[LINK] Weekend Magazine - Remote Siberian Lake Holds Clues to Arctic--and Antarctic--Climate Change

[Gordon Keith]

On Tue, 26 Jun 2012 08:25:34 AM TKoltai wrote:
> Following is Hansen's summary, blaming the primary causes to be
> variations in Volcanic Aerosols and possibly solar luminosity.

> Quote/
> Summary. The global temperature rose by 0.20C between the middle 1960's
> and 1980, yielding a warming of 0.4°C in the past century. This temperature
> increase is consistent with the calculated greenhouse effect due to measured
> increases of atmospheric carbon dioxide. Variations of volcanic aerosols and
> possibly solar luminosity appear to be primary causes of observed
> fluctuations about the mean trend of increasing temperature.

> /quote

Tom,

I think you misunderstand what is written. 

Hansen is stating that there is a warming trend of 0.4°C caused by CO2 and 
that trend is hard to see because of noise around the signal caused by  
variations in volcanic aerosols and possibly solar luminosity.

The primary cause of the _variations_ is volcanic aerosols and possibly solar 
luminosity.

The cause of the _warming trend_ is greenhouse effect of CO2.

Regards
Gordon