I think that all participants seem to agree that climate change is so slow as to be almost imperceptible over a lifetime, or several lifetimes. So at any one point in time the climate appears unchanging, motionless.
I think that all participants would also seem to agree that we’re currently living in a warm interglacial period that has lasted about 12,000 years. So the motionless pendulum is near one end of its swing. And all concerned are wondering what will happen next. And there’s no agreement about this.
Since most people never experience any climate change during their lifetime, most people think that there is no climate change happening. In their view the pendulum is motionless because it’s simply not swinging, or swinging so slowly that it’s hardly swinging at all. The lack of motion of the pendulum at right is indicated by the red dot on it.
Perhaps the strongest evidence that the climate really is changing comes from the Vostok ice cores, which show that the temperature of the Earth’s atmosphere has been swinging up and down by about 10º C every hundred thousand years for the last 400,000 years:
The Earth’s climate swings from one extreme to another, very like a rather irregular pendulum. It seems to warm up very quickly when an ice age ends, and cool down slowly when an ice age starts, and reaches its coldest just before this ice age ends.
Global warming alarmists think that the climate is warming, and the pendulum hasn’t reached the top of its swing. And they think that it’ll only reach the top of its swing when both the Greenland and Antarctic ice sheets have melted, causing a 60 m rise in sea levels. And they think that the pendulum is being given a kick upwards by the addition of CO2 to the atmosphere.
About 18 months ago I began to become a bit of a global cooling alarmist. I think that the pendulum has passed the peak of its upswing, and has begun its downswing. Just visible on the extreme right of the Vostok temperature graph above is a slight (1º C) downturn in air temperature over the past few thousand years, which is the prelude to a likely prolonged accelerating downswing in temperature. I’m not convinced that human CO2 emissions are sufficient to turn this incipient downswing into an upswing. And also I don’t think that CO2 is the sole determinant of the Earth’s climate. I think it’s just one of several factors affecting climate. I think (and I seem to be entirely alone in thinking this) that what happens during these cycles of glaciation and de-glaciation is very largely driven by the fall and rise in the temperature of the Earth’s surface rocks. When these rocks cool down, snow and ice can settle on them. And when deep layers of insulating snow and ice have built up on the surface of the Earth, they cause the surface rocks beneath them to warm up, and melt the overlying snow, and then start to cool.
So I think there are 3 legitimate positions that can be adopted. Firstly that the climate isn’t changing. Secondly that the climate is warming. And thirdly that the climate is cooling.
There might be a fourth position, which is that the climate is changing, but there’s no way that its behaviour can be predicted, because it’s far too complex, like the double pendulum shown at right. And there’s nothing we can do about it.
Each of these various positions is accompanied by recommendations for some sort of remedial action. Those who don’t think there is any climate change happening don’t see the need for any remedial action. Those who think that the climate is warming call for human CO2 emissions to be reduced or completely stopped. And those like myself who think that the climate is cooling will call for CO2 emissions to be if anything increased rather than decreased. So warmists and coolists will make opposing recommendations.
At present, it would seem that most people either don’t believe that there’s much climate change happening, or they believe that there’s nothing that we can do about it. And so they’re not prepared to undertake the kind of drastic action recommended by the warmists. They’re not significantly reducing CO2 emissions.
And from my coolist perspective, this failure to act to reduce CO2 emissions seems to be the exact right thing to be doing. Because the more CO2 gets added to the atmosphere, the longer the coming new ice age can be delayed. My only question is: how long can the inevitable be deferred?