Barack Obama is being pressed for proof of his intent to act on climate change ahead of next week's United Nations global warming summit in Doha.
The proof might boil down to just two words: two degrees. An early statement at Doha that America remains committed to the global goal of limiting warming to 2C above pre-industrial levels would be a clear sign.
Every statement from US diplomats at the Doha negotiations will be closely scrutinised for signs that Obama will indeed make climate change a priority of his second term – and that America remains committed to the global agreement diplomats have been seeking for 20 years.
Campaigners say Obama's re-election, superstorm Sandy and New York City mayor Michael Bloomberg's endorsement – predicated on climate change – put climate change back on the domestic agenda.