I’m a bit of a passive activist, i.e. not the sort that joins demonstrations waving banners, shouting slogans. But I do want to get the BAGW (Beneficial Anthropogenic Global Warming) message out, so I figured that if I ever had a decent win at lotto, I would place a full-page advert in the local newspaper (in my case, The West Australian). I’m still waiting for the cheque from lotto, but here’s what I had in mind.
I am assuming that the reader is not a scientist, so the prose is a little simplistic. I’m keeping well away from any political slant :-).
CLIMATE CHANGE – Beyond the Politics
Do you believe in Climate Change? Yes? So do the ‘sceptics’ and ‘deniers’ – climate is, and has been, constantly changing.
Do you believe in Global Warming? Yes? So do the ‘sceptics’ and ‘deniers’ – it has been warming for the last 400 years, and 0.8°C since 1850.
Do you believe that humans have contributed to this warming? Yes? So do the majority of ‘sceptics’ and ‘deniers’ – CO2 has undoubtedly warmed the planet, it is a ‘greenhouse’ gas, and its effect is generally accepted as ‘settled science’.
Is the current global warming going to prove ‘catastrophic’ in the future? This is where the uncertainty lies. The UN’s IPCC (Intergovernmental Panel on Climate Change) ‘consensus’ and the current government believe the current warming will continue unabated, to reach between 2°C and 4°C (or higher) above current temperatures by the end of this century. However, for the last 10 years the temperature has stopped rising. We all know that the earth’s weather occurs in natural cycles (and climate is the average of the weather), from daily warm/cool cycles, to yearly warm/cool cycles. We also have longer climatic warm/cool cycles, like the ENSO cycle (El Niño/La Niña, every 4-7 years), the Hale Cycle (~21 years) the Pacific Decadal Oscillation (~64 years), the cycle between the Roman, Medieval and current warm periods (~1100 years) and the cycle between the major ice ages (~120,000 years).
The climate is currently recovering from the “Little Ice Age” ( the cold period between the Medieval and current warm periods, 1600-1800), and we have just passed the maximum (as of 2005) of the current Pacific Decadal Oscillation (~64 years). The present global temperature appears to be entering a cooling phase, and if history is a guide, should continue to be slightly cooler for the next 20-30 years, before warming slightly again (see graph below).
It is agreed by both the IPCC scientists and ‘sceptics’ that a doubling of CO2 into the atmosphere will only raise the global temperature by about 1°C, directly. The difference in opinion concerns the ‘side-effects’ (positive and negative feedbacks) of the 1°C rise.
Simply put, the IPCC and government think that it will get warmer still as more water vapour enters the atmosphere due to evaporation, and water vapour is a much more effective ‘greenhouse’ gas than CO2, resulting in ‘run-away’ temperatures.
The ‘sceptics’ agree that more water should enter the atmosphere, but suggest that more cloud will form as a result, reflecting more incoming radiation (heat) from the sun back into space, thereby cooling the earth, operating like a thermo-stat. We all know that the earth has experienced cataclysmic events in the past, such as meteor strikes and major, violent volcanic eruptions, and the earth’s climate has always recovered, suggesting that the climate is inherently stable, or self-regulating. A minor 1°C rise in temperature from a CO2 doubling is extremely unlikely to cause a ‘run-away’ temperature rise.
However, the science is extremely complex, and admittedly not well understood by either side of the debate. The empirical evidence (i.e. the global temperature) suggests that the future temperature projections of the climate computer models are way off mark (see graph below). If observations don’t match projections, then the projections (and the theory behind those projections) are wrong. Regarding the politics and policies based on this theory? That’s for you to decide. Just remember that the ‘Precautionary Principle’ is counter balanced by the ‘Law of Unintended Consequences’.