A short history of climate change

It will possibly be my last book, but Not Your Usual Science is going to be HUGE, close to 1.5 million words, equal to a dozen 'airport books', the thick tomes you buy to read on a long flight. It collects together many of the articles and essays that I have generated over the past 35 years, covering science, how science works and how what we now call science was put together. It even includes some of the blog entries that have appeared here. In due course, it will be released as an e-book.

Here's a small taste of it, but let me add here that in late March 2019, a circular from Rush Holt at AAAS 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 bit into my weekend a bit. Here is a link to the paper in question. Her short piece begins on p. 382, and here is a key comment: "An atmosphere of that gas [carbonic acid, CO2] would give our earth a high temperature..."

Now I have to go back and amend the book to add this!

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Jens Galschiot's installation 'Unbearable' in Copenhagen. [Peter Macinnis]

If the illustration above seems rather savage, the J-curve on which the polar bear is skewered reflects the graph of the inexorable rise of atmospheric carbon dioxide, and the curve is made from a length of oil pipe. Art and politics go together very well.

Here is some surprising news: we knew that “global warming” was happening, way back in 1950! Now, of course, most reputable atmospheric scientists believe human activity is driving the modern slow warming of our climate, but back then it was just a passing reference that came my way.

All the same, now we know that global warming is a bad description, so we call it ‘climate change’. Under any name, it’s the same beast, and the same looming disaster, and we knew it was happening, two thirds of a century ago.

Mind you, the knowledge that humans are to blame is even older, because as we will shortly see, 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 is likely to be biased by a generous serving of self-interest. That has changed in the last ten years.

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 2 – 300 miles (call it 400 kilometres), adding that farmers in southern Ontario were experimenting with cotton. While that industry seems not to have taken off, 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.

The matter open to question back then was the cause. Kimble noted that 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 also looked at Biblical evidence on the distribution of date palms to suggest that conditions in 1950 were much those of Biblical times, providing a picture of a climate that fluctuates around a mean. Maybe it was just one of those cycles.

That was in a time before ‘global warming’ when climate change was referred to as the ‘greenhouse effect’. In cold climates, a greenhouse is a glass shed which allows sunlight to shine in, where much of the radiation is absorbed and changed to heat.

Glass is less transparent to heat, but a greenhouse does not just 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, but that goes way back to those early predictions.

In the 1820s, Joseph Fourier realised that heat-trapping might occur. Then 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 get 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 a very small part of the total in the air already, perhaps one part in a thousand was added by the burning of coal, and there were probably checks and balances.

Arrhenius estimated that it would take 3000 years to double the atmospheric levels of carbon dioxide, if it ever happened, but that such a doubling would raise world average temperatures by 5 to 6°C.

Back in 1896, when Arrhenius did that calculation, the CO₂ level was around 290 parts per million: in 2016, the value was estimated at 396 parts per million: we had travelled one third of the projected distance in just 120 years.

To Europeans back 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. Walter Nernst, even wondered 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 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 analogy, just as the early 1960s saw us hung up on “continental drift”.

That aside, the cost of disagreement and bickering is remarkably different. 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 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.

To take one example, the formation of sea ice in the northern Atlantic is probably what stops Dublin and New York being iced-in each winter. This is because the sea ice is largely free of salt, and leaves 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 many 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 pattern, we may not be able to bounce it back to where it started.

The good news is that as northern Europe freezes over, the glaciers which are now melting away fast 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 actual changes that might follow the breaking point are hard to predict. They are unlikely to be spectacular and major, and probably they will do their harm 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, and then have to face the voters again.

It is easier to bleat plaintively that there is no real agreement among the scientists yet (even when there is), or that some eminent scientists believe that there are other explanations (they don’t: 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 aren’t sure…”

Politics is a marvellous human discovery. It is a pity that politicians still have to discover humanity and consider its prospects. It is likely that politics, dithering, duck-shoving and shilly-shallying will make this disaster happen.

The reader is referred to my comments about “future value” in the piece preceding this, called A Question of Values. So long as the electorate value their comfort right now, over the comfort of their grandchildren, we are doomed like the bears.