On the site we now have a a simple little graphic that shows how much heat has accumulated on our planet. It is expressed as multiples of of the heat energy of Hiroshima sized A-bombs.
I’ve picked 1979 as being the start year because that was the year that I became aware of the effects of changing climate. I was a 19 year old student in my second year of a BSc in Earth Sciences at Waikato university, and the topic under discussion was the WMO’s recent World Climate Conference (good precis of it here).
The basic science that I’d accumulated was sufficient to get the idea of how much climate has varied over the last 1000 million years and how much it’d affected the evolution of life. The last 40 million years or so have been in a ice age that was caused by Antarctica drifting into the south polar location, separating from Australia, and causing the circumpolar currents and air-flows to drop it into the freezer.
Our species entire 3-4 million year evolution had been punctuated and forced by the glacials. In 1979 recent work in the mid 70′s on deep sea cores had shown the glacials to be in a roughly 100,000 year cycle1.
In the late 70′s I was also reading deeply into history of our civilisations in the past 10,000 or so years. With a background of earth sciences resonating in my head with the massive climatic shifts over millions of years, it wasn’t hard to see how damn lucky we humans had been.
After nearly going extinct as a species a number of times in the last 100,000 years, we’d hit a strangely unusual period of climatic tranquility. We built a civilisation in the shelter of the secure food supply that agriculture in a stable climate can bring. It has been what has enabled us to grow a population from thousands to billions with a a globe-spanning civilisation running a ruddy great big communications network, a global economy, and an orbital infrastructure.
The problem is that it is all still built on top of agriculture. And our agriculture, in fact all agricultural patterns we know of depend on a climatic stability that is pretty abnormal and precarious.
So back to the insert from Skeptical Science. Adding an additional heat equivalent of 4 Hiroshima bombs per second in additional heat into our planets volatiles is a foolhardy idea. The excess heat has mostly been sucked up in the volatiles that make up the oceans. Most of the remainder has been warming the solid water back into the liquid higher heat retaining form in the polar areas2. But the heat hasn’t gone away, it is accumulating.
In climatic terms, the oceans provide our main climate and weather features. As they suck up heat and release it in different parts of the globe, they also moderate it. Living on smallish islands like we do in NZ, you really notice it whenever you go to a continental climate. They so damn cold in winter and excessively warm in winter. That is because land locations far from the oceans are more directly reflect the annual cycles of lengthening and shortening days.
But even in those landlocked locations the majority of the heat differences are buffered directly or indirectly by the oceans. Warm more energetic air bodies move towards colder regions like oceans which slurp up their heat. Oceans warmer than the air excrete heat to warm it. This heat exchange cycle provides much of our climate and weather patterns. It is a pattern that has now been relatively stable throughout out entire history as a civilised species.
So what happens when you keep tossing massive amounts of extra heat into the oceans? More heat means more energy. More energy means that the weather transporting heat is going to be more energetic. Over the remaining decades of this century it isn’t going to be good if you’re a farmer because the weather is going to start changing on you faster and faster. It might be warmer overall, but that just means more extreme mixing of the summer/winter differences. In other words bigger cold winter storms as polar air is pushed to warmer areas. More rain in places that don’t currently get it. Less rain in places that currently do. But most importantly less ability to predict how the temperatures will equalise themselves – at least for the next few thousand years.
We may be able to compensate partially by predicting weather and climate more accurately. But the problem is that we can generally predict climate over decades a whole lot better than we can predict what happens on a year by year basis. I feel that the farmers are going to be clean out of luck especially if the corporates continue to make money out of their carbon reserves by *burning* them!
If the farmers wind up having big difficulties, then the rest of us will as well.
1. We now know that the 100ky cycle is likely to be a result of interactions between the forcings of the Milankovitch orbital resonance cycles and the internal climate system oscillations. We don’t fully understand why this cycle happens at that resonance, but in a lot of ways it simply doesn’t matter. At the current rate we’re going, we’re unlikely to be civilised enough to observe the next one anyway.
2. Nothing makes me shudder as much about the lack understanding of basic science as the illiterates who sometimes try to say that recent higher snowfalls in East Antarctica is a indication that global warming isn’t real. Huh?
Extra precipitation in a icy desert that for at least the last 20k years has on average received less than 50mm of precipitation as snow per year. Are they fools?
Firstly it won’t increase the ice mass as any excess mass will simply cause an increased flow of ice over the underlying mountains to the sea. Secondly it means that more heat in the form of air moisture turning to ice is managing to penetrate into the inland areas of east Antarctica. That means that the long term trend in the freezer of the world is that it starting to defrost. Oh shit!
For the nostalgia buffs, this posts front page image is here.