Ice Age Sized Holes in the Case for Anthropogenic Climate Change
The belief that human activities, especially of the type seen in industrial and post-industrial societies, are somehow responsible for “global climate change” previously known as “global warming” is an established article of faith among a significant percentage of the population in many countries. Hardly a day goes by without an article in some news outlet, mainstream or otherwise, proclaiming the discovery of yet another piece of evidence for anthropocentric climate change. While the intensity of the rhetoric has diminished somewhat since its last peak in 2006-2008, it is clear that the number of hardcore believers has not diminished.
While I am certainly not the first one to point it out- a lot of the rhetoric and beliefs associated the anthropogenic climate change believers are strikingly similar to traditional guilt-based religions such as Catholicism. Many aspects of this new belief system such as appeals to the authority of “approved” experts, secret knowledge that can only be understood by the initiated, persecution of dissenters or “climate change deniers”, constant talk about the dark and malevolent forces that want to make true believers stray from the righteous path are essentially identical to those seen in other traditional religious and secular belief systems.
However this post is not about how the environmental movement is a secular version of Catholicism- which it is. Instead, I am going to point out one obvious, but seldom discussed, problem with the idea that current levels of human activity are causing significant climate change.
What was responsible for the last few ice ages and the interglacial periods in between them?
As some of you might already know, the last 3 million years have witnessed a series of glacial events separated by interglacial events collectively known as Quaternary glaciation or Pleistocene glaciation. During this time period continental glaciers were repeatedly able to push to (and sometimes below) 40 degrees longitude in many parts of the world, including north america.
In addition, a zone of permafrost stretched southward from the edge of the glacial sheet, a few hundred kilometres in North America, and several hundred in Eurasia. Each glacial advance tied up huge volumes of water in continental ice sheets 1,500 to 3,000 metres (4,900–9,800 ft) thick, resulting in temporary sea level drops of 100 metres (300 ft) or more over the entire surface of the Earth. The effects of glaciation were global. Antarctica was ice-bound throughout the Pleistocene as well as the preceding Pliocene. The Andes were covered in the south by the Patagonian ice cap. There were glaciers in New Zealand and Tasmania. The current decaying glaciers of Mount Kenya, Mount Kilimanjaro, and the Ruwenzori Range in east and central Africa were larger. Glaciers existed in the mountains of Ethiopia and to the west in the Atlas mountains.
But what does any of this have to do with anthropogenic climate change? Aren’t ice ages and interglacial periods a ‘natural’ phenomena? Didn’t most of them occur before anatomically modern humans evolved?
Well of course they are a ‘natural’ phenomena and that is precisely the problem. It also does not help that industrial civilization, did not exist during any of the ice ages or interglacial periods- other than the interglacial we are currently living in and which started about about 12-15k years ago. So what caused such large and relatively abrupt (on a geological time scale) changes in the earths climate? How do you go from an extended interglacial period of many tens of thousands of years to a fairly sustained glacial period of many tens of thousands of years and then back to another interglacial period?
What factors drove these massive global climate changes and more importantly- are those factors still relevant and active?
You might have heard about the Milankovitch cycles, but even they don’t fully explain the phenomena of Quaternary glaciation. There is also the issue of the various ice ages starting and ending at slightly different times in different parts of the world. For example- the second last glaciation cycle in N. America, the Illinoian (191-130 k years ago), does not run parallel to its equivalent in the British Isles, known as the Wolstonian (325k-130k years ago). While the last ice age started and ended at somewhat similar times throughout the world, it had its own warmer and colder periods– and this was likely the case for the earlier ones too. My point is that even climatic events as large and prolonged as global ice ages do not display high levels of uniformity, stability or predictability.
And this brings us to the fundamental problem with modeling any large, complex, poorly understood and adaptive system. How can you model the primary and secondary effects of slight changes to one parameter (a slight increase in atmospheric CO2 effects) when the dynamics of the underlying system components are poorly understood. Let me explain that with a simpler analogy. Can you confidently measure the effects of drinking an extra cup of tea or coffee per day on a large population, if you did not first have a good understanding of human physiology, society and lifestyles. And would an extra cup of tea or coffee per day have a statistically significant effect that could stand above the noise and fluctuations in the collected data?
So how can you confidently calculate the effect of small changes in one minor parameter on a semi-predictable and ever-changing baseline that is capable of far bigger variations than your cherished effect? To put it another way- can you really measure an effect if the baseline variations are much larger than the said effect?
What do you think? Comments?