Science - Historical Data Show Solar Output Changes = 3% Of Observed Warming

[hatrack]

Don't blame the sun for recent global warming. A new analysis, based on historical data rather than computer simulations, shows that our star's role in climate change has been vastly overtaken by other factors, particularly the human-induced buildup of greenhouse gases.

We get our warmth from the sun, sure, but our climate results from a complex and precarious balance of additional factors, including ocean currents, winds, the amount of snow and ice cover, and even Earth's orbit and rotational wobble. It's well-known that our climate has been warming over the past century--a situation most researchers blame on human-induced buildup of carbon dioxide, methane, and other greenhouse gases. Studies have shown that the sun was a driving factor in climate change in preindustrial times, but some researchers have wondered whether changes in the sun's intensity are continuing to play a major role, possibly by hitting the planet with more heat than normal.

To help nail down the effect of solar radiation, geophysicist Mike Lockwood of the University of Southampton, U.K., examined data available since 1955 on the monthly average output of the sun, including sunspots, magnetic activity, and cosmic-ray variations. Then he compared those data, month by month, with average global temperature records, as well as El Niño- and La Niña-induced weather cycles and the atmospheric effects of major volcanic eruptions. The result, Lockwood and colleagues report in two papers published online this week in the Proceedings of the Royal Society A, is that for the past half-century, the sun has exerted only a small influence on climate--about 3% compared with the warming influence of greenhouse gases and natural climate cycles (see illustration).

Lockwood says a key advantage of his approach is that he relied on hard data rather than computer models. "One problem that crops up is that scientists use complex models that nonspecialists don't understand and therefore don't trust," he explains.

EDIT

http://sciencenow.sciencemag.org/cgi/content/full/2008/312/3

[papau]

1. I doubt Fox News will report this

[hatrack]

2. No, they've tasked their part-time science report to reporting the Daily Tech story . . .

:eyes:

[ben_meyers]

3. Again a caveat

Studies have shown that the sun was a driving factor in climate change in preindustrial times, but some researchers have wondered whether changes in the sun's intensity are continuing to play a major role, possibly by hitting the planet with more heat than normal.

It was but now it isn't? Now there's some hard scientific facts.

[OKIsItJustMe]

5. Again a misrepresentation

It's still a factor. However, greenhouse gases are a much larger factor.

[GliderGuider]

6. The sun is an active, dynamic body that goes through periodic changes

It's not a static, constant, uniform energy emitter. I'm not sure what would be controversial about a finding that there is less solar activity today than in times past. Except for the fact that it upsets some peoples' agendas, of course.

[NickB79]

7. Climate change has sped up dramatically since pre-industrial times

The sun caused climate change over millenia in the past, but humans are causing the same amount of change in decades.

An analogy would be a car rolling down a hill. Gravity is causing the car to accelerate slowly. Now the driver stomps on the gas and the car accelerates rapidly. Gravity is still causing the same amount of acceleration, but the driver's actions have overshadowed it greatly.

[Nihil]

8. Excellent analogy!

> An analogy would be a car rolling down a hill. Gravity is causing the car
> to accelerate slowly. Now the driver stomps on the gas and the car
> accelerates rapidly. Gravity is still causing the same amount of
> acceleration, but the driver's actions have overshadowed it greatly.

I'll try to remember that one for future use!
:applause: :toast:

[OKIsItJustMe]

9. Very good! Let me try to extend it

Gravity causes the car to roll down hill. The driver stomps on the gas, and the car speeds up dramatically. Gravity is still accelerating the car, but the driver's actions currently have a much greater effect.

The driver slowly becomes aware that the car is headed for a cliff (a "tipping point.") Once the car goes over the edge, there's nothing the driver can do to stop its accelerating plunge. The question is, can the car be stopped before it goes over the cliff?

[jimlup]

4. A useful article

Thanks Hatrack, you do a good job collecting information for us. I've come to rely on your posts for that.