In 1994, I stood at the foot of the mighty Athabasca Glacier in the heart of the Canadian Rocky Mountains. At places more than 300 metres thick, the ice was treacherous, riven by great fissures and studded with rocky debris carried down from the Columbia Icefield, seven kilometres away. We had parked our car outside the chalet, a kilometre or so behind us, and traversed the moraine stretching across the treeless valley. As I waited for a break in the clouds before taking a photograph, it was disconcerting to consider that, one hundred years earlier, my vantage point would have been compressed under tons of slowly flowing glacial ice. Indeed, the glacier then extended beyond the site of the current Chalet carpark. This was my first direct experience of global warming. With such compelling evidence of climate change, it is not surprising that award-winning photo-journalist and environmentalist Gary Braasch begins his book on global warming with matched images of the Athabasca Glacier taken in 1917 by A.O. Wheeler, and in 2005 by Braasch himself.