A coal-fired power plant in Datong, China. If the world stopped building new coal-fired power plants and manufactured no new cars or trucks, warming would remain well below a 2C increase. Photograph: Jason Lee/Reuters

If we were starting afresh, we probably wouldn’t chose to build an energy infrastructure based around fossil fuels. But like it or not, we are stuck with power stations, cars and homes that use carbon-based energy sources. The problem is that almost all these buildings and vehicles last a long time. If they stay in use, we are committed to large-scale future production of greenhouse gases. But how large?

Technicians start work on draining the vast underground lake beneath the glacier. Photograph: Jean-Pierre Clatot/AFP/Getty Images

Viewed from up here, the world of man appears very small and vulnerable. The Tête-Rousse glacier, hovering between sky and earth at an altitude of 3,200 metres, dominates the scene splendidly. It is a magnificent panorama of infinite horizons, the perfect silence interrupted only by sound of the climbers’ crampons as they start the ascent to Aiguille du Goûter, the normal route up Mont Blanc. Facing us, the Aravis range and the Chablais Alps break up the horizon, while in the valley below, tiny chalets appear to be clinging to the mountainside.

But the serenity is deceptive. In the core of the glacier lies a silent threat that could, without warning, destroy the village of Saint-Gervais below. Trapped under the glacier lies an enormous 65,000 cubic metre pocket of water – the equivalent of 20 Olympic swimming pools – that could burst and surge down on to the village below. “It’s impossible to predict when that might happen,” said Christian Vincent from the Grenoble Laboratory of Glaciology and Geophysical Environment. He is here to carry out a regular temperature check at Tête-Rousse.

The 75 metre-deep glacier covers 8 hectares of a rocky basin. Early this summer, several boreholes were pierced with a high-pressure hot water drill and special sensors introduced on to the bedrock. Using a snow shovel, the scientist clear the markers that show where these were placed and note down the temperatures. “Precise knowledge of a glacier’s temperatures is vital to understanding how these water pockets are formed,” Vincent explains.

It has been a summer of record temperatures – Japan had its hottest summer on record, as did South Florida and New York. Meanwhile, Pakistan and Niger are flooded and the eastern US is mopping up after hurricane Earl. None of these individual events can definitively be attributed to global warming. But to see how climate change will play out in the 21st century, you needn’t look to the Met Office. Look, instead, to the deaths and burning tyres in Mozambique‘s “food riots” to see what happens when extreme natural phenomena interact with our unjust economic systems.