The Paris Climate Conference begins today, a landmark event with participation expected to exceed 40,000 people and 147 heads of state or government, significantly more than the roughly 115 who attended the previous attempt at a global climate deal at Copenhagen in 2009. Climate data from this year suggests that a global rise in temperature of 1ºC, already halfway to the 2ºC maximum set by a consensus of climate scientists, has now taken place, and protests against government inaction have already begun.

Can hopes of a new deal on climate change be fulfilled, or will the conference lose momentum? Will the US and China, long accused of dragging their feet over environmental policy to safeguard economic growth, take a leading role? Whatever your view, send it in - via Twitter, Facebook or our website. The contributors with the best insights will be invited to explore their views further for our journal Sir!