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Friday, 2 July 2021

A changing climate

Jens Galschiot’s installation
‘Unbearable’ in Copenhagen.

 In the savage illustration on the left, the J-curve skewering the polar bear reflects the graph of the unstoppable rise of atmospheric carbon dioxide, and the curve is made from lengths of oil pipe. Sometimes, art and politics go together very well.

Did you know scientists knew about global warming, well before we usually think? Today, reputable atmospheric scientists everywhere are certain that human activity is driving the modern changes in our climate, but in 1950 it was just a curiosity. Of course, ‘global warming’ is a bad description, so we call it ‘climate change’ now. Under any name, it’s the same beast, the same looming disaster, and we knew about it, two thirds of a century ago.

Nobody denies that the Earth is getting warmer, because the evidence is there, and it was apparent in 1950, when George Kimble reported in Scientific American that the northern limit of wheat-growing in Canada had moved northward some 200 to 300 miles (call it 400 kilometres), adding that farmers in southern Ontario were experimenting with cotton. While cotton seems not to have taken off there, he reported another trend that continues to this day, the northward retreat of the permafrost:

In parts of Siberia the southern boundary of permanently frozen ground is receding poleward several dozen yards per annum.

Was it a cycle? Kimble said the Domesday Book featured 38 vineyards in England in 1086, in addition to those of the Crown. He pointed also to the Greenland colony which was frozen out, back around the mid-1400s and other evidence that climates change. He looked at Biblical evidence on the distribution of date palms to show that conditions in 1950 were much those of Biblical times, providing a picture of a climate that fluctuates around a mean. Maybe the trends were all just part of one of those cycles.

Mind you, the knowledge that humans are to blame is even older, because the whole thing had been predicted. The problem before was that there was not a lot of hard science in the arguments, which come down to logic, reason, careful modelling—and interpretation that was likely to be biased by a generous serving of self-interest. That changed in the last ten years.

Before ‘global warming’, climate change was called ‘the greenhouse effect’. In cold climates, a greenhouse is a glass shed which lets sunlight shine in, where much of the radiation is absorbed and changed to heat. Glass is less transparent to heat, but a greenhouse does more than trap warmth that way: it also holds a body of warm air around the plants, and protects them from wind-driven evaporation. So while we still speak of ‘greenhouse gases’, it is rare to hear anybody mention the greenhouse effect these days, even if the term goes way back to those early predictions.

Still, 1950 wasn't when it all began. In the 1820s, Joseph Fourier realised that heat-trapping might occur. In 1896, Svante Arrhenius reminded us that both water vapour and carbon dioxide were ‘greenhouse gases’ (escaping that bad analogy is hard) and so water and carbon dioxide would play a role in making the planet warmer. 

He also considered changes that might be happening, and consulted Arvid Högbom, who just happened to know all about carbon dioxide sources and sinks. Carbon dioxide was coming from life forms when they breathed, from volcanoes, and from humans burning fossil and other fuels. The human additions were minimal, perhaps one part in a thousand was added by the burning of coal, and there were probably checks and balances. 

Let's say 1896, OK? I mean, that was the story, I thought, but in late March 2019, a circular from Rush Holt at the American Association for the Advancement of Science (AAAS, of which I am a member) drew my attention to Eunice Foote:

Let me add one interesting historical note that is not widely known. In 1856 at the AAAS Annual Meeting, the work of Eunice Foote was presented, showing that carbon dioxide is a heat-blanketing greenhouse gas that in the atmosphere could warm the Earth. This was years before the work of the men usually credited with the finding (Tyndall in England and Arrhenius in Sweden).

Well, that broke into my weekend a bit. Foote’s short piece in The American Journal of Science and Arts in 1856 begins on p. 382, and says: “An atmosphere of that gas [carbonic acid, CO2] would give our earth a high temperature …”

Arrhenius thought it would take 3000 years to double the atmospheric CO2 levels, if ever, but such a doubling would raise world average temperatures by 5 to 6°C. In 1896, when Arrhenius did his calculation, the CO2 level was around 290 parts per million: in 2021, the value was estimated at 420 parts per million: we had travelled almost half of the projected distance in just 125 years. Now look at the angle of that pipe, the one skewering the bear!

