Global warming is causing changes in glaciers, permafrost and snow cover in Central Asia, threatening the livelihood of millions of people in the region. Nature spoke with Qin Dahe, a glaciologist at the Cold and Arid Regions Environment and Engineering Research Institute in Lanzhou and co-chairman of Working Group I of the Intergovernmental Panel on Climate Change (IPCC) at the International Symposium on Changing Cryosphere, Water Availability and Sustainable Development in Central Asia held last week in Urumqi, China, where he gave un update on the IPCC's work. Qin tells Nature how the panel is working to ensure scientific rigor in the upcoming assessment report, and what the world must do to tackle global warming.

In 2007, the IPCC's fourth assessment report mistakenly claimed that Himalayan glaciers could disappear by 2035. What's the current understanding of the situation?

The IPCC was not as rigorous as it should have been in citing a document that had not been scrutinized by the international scientific community. Despite the error, however, the bigger picture remains: it's clear that the majority of Himalayan glaciers are retreating at a rapid rate, which is consistent with new data on changes in glacial volume. The threat to the region's water resources holds, regardless of whether the glaciers will disappear in 20 years or 200 years.

What can we expect from the fifth assessment report in 2013?

There will be more data on changes in glacial volume as well as other components of the cryosphere, such as permafrost and snow cover. There is encouraging progress in the IPCC climate-modelling studies, with smaller gaps between observed and modelled global average temperature and carbon-dioxide concentration. We will be tackling questions such as whether climate change is accelerating, whether the Greenland ice sheet is stable, what roles clouds and aerosols have in climate forcing, and whether there will be more extreme climate events, such as droughts, floods, typhoons and hurricanes.

Why is the cryosphere particularly important for Central Asia?

Central Asia is a typical Eurasian inland environment, consisting of high-mountain cryosphere, lowland oasis and desert. Such a setting is heavily dependent on ice and snow, which act as reservoirs for redistributing precipitation. Changes in the cryosphere in the region, which are mainly a result of climate change, are threatening water resources and ecosystems.

How is China tackling dwindling water resources and desertification?

The water resource per capita in China is well below the global average, but in northwestern China it is actually quite high — several times higher than in Israel, for instance. But the concept of water conservation is lacking, so improving the efficiency of water use is the key. We are modernizing irrigation infrastructure by switching to drip irrigation. There are attempts to limit the overuse of groundwater. Researchers are also trying to grow vegetation in the region to mitigate and reverse desertification.

What are the main challenges of studying the cryosphere and water resources in Central Asia?

The biggest challenge is the lack of data at key locations, especially at high elevations. These include meteorological data, such as temperature, wind, rainfall and snowfall, and measurements of ice dynamics of glaciers and permafrost. Without such information, we cannot validate or improve our climate models. And when data does exist, it's hard to know who has it or how to get hold of them. The sharing of hydrological data related to international rivers faces another layer of complexity — one that concerns politics and diplomacy rather than science.

Given the deadlock of recent rounds of climate negotiation, what must the world do to limit and mitigate climate change?

Despite uncertainties, one thing is absolutely clear: global warming is real and poses a significant threat to civilizations worldwide, and reducing emissions of greenhouse gases can mitigate the problem. The process of climate negotiation has been frustratingly slow, but it's encouraging that the world has committed to a goal of keeping temperature increases to less than 2 ºC. Both developed and developing countries must work together to share the obligation of emissions reduction. We must act now. This is our moral responsibility towards future generations.

From http://www.nature.com/news/2011/111020/full/news.2011.604.html