We had walked for what had seemed like miles. From the outskirts of the town of Listvyanka, we trekked through the driving wind and snow, to the fringes of the woodland and then through the forest.

It was cold but refreshing, invigorating but hard work and my toes and fingertips were going through various stages of numbness and pain. We had made our way out of the forest to follow the coast back and, beneath our feet, one-fifth of the planet’s fresh water was frozen.

Now we were retracing our steps, covering the same distance in a little over 15 minutes, a snowmobile rumbling beneath me as we glided across the ice. When the engine cut out, we were miles from Listvyanka and its familiar shore. This was a desert landscape of snow and ice, the banks at the farthest end of the lake some 636km away and well beyond the horizon. Here, in the heart of winter, in one of the toughest, most hostile climates in the world, was a place of silence and beauty.

Lake Baikal lies in south-east of Siberia, its southernmost tip just a few hundred kilometres from the border Russia shares with Mongolia. A popular stop on the Trans-Siberian route, Baikal is the deepest lake in the world, stretching almost a mile towards the Earth’s core. In October, as the Siberian winter sets in, the lake begins to freeze over, only thawing again in April, after which visitors can peer over the edge of a boat and see crystal clear water to a depth of 50 metres.

Some 336 rivers flow into Baikal, but only the mighty Angara flows the other way, and this influx of water leads to a 2cm growth in the lake each year. These rivers, say environmentalists, are under threat from a new US$11 billion oil pipeline earmarked to cross eastern Siberia to the Pacific Ocean by 2008. Also under threat are the fragile ecosystems which flourish right across the Baikal basin: 70% of the species found in the lake can be found nowhere else in the world. Greenpeace says the region’s high seismic activity puts the 4130km pipeline at risk of rupturing, potentially triggering an environmental and ecological disaster.

Yet despite efforts to cut worldwide greenhouse gas emissions, the backers of the pipeline, the state-owned Transneft oil corporation, see a growing market for Siberian oil in China, Japan, South Korea, India, Indonesia and Australia. The Russian Prime Minister, Mikhail Fradkov, approved the blueprint for the pipeline on New Year’s Eve, with annual capacity expected to reach 80 tons.

With reports suggesting the project has Japanese backing to the tune of several billion dollars, ecologists representing five environmental organisations, including Friends of the Earth, the WWF and Greenpeace, last month called upon Japanese Prime Minister, Junichiro Koizumi, to lobby the Russian government and Transneft to review the pipeline’s proposed route through Lake Baikal and a number of other fragile wildlife reserves. Local ecologists working for the Baikal Environmental Wave, a non-government organisation, have written an open letter to Russian President Vladimir Putin urging him to order further risk assessments before allowing the project to proceed.

A Transneft overview of the project maintains a minimal rate of environmental influence” would be witnessed at Lake Baikal and other areas of concern across Siberia.

The lake, which Unesco listed as a world heritage site in 1996, has remained remarkably resilient despite years of alleged abuse at the hands of paper and pulp mills which have been accused of discharging waste into its pristine waters.

If environmentalists and ecologists lose their battle to have Lake Baikal spared, and if their worst fears are realised, one of the most unique and bewildering places on Earth could be at risk. As we whizzed across the lake’s icy surface, I wondered if I’d ever see the likes of such beauty again.”