Striking back

First there was the scandal of the leaked emails (actually ‘hacked’ would be a better description). Now there is the news that the Himalayan glaciers are not, in fact retreating and will not therefore disappear by 2035. The first story was timed to appear just before the Copenhagen conference. The second is designed to bury its bones. Is this pure coincidence?

The second almost certainly, but the first equally certainly not. But what can’t be ignored is that, coming one after the other, they have dealt a massive blow to the credibility of the science that underlies the battle against global warming, and the IPCC’s credibility in particular.

Says James Delingpole, the ‘Daily Telegraph’ blogger whose claim is that ‘he is always right’,  “in the course of a garbled phone conversation a scientist accidentally invents a problem that doesn’t exist.” Needless to say, the Business As Usual lobby — the oil, shipping, and  automobile companies, and heavy industry in general, are overjoyed. And so are their money-hungry camp followers.

But how justified is the attack on the IPCC? One tell-tale giveaway is the climate sceptics’ contempt for the actual data in the Indian government’s study, and the impeccable credentials of the Indian scientist, Syed Iqbal Hasnain, and the unholy glee with which they have set about destroying the icons of the anti-global warming movement Nobel Laureates and R K Pachauri, by attributing financial motives. Not only has this no precedent in Nobel history, but coming from oil giants who were, till the other day, sending secret memos to their peers to ‘organise’ town hall meetings against the Waxman Markey bill, this is truly rich fare.

What the Indian ministry of forests and environment paper actually says is that the average retreat of glaciers, which was about five metres a year since the 1840s when records began to be kept, accelerated ‘manifold’ between the 1950s and 1990s. But the retreat slowed down after the mid-90s till, in some of our biggest and best known glaciers such as Gangotri and Siachen, “it has practically come down to standstill during the period 2007-09”.

V K Raina, its author therefore debunked the idea that “most of the glaciers will be gone in 35 to 40 years.” But with the exception of the Siachen glacier, which exhibits clear cyclical tendencies, he has not found a single glacier that has actually advanced, even after 1994. On the contrary, Raina’s study shows that while most glacier snouts  have stopped retreating, glaciers have not stopped losing mass, although they are doing so more slowly than before.

Aerosols deposit
What could have caused the glacier snouts to have stopped retreating? One possibility that Raina mentions but does not elaborate upon is the deposit of dust and black carbon (collectively called aerosols) upon the snow. Till an accumulation of 400 gm per square metre it sharply raises the rate of melting. Between 400 and 600 gm it has no further effect, but when it exceeds 600 gm, it acts as a shield against the sun, and slows down melting.

As there are much thicker coatings of dust and carbon at the lower ends of glaciers this might explain the tendency Raina noticed in several glaciers of their narrowing in the middle to form two distinct parts. The slowdown in the retreat of the snout of glaciers could therefore be a consequence of the very rapid rise of population in the hills, and the desertification caused by overgrazing.

Only more research focussed on the differences between glaciers in heavily populated areas and those in uninhabited ones like Siachen will answer this question definitively. But, meanwhile, relying upon population growth and desertification to prolong their lives. That would be robbing Peter to pay Paul.

Let us now turn to the attacks on the IPCC. Syed Iqbal Hasnain, the source of its alarming quote on the Himalayas is not an egotistical  scientist hungry for his moment in the sun. He was the professor of  glaciology in the school of environmental sciences, Jawaharlal Nehru University in Delhi and a fellow of the prestigious Indian Institute of Technology, Mumbai, and the Delft Technical University, Netherlands.
Between 1995 and 1999 he chaired a working group on Himalayan glaciology within the International Commission on Snow and Ice. He is the author of a book, ‘Himalayan Glaciers: Hydrology and Hydrochemistry’ and several papers and at the moment is conducting a study of the accumulation of black carbon on snow at high altitudes in the Himalayas. Hasnain was speaking only five years after the retreat had reached its peak and only two to three years after the slowdown began — far too soon to say that the trend had changed.

To conclude:  Many, perhaps most but not all, Himalayan glaciers have stopped retreating but are still shrinking. Local influences may be responsible for the recent slowdown. Hasnain’s claim in 1999 was not meretricious. Nor was the IPCC’s acceptance unjustified because in 2003-04, the year before it finalised its report, the slowing down would have been barely perceptible.
Hasnain’s credentials were impeccable, but the IPCC did not rely on his assertion in the ‘New Scientist’ alone, but on innumerable studies that had shown in a uniform trend, punctuated by local anomalies.