Read the headlines – “Asia’s Glaciers Putting on Mass [i]” and you may be mistaken for thinking all this climate change talk is nonsense. If the world is getting warmer, how can a large ice sheet continue to grow?
The glaciers in question are those on Asia’s Karakoram Mountains, and despite producing drinking water for an estimated 1.3 billion people, they are relatively unknown. Unfortunately no polar bears wander across this wilderness and its impassable access routes makes it hard for researchers let alone film crews to delve into its heart – so maybe Sir David is forgiven for not giving it a mention in Frozen Planet.
The claims have come from a French team, who used satellite data to show that glaciers in part of the Karakoram Range, to the west of the Himalayan region, are putting on mass – they are growing. The team found that between 1999 and 2008 the mass of the glaciers in this 5,615 sq km (2,168 sq miles) region of the Karakoram increased marginally, although there were wide variations between individual glaciers. This is in clear contrast to the 2007 report by the Intergovernmental Panel on Climate Change (IPCC) containing the bold claim that ice from most of the region could disappear by 2035.
The reasons behind the anomaly are poorly understood but several studies hint that the climate in the Karakoram may be cooling, contrary to the trend in most of the world. Between 1961 and 2000, weather stations in the region recorded an increase in winter precipitation and a decrease in average temperatures during the summer. And during the same 40-year period, average flow volume for one of the region’s rivers, which is fed by glacial melt water, was 20% below normal.
However, in line with global trends, studies using the same techniques as the French guys have shown that most parts of the Himalayas are actually losing mass. Measurements by the GRACE satellite mission, which detects minuscule variations in the Earth’s gravitational pull, have also shown a net loss of mass across the whole region. Furthermore, late last year, the Kathmandu-based International Centre for Integrated Mountain Development (Icimod) released data showing that across 10 regularly studied glaciers, the rate of ice loss had doubled since the 1980s.
(Although a mere 10 intensively studied glaciers among a total of more than 54,000 is hardly comprehensive).
Therefore it appears that a fraction of the Himalayan ice sheet may have grown, but in general the ice is melting. So what impact will this have on global climate, and to the lives of the billion that live in the river basin it feeds?
The 2007 IPCC report suggested that the melting glaciers would cause the Ganga, Indus, Brahmaputra and other rivers that criss-cross the northern Indian plain to become seasonal rivers in the near future as a consequence of climate change. A change to seasonal rivers would have huge impacts on agriculture in the region, not to mention causing fresh water crisis. Other effects could be to slightly reduce the albedo effect on the earth (reflection of the sun’s rays) and to alter weather patterns and distribution – locally and on a wider scale.
However, this prediction that the rivers could dry up may be unfounded, as models appear to show that it is the regional snow melt, and not the glacial itself that feeds the rivers. Only 10 to 20 per cent of the dry-season flow comes from glaciers themselves.
Initial studies of how the rivers will respond to ice loss show modest changes in stream flow — far from the IPCC report’s dire scenario of rivers running dry. Even if the glaciers were lost completely, some researchers argue that flows down the Indus would only drop about 15 per cent overall, with little or no change in the dry-season flow. Nevertheless climate models are poor at simulating rain and snowfall, and given the nature of the Asian monsoon, reliable models would be near impossible to ascertain.
But to me a 15% drop in flow, seems fairly dramatic. The world’s population is predicted to soar to 9bn by 2050, with the majority of growth in areas such as those supplied by these rivers. Even if these rivers do not dry up, the impact of a 15% decline in fresh water must be substantial for the productivity and subsequent health of the region.
Undoubtedly more efficient agricultural methods need to be transferred to developing regions such as these, and research is required to produce greater yielding crops for example, but surely we can’t neglect the impact that loosing 1/6th of their annual freshwater could have.
More field studies are in desperate need in the Karakoram Mountains. We need to know why some of these glaciers are growing, but we also need to thoroughly investigate the possible impacts that climate change will have in this relatively unknown region.
Headlines such as these probably don’t help the situation either as there is no doubt that climate change is happening and the majority of the world’s ice stores are melting.
The impacts will inevitably be monumental, but unfortunately for the people of the northern India and the like, it is they who will face the hardest challenges.
[i] On the BBC homepage as of 15/04/2012
[ii] Glaciology: No ice lost in the Karakoram, Graham Cogley, Nature Geoscience doi:10.1038/ngeo1456
[iii] Settling the science on Himalayan glaciers, Nature Reports Climate Change Published online: 2 March 2010 doi:10.1038/climate.2010.19