although the Earth’s climate has witnessed an uncountable number of sudden drops or rises in temperature for natural reasons, the one we’re now in, if we are, cannot be of that sort and must be an entirely new kind where CO2 is suddenly and unaccountably driver not passenger.

I actually pity the alarmists in that they have decisively won the public debate, if not the scientific one. But they cannot devise practical responses so they resort to winning the debate again and again. In his post Wvong says ”œthe scientific debate was over by the late 1980s” which leaves me a bit puzzled why I keep reading, every year or two, that it has finally ended, the latest model really does the trick, only fools, Flat-Earthers and oil company flacks now deny it and so on. It’s a bit like that business where if the locals don’t understand you when you speak English, you shout it at them.

At the end Wvong says that global warming is an appalling collective action problem. And I grant that if the alarmists’ science is right, so is their economics: We need to do something, we need to do it together, and while that sort of action is hard, difficulty is no excuse for inaction in the face of impending disaster. Here his logic is impeccable.

The problem is that his scientific logic is nothing of the sort. It relies upon misreading the very evidence he triumphantly unveils, reversing the laws of causation in the 20th century when it comes to climate and atmospheric CO2 without explanation, ignoring the much longer sweep of climate history and the influence of solar cycles, and accusing his adversaries of simplistic climate models when his own is actually far too simple.

Let me concede one final point to the alarmists. Climate is alarming. That we do not know what it’s going to do next, and could not change it if we did, actually is far more alarming than anything Al Gore ever said. But it’s the truth. Climate is non-linear. We cannot usefully model or predict it. And a massive global campaign based on bad science that weakens our economies and ability to adapt without doing a darn thing about the weather is no rational response to that frustrating problem.