Monday, June 29, 2009

Does the sun have more impact on climate change than humans?

Dear EarthTalk: Don't some scientists point to sunspots and solar wind as having more impact on climate change than human industrial activity?

- David Noss, California, Md.

Sunspots are storms on the sun's surface that are marked by intense magnetic activity and play host to solar flares and hot gassy ejections from the sun's corona. Scientists believe that the number of spots on the sun cycles over time, reaching a peak - the so-called Solar Maximum - every 11 years or so. Some studies indicate that sunspot activity overall has doubled in the last century. The apparent result down here on Earth is that the sun glows brighter by about 0.1 percent now than it did 100 years ago.

Solar wind, according to NASA's Marshall Space Flight Center, consists of magnetized plasma flares and in some cases is linked to sunspots. It emanates from the sun and influences galactic rays that may in turn affect atmospheric phenomena on Earth, such as cloud cover. But scientists are the first to admit that they have a lot to learn about phenomena like sunspots and solar wind, some of which is visible to humans on Earth in the form of Aurora Borealis and other far flung interplanetary light shows.

Some skeptics of human-induced climate change blame global warming on natural variations in the sun's output due to sunspots and/or solar wind. They say it's no coincidence that an increase in sunspot activity and a run-up of global temperatures on Earth are happening concurrently, and view regulation of carbon emissions as folly with negative ramifications for our economy and tried-and-true energy infrastructure.

The complete article on is here.

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