Solar Variation Has Little Effect On Global Warming

Variation in the brightness of the Sun is not the major factor behind
the unusual warming the Earth has experienced over the past few
centuries, a new study suggests.

Researchers traced changes in our parent star's energy output back
to the 17th century and found that solar cycles, peaking nearly every
11 years, did not play a significant role in contributing to global warming.

Earth's warming trend, which climate reconstructions show began in
the 17th century, has accelerated in the last 100 years.
Most studies reveal that this temperature rise could be attributed to the
increase of greenhouse gases in the Earth's atmosphere.

The researchers used a combination of data on solar brightness obtained
by spacecrafts since 1978 and isotope data —collected from Earth's
atmosphere and in ice sheets of Antarctic and Greenland—to recreate the
Sun's influence on terrestrial temperatures over the past several centuries.
Although events such as sunspots have increased in the last 400 years,
their effect only contributed a small amount to global warming, the results
show.

“Our results imply that, over the past century, climate change due to
human influences must far outweigh the effects of changes in the Sun's brightness,” said study co-author Tom Wigley of the National Center for Atmospheric Research.


SOURCE:
LiveSceince.com

Well, this would put to bed the sunt heory on Gloabl Warming.


Comments, Opinions?

I don't think it actually puts the whole solar theory to bed yet.
But it's interesting data.

I'd be curious as to the resolution of the data..If it take into account the possibilites of other, longer trends in solar activity. Or the Strengths of the known cycles.

Or even the possibility of one of those secondary cycles triggering something climatalogical in the 16th century. Previous to data they are using in the study.

What about the levels of cosmic dust within the ecliptic?

I think this data should just be plugged-in to other data..
Maybe someday we'll figure out what the recipe(s) for GLobal warming really is.



[edit on 13-9-2006 by spacedoubt]

I don't trust the conclusions reached in the study. For one thing the researchers only looked at direct temperature increases that could be attributed to the sun and then only at 27 years worth of data. What other changes might the sun's changing radiation pattern, spectrum, mass ejections, etc. have caused indirectly? There is certainly much more coming from the sun than just what we see as light.

No, I think I'll wait until several more studies come to the same conclusions via different routes.