TWO POWERFUL AND contradictory images come to mind when I’m asked to reflect on my experience of attending the United Nations Climate Change Summit in Paris. The first image (dated 12 December 2015) is of delegates leaping to their feet and cheering wildly as chair Laurent Fabius announces that – yes! – agreement has been reached on the Paris Agreement.

The second photo, taken only a few weeks later in Tasmania, is of the black and smouldering fire-scorched wasteland which was, until recently, home to some of the oldest and most magnificent of Earth’s forests. The stark contrast between these two images helps explain the two tough questions that continue to trouble the sleep of many climate scientists, policy makers and activists.