I’ve gotten a lot more interested in global warming/climate change over the past four months. I was gradually losing interest in it up until then, because it all seemed a bit passé. Is anyone much interested in it these days?
My resurgence of interest was a consequence of having my own surprising new idea about it. I say surprising because I’ve been unsuccessfully trying to get my head around global warming for the past 10 years and more, and didn’t expect to have any ideas about it at all. But 4 months ago I surprised myself with a new idea.
The new idea was very simple. It was that when the Earth gets buried under ice, as it periodically does these days, the ice acts as a layer of insulation on the ground beneath it, and the ground warms up (in exactly the same way as people warm up when they put on clothes). And when the ground has warmed up enough, it melts the ice on top of it. And when the layer of insulating ice has been removed, the surface of the Earth cools down (in exactly the same way that people cool down when they remove clothes). And when it’s cooled down enough, the ice starts to settle on its surface again, and builds into ice sheets. And this cycle of warming and cooling keeps on repeating, over and over again. At the outset, when the Earth was hot, the periods of glaciation were short, and the interglacial periods were long. But these days, millions of years later, with Earth having cooled further, the periods of glaciation are long, and the interglacials short. We’re currently living in one of these brief interglacials. It’s lasted some 10 – 20,000 years, depending on where its start point is taken to be. And it was preceded by about 100,000 years of glaciation, with the ice sometimes 4 km thick.
Strangely, climate scientists seem to be completely unaware of this very simple cycle (which I’m currently getting working in a computer simulation model, which is approaching completion). As far as I can make out, they regard the Earth itself as pretty much a non-participant bystander in matters of climate. They seem to see it as something that just slowly and steadily loses heat at a more or less constant rate (about 65 milliwatts per square metre of surface). They think that what drives the climate is the Sun and the Earth’s atmosphere, and maybe a few other things like El Niño ocean temperature oscillations.
A few days ago I got hold of a 2012 Scientific American article on one explanation of the end of the last glaciation:
Roughly 20,000 years ago the great ice sheets that buried much of Asia, Europe and North America stopped their creeping advance. Within a few hundred years sea levels in some places had risen by as much as 10 meters—more than if the ice sheet that still covers Greenland were to melt today. This freshwater flood filled the North Atlantic and also shut down the ocean currents that conveyed warmer water from equatorial regions northward. The equatorial heat warmed the precincts of Antarctica in the Southern Hemisphere instead, shrinking the fringing sea ice and changing the circumpolar winds. As a result—and for reasons that remain unexplained—the waters of the Southern Ocean may have begun to release carbon dioxide, enough to raise concentrations in the atmosphere by more than 100 parts per million over millennia—roughly equivalent to the rise in the last 200 years. That CO2 then warmed the globe, melting back the continental ice sheets and ushering in the current climate that enabled humanity to thrive.
That’s quite a long and complicated explanation. But basically it’s a variant of the religion of global warming alarmism with which we’ve all become familiar over the past 20 years or more.
And I think I can begin to see why it’s become a religion. And it’s that the climate scientists have been scratching their heads looking around for an explanation for repeated glaciations, and CO2 was the only thing they could come up with. And explaining this cycle of glaciations is arguably pretty much the biggest and most important puzzle us humans need to solve, because if we don’t we’re quite likely to be plunged into a new ice age sometime soon. And if rising CO2 in the atmosphere is what ended the last glaciation, rising CO2 in the atmosphere right now could well end up cooking us all. So it’s a matter of the greatest possible urgency to shut down the flow of CO2 into the atmosphere from burning coal and oil and gas. And hence all the zealots demanding that we all go carbon-free. It’s a matter of life and death.
The paper accompanying the Scientific American article seemed to suggest that it was a 3.5ºC temperature rise that had melted the ice 15,000 years ago, and so I’ve been calculating how long it would take for a cubic kilometre of ice to be melted by air 3.5º warmer than it. And I came up with an interesting result, which was that all the ice would be melted in about 10,000 years if the cubic kilometre of it had been fragmented into 16 separate blocks, because if it was just one block in a sheet of ice being heated by the atmosphere through its top surface alone it would take 650,000 years to melt it all. So I think that the climate scientists have been assuming that the ice sheets of the last glaciation were as fragmented by deep crevasses as the glaciers found in Greenland and elsewhere today. Now it’s understandable how glaciers sliding down undulating slopes could become fragmented, but why would large sheets of ice sitting on flat plains (like the US midwest or the Russian steppes) do the same?
Anyway, now that I’ve got my own theory of ice ages, which is very different from the one discussed above, I see the entire current global warming/climate change debate through new spectacles. I think it’s all much simpler than they – both climate alarmists and climate sceptics – think it is. Although I won’t be too surprised if some climate scientist takes one look at my idea, and immediately points out some obvious flaw in it – one that I still can’t see.