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Today is Blog Action Day 2009. Many thousands of bloggers writing in scores of tongues are posting on this year’s subject – Climate Change – in an attempt to open up debate and inspire action.

There are few people left claiming that the climate is not changing, so there are two main camps: Those who believe the change is manmade and those who believe it’s part of a natural cycle. There is science to back both up. But why assume it has to be one or the other?

There are many natural cycles that affect our environment, not least of which is that affecting the thing that actually warms our planet – The Sun. Hot plasma moves in two great circuits deep within The Sun together known as The Great Conveyor Belt. When the area near the surface is hot and active sunspots form – small slightly cooler areas. There is a direct correlation: the more sunspots, the greater the intensity of solar radiation.

The Great Conveyor Belt has been determined by NASA scientists to have been travelling at around 1 metre per second steadily for the last century. However, now (based on sunspot observations) it has slowed, with the northern branch reduced to 0.75 m/s and the southern branch way down at 0.35 m/s. The result is that sunspot activity, which normally varies on a predictable 11 year cycle, is reducing, and the cycle is slowing down. NASA predicts the next peak of activity (after the current one) to be “off the bottom of the charts”, ie extremely low, with a corresponding reduction in The Sun’s output.

Graph showing NASA’s predictions for sunspot activity as of 2006 (Actual sunspot activity for current Cycle 24 so far is below that predicted)

As records for top temperatures continue to be regularly broken, such as the 46 degrees Celsius reached by Melbourne on Black Saturday this year, this is of great concern. If revised climate change projections are already close to ‘worst case scenario’ levels, as many climate scientists are saying, how bad will things get when solar output returns to normal levels? This might not happen for another 30 or more years, but happen it will. And if we haven’t done all we can to reverse manmade climate change by then... ...we’re toast!

Graphics: NASA Science; www.blogactionday.org