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Climate Change

Climate change is not a theory, a speculation or a conspiracy by environmentalists. Even the most hardened climate change deniers have realised that they can no longer credibly deny its existence or claim that it doesn't have anthropogenic ( man made ) origin. All they can argue about is the scale of its effects.

Imagine you are about to board a plane. On one side of the path through the airport are hundreds and hundreds of aircraft scientists. They are a bit shy and nerdy and don't shout too loud - but, having checked each others sums most carefully - they are saying that there is a 95% chance that your aircraft will crash. Opposite them, scientists of other disciplines shout loudly and persuasively that the aircraft is OK. It may be a bit broken but it will all be OK. Would you fly?

You are on our one planet. Hundreds of climate scientists have carefully checked each others working and have collectively concluded that warming of the climate system is happening, that it is caused by man made greenhouse gasses and that the earth is going to warm by something between 1.1 and 6.4 degrees C by 2100. Opposite them, another group shouts that the world is just a bit broken but will be OK. You can’t get off the plane this time though. You have nowhere to go. There is only one earth. We have to fix the problem.

The IPCC creates reports based on the consensus view of hundreds of peer reviewed climate science papers from all round the world. This approach tends to smooth out the predictions and ends up assuming that the relationship between greenhouse gasses and temperature are basically linear. If we add so many million tons of CO2 then the temperature will go up this much. From this they create the predictions above for 2100. This suggests that there is time to act. There are, however, rogue systems which are likely to upset this assumption. These are known as forcings. Balances between the forces involved in maintaining the earth’s temperature which, once they start to change, could make things happen much faster than the reports suggest.

Ice cover in the arctic is one of these. Summer ice reflects the sun's energy back into space and keeps the arctic ocean cool - but global warming has reduced the area of summer ice and replaced it with dark, energy absorbing, sea. The sea warms. The next year there is less summer ice. The sea warms more. A positive feedback mechanism creating additional warming over a period - until there is no more summer ice.

Arctic tundra is another. Thousands of square kilometres of frozen marshland, permafrost, made up of layers of vegetation laid down over hundreds of thousands of years. As climate change warms the soil, the frozen vegetation thaws and starts to decompose - giving off the greenhouse gasses carbon dioxide and methane. Potentially in huge quantities. Methane is of particular concern as it has at least twenty times the warming effect of the same amount of CO2 released. So, once again, global warming thaws the tundra. The tundra gives off methane. The methane causes more global warming. More tundra thaws. More methane. More warming






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