In the Wuwei Oasis, a small agricultural enclave in northern China that supports around 300,000 people, water levels are so low that the region is now merging with nearby deserts. This image is part of a series on the Chinese 'dust bowl' by Photographer Benoit Aquin, who last month took home the first Prix Pictet, a major new award for photographs that depict sustainability issues.

China is one of many countries worldwide affected by worsening desertification. Formerly a 'silent crisis' localized in regions home to 75 per cent of the world's poor, the spread of deserts is caused largely by bad land use practice. But, according to one senior UN environmental official, it has recently been pegged as a global problem because of its connection to climate change.

Speaking ahead of the UN Convention to Combat Desertification (UNCCD) conference held 3 to 14 November in Istanbul, where experts met to thrash out details of a ten-year strategy to address the issue, UNCCD Executive Secretary Luc Gnacadja said “The nexus between land degradation and climate change is clear”.

“If we want to tackle climate change challenges, we must look to the untapped potential of the soil to sequester carbon,” added Gnacadja. For now, signs suggest that lands are losing that potential: a UN report released in July found that between 1981 and 2003 an additional 24 per cent of the world's land became degraded and less productive, while just 16 per cent of land became more fertile.

To stop its spreading sands, which cover 18 per cent of the country, the Chinese government recently set aside a fifth of its grasslands for restoration, and herding communities have been relocated en masse. The harsh measures may succeed in recovering land and carbon stores — if they are not overwhelmed by droughts yet to come.