Contributor(s): Professor Steven Bernstein, Professor Barry Buzan, Dr Robert Falkner, Professor Kathy Hochstetler | Climate change and other environmental threats have moved to the top of the international agenda. All major powers are now committed to fighting global warming and ensuring environmental sustainability. But it has not always been thus. How did the society of states come to accept a responsibility for the global environment? And how deeply committed are states to safeguarding the planet?