Is it too little, too late or a milestone moment? The gavel has gone down on the annual UN climate summit, with a final declaration that for the first time recognises the need to "transition away" from fossil fuels. That was not a given when it was announced that the UAE, the world's seventh-largest oil producer, would be hosting COP28 in Dubai. As always, these summits conclude with statements of intention, at best. So how much will this one matter?