From EurekAlert Earth Sciences Feed:
"Ice cores drilled last year from the summit of a Himalayan ice field lack the distinctive radioactive signals that mark virtually every other ice core retrieved worldwide. That missing radioactivity, originating as fallout from atmospheric nuclear tests during the 1950s and 1960s, routinely provides researchers with a benchmark against which they can gauge how much new ice has accumulated on a glacier or ice field."
What that means is that Himalayan ice fields are melting away rapidly, so rapidly that the characteristic signal of the 1950's atomic tests has been literally washed away with the melting ice. Much of the Indo-Gangetic plains depends upon glacial meltwater as a source of freshwater that feeds the massive north Indian rivers. If that supply dwindles then water shortages loom ahead. How big is India's water problem. A recent report released by the planning commission has this assessment:
“Currently, total water use (including ground water) is 634 BCM (billion cubic metres), of which 83% is for irrigation. The demand for water is projected to grow to 813 BCM by 2025 and 1447 BCM by 2050, against utilisable quantum of 1123 BCM – 690 BCM from surface water and 433 BCM from ground water. Clearly, the overall demand will outstrip availability in another 35 to 40 years, while ground water in particular will come under even greater pressure in the intervening years.”
So we are headed for a shortfall. The planning commission report provides several recommendations for narrowing the deficit including, artificial recharge of groundwater, extra storage of surface water, and improved efficiency of groundwater use by changes in groundwater law. The troubling part of the report is that it makes no mention of climate change and what effects melting glaciers, erratic monsoons, increase in frequency of droughts, all the expected fall outs of global warming may have on water availability. Has the utilizable quantum of 1123 BCM – 690 BCM from surface water and 433 BCM from ground water been calculated taking into account the expected fall in supply due to shrinking glaciers and erratic monsoons? If the pattern of rainfall changes from a slow steady fall to infrequent high intensity rains, how will that affect groundwater recharge? With glacier shrinking, the surface water availability will increase in the short term but decrease over the medium to long term. Has that been factored in? If rainfall pattern changes over large areas to shorter high intensity pattern, how should we best utilize the increased surface water flows? I did not read the entire report, but did read the conclusions and also did a word search for the terms melting / shrinking glaciers, global warming, climate change and came up with zilch. Sounds like the report assumes unchanging conditions that control water availability.
There already have been accusations that the government has massively overestimated the available water today. Though these new estimates have also been criticized (water debate), any planning commission report which may influence water use policy that does not take into account the changing water availability scenario due to climate change is cause for major concern.
Hello,
ReplyDeleteI had no idea that most of the ice cores retrieved around the world had unmistakable radio activity markers resulting from the nuclear testing of 50s & 60s. Did this radio activity pass from the testing grounds into the surrounding atmosphere / water vapour and then travelled to other regions to deposit there in the form of snow? If so, then it may have precipitated in the form of rains elsewhere. Were such radio active rains detected then? I do not know where & how extensively the core sampling was done in the Himalaya, but is it possible that radio-activity bearing snow may not have reached some parts of the world? Or is there irrefutable evidence to force a conclusion that radio activity bearing snow layer has melted and already washed away?
Another side of Climate change is its Geo-political impact. I heard on TED Talk by Larry Brilliant - no climate scientist - following points :
1. 70% of Bangladesh is hardly 5 feet above mean sea level.
2. Even if the GHG production is held constant at today's levels, many parts of Bangladesh will be inundated permanently with sea water within the next decade.
3. Consequently, over 20 million people will flee into India.
You can imagine the kind of strain that would put on the fragile fabric of North-East. The scenario is unmistakably nightmarish. If above forecast is true, then its no more a possibility but a certainty. Something we should start talking about now and find solutions rather than let the disaster strike us unprepared.
Cheers / Sadanand.
***********
Hi Sadanand-
Yes it is a fallout recognizable everywhere on earth from the polar ice to tropical glaciers. Radioactive rains where also noticed in the early years. There is another type of evidence of the global reach of these tests. Corals all over the world show the presence of bomb radiocarbon in their skeletons which shows that the fallout was quickly incorporated into the worlds oceans.The same with tree growth rings which show the presence of bomb radiocarbon after the tests. In 2000 scientists drilling into ice at Kilimanjaro discovered the typical radioactive signal at 1.8 metre depth. When they revisited that site in 2006, that layer of ice had vanished. The current drilling in the Himalyas was undertaken at around 19,000 feet where it snows substantially and where this signal should have been preserved at some depth. But it appear that melting is outpacing new accumulation of snow.
Regarding Bangladesh I agree the situation is scary. And don't forget out own low lying areas in West Bengal and the deltas of Mahanadi, Godavari, Krishna and Cauvery. There is a danger of significant displacement within India as well.
cheers
suvrat