Wednesday, December 05, 2007

Will sun spots save us after all?

The Independent today report that the decline in sun spot activity observed in recent years may lead to a FALL in global temperatures of 1.5C by 2020.

This would nicely offset the predicted increases from man made global warming. Sorted. In fact it may more than offset any predicted increases.

Is it really that simple? It is never wise to give too much publicity to half baked scientific theories in case climate change skeptics use them as an excuse for "business as usual." These theories do have a certain level of scientific credibility however.

Ray of hope: Can the sun save us from global warming? [Independent]

Something is happening to our Sun. It has to do with sunspots, or rather the activity cycle their coming and going signifies. After a period of exceptionally high activity in the 20th century, our Sun has suddenly gone exceptionally quiet. Months have passed with no spots visible on its disc. We are at the end of one cycle of activity and astronomers are waiting for the sunspots to return and mark the start of the next, the so-called cycle 24. They have been waiting for a while now with no sign it's on its way any time soon.


The past decade has been warmer than previous ones. It is the result of a rapid increase in global temperature between 1978 and 1998. Since then average temperatures have held at a high, though steady, level. Many computer climate projections suggest that the global temperatures will start to rise again in a few years. But those projections do not take into account the change in the Sun's behaviour. The tardiness of cycle 24 indicates that we might be entering a period of low solar activity that may counteract man-made greenhouse temperature increases. Some members of the Russian Academy of Sciences say we may be at the start of a period like that seen between 1790 and 1820, a minor decline in solar activity called the Dalton Minimum. They estimate that the Sun's reduced activity may cause a global temperature drop of 1.5C by 2020. This is larger than most sensible predictions of man-made global warming over this period.


No comments: