Is the Sun Responsible for Global Warming?

[Gokul43201]

New paper published in the Proceedings of the Royal Society A:

Authors
Mike Lockwood (1, 2), Claus Fröhlich (3)

1 Rutherford Appleton Laboratory, Chilton, Oxfordshire OX11 0QX, UK
2 Space Environment Physics Group, School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, UK
3 Physikalisch–Meteorologisches Observatorium Davos, World Radiation Center, 7260 Davos Dorf, Switzerland

Abstract

There is considerable evidence for solar influence on the Earth's pre-industrial climate and the Sun may well have been a factor in post-industrial climate change in the first half of the last century. Here we show that over the past 20 years, all the trends in the Sun that could have had an influence on the Earth's climate have been in the opposite direction to that required to explain the observed rise in global mean temperatures.

"Recent oppositely directed trends in solar climate forcings and the global mean surface air temperature", Mike Lockwood and Claus Fröhlich, Proc. R. Soc. A doi:10.1098/rspa.2007.1880 (2007)

http://www.journals.royalsoc.ac.uk/content/h844264320314105/[/URL]

Review of paper in Nature News: [URL]http://www.nature.com/nature/journal/v448/n7149/full/448008a.html[/URL]

[quote]Nature 448, 8-9 (5 July 2007) | doi:10.1038/448008a; Published online 4 July 2007

[b]No solar hiding place for greenhouse sceptics[/b]

Quirin Schiermeier

A study has confirmed that there are no grounds to blame the Sun for recent global warming. The analysis shows that global warming since 1985 has been caused neither by an increase in solar radiation nor by a decrease in the flux of galactic cosmic rays (M. Lockwood and C. Fröhlich Proc. R. Soc. A doi:10.1098/rspa.2007.1880; 2007). Some researchers had suggested that the latter might influence global warming through an involvement in cloud formation.

...

Together with Claus Fröhlich of the World Radiation Center in Davos, Switzerland, Lockwood brought together solar data for the past 100 years. The two researchers averaged out the 11-year solar cycles and looked for correlation between solar variation and global mean temperatures. Solar activity peaked between 1985 and 1987. Since then, trends in solar irradiance, sunspot number and cosmic-ray intensity have all been in the opposite direction to that required to explain global warming.

In 1997, Henrik Svensmark, a physicist at the Danish National Space Center in Copenhagen, suggested that cosmic rays facilitate cloud formation by seeding the atmosphere with trails of ions that can help water droplets form (H. Svensmark and E. J. Friis-Christensen [i]J. Atmos. Solar-Terrest. Phys.[/i] [b]59[/b], 1225–1232; 1997). He proposed that, as a result of this, changes in the Sun's magnetic field that influence the flux of cosmic rays could affect Earth's climate. This led to claims that cosmic rays are the main influence on modern climate change.
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Other news articles:

[PLAIN]http://environment.newscientist.com/article.ns?id=dn12234&feedId=online-news_rss20[/URL]

[url=http://news.bbc.co.uk/1/hi/sci/tech/6290228.stm]BBC: Science/Nature [/url]

 

[ZapperZ]

Global Warming Is Driven by Anthropogenic Emissions: A Time Series Analysis Approach

This paper has appeared in several news reports already, and I don't know if anyone has mentioned it in this forum. So if it hasn't, here it is.

Pablo F. Verdes, Phys. Rev. Lett. 99, 048501 (2007).

Abstract: The solar influence on global climate is nonstationary. Processes such as the Schwabe and Gleissberg cycles of the Sun, or the many intrinsic atmospheric oscillation modes, yield a complex pattern of interaction with multiple time scales. In addition, emissions of greenhouse gases, aerosols, or volcanic dust perturb the dynamics of this coupled system to different and still uncertain extents. Here we show, using two independent driving force reconstruction techniques, that the combined effect of greenhouse gases and aerosol emissions has been the main external driver of global climate during the past decades.

Yes, it's a physics paper, written by a physicist. A press release can be viewed here.

Zz.

 

[Skyhunter]

ZapperZ,

There is a lot of activity in regards to aerosols.

