Saul Perlmutter was in philosophical mood when the BBC spoke to him about the issue.

BBC: Dark discussion ahead for Europe and US

Saul Perlmutter and Adam Riess of the US and Brian Schmidt of Australia will share the Nobel.

BBC: Dark discussion ahead for Europe and US

This was the approach used by the Nobel Prize winners (Saul Perlmutter and Adam Riess of the US and Brian Schmidt of Australia).

BBC: Euclid telescope to probe dark universe

Riess shared this year's prize with with fellow American Saul Perlmutter and the Australian Brian Schmidt for the discovery, back in 1998, that the expansion of the Universe is accelerating.

BBC: Getting the measure of dark energy

When embarking on the project 18 months ago, its members (including Saul Perlmutter, who won the Nobel prize for physics this month for his work on dark energy) were mostly new to climate science.

ECONOMIST: Climate change