To Europeans in the 1890s, the warming effect seemed nothing to worry about, because nobody had stopped to consider the cascades, the flow-ons that might be driven by that rise in temperature. A German chemist, Walther Nernst, even asked if it would be feasible to set fire to uneconomical and low-grade coal seams, so as to release enough carbon dioxide to warm the Earth’s climate deliberately!

In the 1990s, global warming was in much the same position that “continental drift” had been in, a generation earlier, with some of the scientists arguing furiously, even when they agreed on the main principles, and as in the puzzle of the wandering continents, the key evidence was right there. Mind you, when I covered the 2002 Spring Conference of then American Geophysical Union, there were no nay-sayers there. The problem is that so long as people can get away with saying “global warming”, we are once again stuck with a bad label, just as the early 1960s saw us hung up on “continental drift”.

The cost of disagreement and bickering is much higher with climate change. It mattered not at all if people disagreed about plate tectonics (except, perhaps, that it makes tsunamis like the 2004 Indian Ocean tsunami easier to understand), but under any name, global warming is likely to be a major disaster for humanity, and any delay has the potential to cost lives. To understand this, we have to accept some puzzling propositions.

The formation of sea ice in the northern Atlantic is probably what stops Dublin’s and New York’s ports being iced-in each winter. This is because the sea ice is largely free of salt, leaving a residue of cold brine that drives a current known as the Conveyor, which in turn drives the Gulf Stream. The Gulf Stream takes warm water from the Caribbean and swirls it up around the North Atlantic, contributing to fogs and breaking icebergs loose, but keeping northern ports warm and open, even in winter.

Just as the prion proteins of mad cow disease have more than one stable form, so do weather patterns, and if the weather once drops into a new stable pattern, we may not be able to bounce it back to where it started. Then again, as northern Europe freezes over, the fast-melting glaciers will be replenished, lowering sea levels. The increased snow cover will also increase the reflectivity of the northern hemisphere, and that may cool the planet down a little. We just have to hope it does not trigger a new stable pattern that happens to be an ice age.

The changes that might follow the breaking point are hard to predict. They are unlikely to be spectacular and major, and will probably act stealthily, when infrastructure, port facilities and cities are flooded, or when agricultural land is lost, either by being covered by the sea or as a result of drastically changed rainfall patterns.

If any significant amount of rock is exposed in Antarctica, this could lead to a low pressure zone over the icy continent that could change weather patterns around the world. It hasn’t happened yet, but we need to learn from history. Ten years ago, no politician would take a long-term view and force the changes needed in the next thirty to forty years, when most of them are elected for a mere three to four years, after which they have to face the voters again.

It’s easier to bleat plaintively that there is no real agreement among the scientists yet (even if there is), or that some eminent scientists believe in other explanations (they aren’t all that eminent: just look at where the funding of these “scientists” comes from). That load of bollocks saves the politicians from having to act—and the honesty of scientists in saying that they cannot be sure just how things will go wrong allows devious short-term opportunists to prate that “the scientists don’t know…”

Politics is a marvellous human discovery. It is a pity that politicians have yet to discover humanity and consider its prospects. It is likely that politics, dithering, duck-shoving and shilly-shallying will make this disaster happen. So long as the electorate value their comfort right now over the comfort of their grandchildren, they are doomed.

We must care about the young: they are delicate. I will turn to how the young develop next.

1 comment:

  1. Hey there Peter, I didn't expect you to post any of that I was just pointing out the lack of comprehension in society in less literate circles. Even if the pollies listen to the scientists they can only do things appealing to the electorate. Remember when as kids we would go away on holidays and not even bother to lock the house doors? Now we live in constant fear of theft. Everything seems to come down to the lowest common denominator. As a reader of science and history (and Crooked Mick etc) myself, your frustration must be unimaginably worse than mine. I think that was all that I was trying to say in a rambling way.

    Funnily enough too when I was in the Never Again Volunteer Yourself (abreviation required!) in Sydney, North Head was my relief from the rest of the world. I understand your love of it.

    Must go now for your sake,