Climate change at least partly natural

A European study further complicates the already complicated Global Warming debate:

A Bonn study shows that since 1880 climate gases have caused just under half of global warming.

"Without the influence of the greenhouse gases the average annual temperature would have only increased by 0.4 degrees," is how Professor Andreas Hense summarises the results.

'However, the fluctuations at the end of the 19th and in the first half of the 20th century are mainly due to changes in solar activity and volcanic eruptions.'

So, is the glass half empty or half full?