Bru Pearce Blogs
It’s a fact; carbon dioxide in the atmosphere traps the Suns energy. In the last 200 years man has nearly double the amount of carbon dioxide in the atmosphere by burning fossil fuels. The heating caused by increased CO2 levels means that there is more evaporation leading to higher levels of water vapour in the atmosphere which is even more potent as a greenhouse gas. In this respect CO2 is acting like a thermostat turning up the CO2 turns up the heat.
One of the few pieces of scientific consensus that came out of the big Copenhagen climate conference was that an increase of any more than 2°C would be extremely dangerous, with a real likelihood that anything above this would lead to runaway climate change.
By observing the correlation of atmospheric CO2 to ice cover and temperature, laid down in the geological records of the past 800.000 years, we can determine that the mean temperature of the Earth can be expected to increase by between 4 and 6°C for every doubling of atmospheric CO2. This can be described as the earth system sensitivity to CO2 increase. We also know that there is about a 30 to 40 year lag in the time it takes for temperature to increase due to the inertia in the system, mainly due to the heat absorbed by the oceans. It’s as if we are charging up a giant night store heater.
The majority of the excess CO2 has been added to the atmosphere over the past 40 years. So far global temperatures have only risen by around 0.8°C. But the most recent Earth system sensitivity data shows that we are already committed to 3°C and that this is coming through quite quickly.
We are being misled
Our consumption of hydrocarbons is continuing to rise; if you look at the optimistic predictions of the IPCC they suggest that we can add about 565 gigaton's of carbon to the atmosphere before we drive over 2° C, but here we are at 0.8° C warming and already the Arctic Sea ice is disappearing and weather patterns are change across the globe. So far we have only burnt something like 320 gigaton's, we are on track to have burned 565 gigaton's by mid century, by which time we will be set up for 6°C of warming. But the madness does not stop; there are a further 2,795 gigaton's of proven coal, oil and gas reserves that our hydrocarbon companies are planning to burn and against which finance is secured. That’s 5 times more than the very optimistic upper limit!
I should point out that another of the consistent things that has come out of IPCC predictions is that they have nearly all proven to be way off target, with temperatures rising higher and faster than predicted. For example, the prediction was that we would not have an ice free Arctic Sea until near the end of the century. It now looks as if we will have an ice free Arctic by 2015 and almost certainly before the end of the decade. This year there was far more open water in the Arctic than ever before and as a result we are already experiencing major climatic shifts, swinging between deluge and drought and hot and cold all over the world. With the result that world agricultural output is down overall by as much as 20%, the likelihood is that next year will be considerably worse than this, and the year after that worse again. There is no hiding from it we have broken the Arctic and cascading effects of food shortages and escalating food prices will follow ensuring that there will be no recovery from recession. Major natural disasters of increasing frequency and intensity will further add to the financial stress on the system.
Another consistent thing about the assumptions we are presented with, is that despite us being told that there are numerous feedback loops in the climate system, rising temperature, sea level and the frequency of increase in extreme weather events are all presented as steady linear increases. Unfortunately feedback loops are by their nature exponential, the further along the line you are the more sharply it turns up. And we are already a long way down the line!