Top Indian physicists have concluded Himalayan glaciers show little sign of retreat – in one of the largest studies of its type ever carried out.
I. M. Bahuguna et al, publishing in Current Science [PDF, issue index], studied changes to 2,000 glaciers in various Himalayan regions between 2001 to 2011. They conclude that 1,700 were stable, showing the same surface area and no change of direction.
248 glaciers exhibited a retreat, and 18 an advance. The scientists estimate a net loss of glacier area of about 10,000 km2 – that’s a 0.2 per cent decrease (+/- 2.5pc), and an average retreat of 2.1 metres annually.
Glacier melt is important to note because it presages rising sea levels in the future – although this can take a very long time, typically hundreds of years. The Indian boffins used satellite imagery backed up by selective field observation of their own. It confirms earlier research published in Nature that the Himalayas are in line with the historical natural warming trend.
Glacier extent reached its peak 22,000 years ago. Glacier retreat accelerated with the end of the last ice age, some 11,000 to 12,000 years ago. They’re expected to advance again when the current interglacial period comes to an end.
The advance of glaciers in the Karakorum region has been noted before. Some glaciers can retreat several hundred feet a year, prompting some scientists to use computer modelling and small sample sizes to generate alarming conclusions.
The Indian study, by contrast, uses empirical evidence and a sample size of over 2,000.
India stepped up its own scientific research after shoddy work was exposed in the 2007 IPCC AR4 report into climate impacts. That report claimed the Himalayan glaciers would disappear entirely by 2035, leading to widespread drought, starvation and migration. It was rubbish, as the unapologetic IPCC chairman Rajendra Pachauri, was forced to admit.