Natural processes involving changes in the Sun could have at least as powerful an effect on global temperature as increased emissions of carbon dioxide (CO2).

BBC: Viewpoint: The Sun and climate change

They have discounted the effect of both on the temperature increase over the last century because they either happen over too short a timescale, or they are too weak.

BBC: Viewpoint: The Sun and climate change

These - along with ambient temperature and other factors - can have a dramatic effect on performance.

BBC: Novice Nico Hulkenberg upstages Fernando Alonso

"We do see these big variations in the temperature in the mantle across parts of Antarctica that will have a big effect on the ice sheet, " Wiens said.

MSN: So what really is going on under the Antarctica ice?

After all, what do pre-industrial world temperature trends have anything to tell us about the effect of man-made Co2 on 20th century temperatures?

FORBES: Did CLOUD Just Rain on the Global Warming Parade?