US President Barack Obama has said that for nations to be accountable on greenhouse gas emissions, legally binding “periodic reviews” are needed.

“If we have these periodic reviews built in, what I believe will happen is that, by sending that signal to researchers and scientists and investors and entrepreneurs, and venture funds, we’ll actually start hitting these targets faster than we expected. And we can be even more ambitious,” Obama said during a news conference at the climate change conference (COP21) in Paris.

Turning to Syria, Obama said he does not expect to see a 180-degree turn on Russia’s strategy over the coming weeks.

“I don’t think we should be under any illusion that somehow Russia starts hitting only ISIL targets: that’s not happening now, it was never happening, it’s not gonna be happening in the next several weeks. What can happen is, if the political process that John Kerry has so meticulously stitched together in concert with foreign minister Sergey Lavrov from Russia, if that works in Vienna, then it’s possible that we start seeing at least pockets of ceasefire in and around Syria”.

Obama said he believes Moscow eventually may align itself with the US-led coalition fighting ISIL militants.