Here is a letter in Nature from Ramanathan. He is also a physicist with the Scripps Institute

Correspondence to: Veerabhadran Ramanathan1 Correspondence and requests for materials should be addressed to V.R. (Email: vramanathan@ucsd.edu).
Top of page

Atmospheric brown clouds are mostly the result of biomass burning and fossil fuel consumption1. They consist of a mixture of light-absorbing and light-scattering aerosols1 and therefore contribute to atmospheric solar heating and surface cooling. The sum of the two climate forcing terms—the net aerosol forcing effect—is thought to be negative and may have masked as much as half of the global warming attributed to the recent rapid rise in greenhouse gases2. There is, however, at least a fourfold uncertainty2 in the aerosol forcing effect. Atmospheric solar heating is a significant source of the uncertainty, because current estimates are largely derived from model studies. Here we use three lightweight unmanned aerial vehicles that were vertically stacked between 0.5 and 3 km over the polluted Indian Ocean. These unmanned aerial vehicles deployed miniaturized instruments measuring aerosol concentrations, soot amount and solar fluxes. During 18 flight missions the three unmanned aerial vehicles were flown with a horizontal separation of tens of metres or less and a temporal separation of less than ten seconds, which made it possible to measure the atmospheric solar heating rates directly. We found that atmospheric brown clouds enhanced lower atmospheric solar heating by about 50 per cent. Our general circulation model simulations, which take into account the recently observed widespread occurrence of vertically extended atmospheric brown clouds over the Indian Ocean and Asia3, suggest that atmospheric brown clouds contribute as much as the recent increase in anthropogenic greenhouse gases to regional lower atmospheric warming trends. We propose that the combined warming trend of 0.25 K per decade may be sufficient to account for the observed retreat of the Himalayan glaciers4, 5, 6.

 

[cbacba]

That makes sense, but I wouldve guessed the sun would be gradually cooling, even if the helium from the burned hydrogen undergoes nuclear fusion, it still wouldn't produce as much heat. So sooner or later, wouldn't this be the case and everything begin to cool?

Sorry but the 'habitable zone' is headed outward. Estimates are an increase of 40% in the last few billion yrs. It will continue and the oceans should boil off before we ever hit the red giant phase, where our current orbit will be inside the sun. This apparently will be in hundreds of millions of years and not billions of years when the oceans boil.

 

[TR345]

I have read that Venus has unusually high surface temperatures. Does anyone know of any recent and or important discoveries, or research on Venus and the cause of its' high temperatures.

 

[cbacba]

I have read that Venus has unusually high surface temperatures. Does anyone know of any recent and or important discoveries, or research on Venus and the cause of its' high temperatures.

It's not exactly new but there's a number of reasons. It's much closer to the sun. It's not really rotating at any speed so the days are ridiculous. It's got an atmosphere with about 900+ PSI (versus our atmosphere's 14.7 PSI of pressure) of almost pure CO2 like a giant ocean of pea soup thick gas, with virtually an earthlike atmosphere riding atop it kilometers above the surface and conditions not particularly different from Earth way high above the CO2 'ocean'. It's got what appears to be massive amounts of current or relatively recent volcanic activity and there are all sorts of highly reflective clouds (sulphur compounds etc). Also, there doesn't seem to be much water vapor there, at least not enough to form an ocean were it to cool off below boiling point. It's possible that the water once existed and later disassociated in the atmosphere and it's possible that it never existed there.

From what I understand, there's only a couple of photos from the surface done by a russian probe many years ago. It's pizza oven hot down there and otherwise it sort of ressembles some of the martian landscape. Exploring the surface is rather out of the question since our electronic technology isn't capable of surviving at that teemperature as it's just about hot enough to melt solder and cook transistors fairly quickly.

Whether venus ever ressembled Earth as it exists now or whether Earth ever ressembled venus now is a good question. Somewhere along the line, Earth seems to have established chemical mechanisms to suck up all the massive amounts of CO2 and stuff it into limestone etc. Later, life forms started doing similar things after they got started. If venus never had the oceans or water vapor, it may never have had the means to dispose of all the CO2 that was there. Having no fairly short day like most planets, there would tend to be a significant heat build up on the daytime side so things wouldn't work very well even without the massive CO2 'ocean'