Between 1941 and 2004, most of the 610 meter thick Riggs Glacier in Alaska’s Glacier Bay National Park disappeared. And most of the ice melted away in the Upsalla Glacier, Patagonia, and only the ice blue lake survives — all between 1928 and 2004.

Cut to 2010, the temperature at St Petersburg goes up to forty blistering degrees and forest fires in Russia were unheard of. Even in British Columbia, Vancouver in a recent visit, one encountered temperatures soaring up to almost forty degrees. On Thursday (August 5) an ice island four times the size of Manhattan has broken off from Greenland’s main glaciers — an event not observed in the Arctic in fifty years.

And now, we have a gigantic cloud burst at Leh reducing the picturesque town to rubbles, many lost lives – an event quite unprecedented. These natural disasters are horrid beyond imagination.

One had a back stage role in setting up a large telescope at Hunley, some 15,000 feet above the sea level with Leh as the base camp. Hunley was chosen for its most unusual weather conditions. This is one of the highest desert mountains in the world. Hunley hardly gets any rain, with a sky filled with stars at night and very fierce sun light during the day. The particular weather condition is perfect for watching the sky and observe the drama of the cosmos and its inhabitants at night.

Leh, just 10,000 feet above the sea level has rather similar weather conditions. The rainfall averaged over a period of one year is negligible at Leh.

In recent times though, buildings after buildings have come up at Leh soaking up in abundance the fierce sun light during the day and breathing out the heat to the atmosphere at night raising the local temperature, not that perceptibly but enough to cause imbalance in the environment. The temperature fluctuates quite a bit depending on the season, it even changes from day by day. It is a common experience.

However, even a slight two to three degrees on a global average has a huge impact on the environment. Vast quantities of water vapour get released into the atmosphere, an unusual component in Leh environment. Deforestation worsens the situation.

The average “global” temperature has been on the rise at Leh.

The near desert condition aro­und that area could not have been the standard natural scenario a few thousand years ago. As one drives from Leh to Hunley one comes acr­oss the most hauntingly beautiful landscape, with soil coloured almost crimson, dry with hardly any vegetation. Once in a while the Tibetan deer wanders in. Even a slightly perceptive look will tell your eyes that years ago large chunks of glacier, probably water later, flowed across the mountain ridge -- now completely dried up leaving the clear footprints of the “flow”, reminiscent of what has already happened in the Arctic in more recent times. More or less the same fate changed the great Sahara from an oasis of green to a desert some thousand years ago. All these events, one can make an intelligent guess — have a common link and that is the rise in the temperature on a global scale usually referred to as global warming.

Indeed, the climate of the earth has varied a lot during the billion years or so of its existence. At times, the earth looked like a snow ball or at least a slushball, while at other times tropical animals inhabited the polar region with a stone like look of the Hi­malayas with no ice whatsoever. Even in the roughly hundred thousand years of homo-sapien’s “tenancy” on this earth, ice ages have come and gone. It is only during the last 8,000 years or so, since the beginn­ing of agriculture, situation has been conducive enough to kickstart the industrial revolution around 1780.

As industrialisation progressed, the burning of fossil fuel increased and consequently the carbon dioxide levels started increasing steadily. In the beginning the rise was slow, it took a century and a half to reach the figure 315 ppm (parts per million). Incredibly enough, the characteristic “residence” time of carbon dioxide molecule is about a century — a fact not known or understood by many. Today, that level has come up to 380 ppm and is expected to go up to 450-500 ppm by 2050 if we carry on with business as usual.

With that huge reservoir of carbon dioxide, eventually, the blanket of this gas warms up the earth, usually known as greenhouse effect, to an irreversible point.

This is all man-made, anthropogenic. Unlike the beginning of the agricultural period. Indeed, it has been found that with the rise of the mercury , along with increasing ocean and mountain temperature, the frequency of cyclone or hurricane or rain fall may not change dramatically but it has very strong effects on its severity. Man knows quite a bit by now about hurricane, cyclone but very little about cloud bursts or flash flood.

With the cloud burst at Leh, an ocean of rain drops, not the ordinary drizzle rain drop but something like mini balls of water of perceptible size fell on the hill side, dislodging the structure by the sheer momentum of these “large-sized” drops.

So goes the beauty of Leh, plunged under a mountain of mud while the distant hills of the Himalayas remain only a sad spectator. There are many parameters of the environment involved in this, most of which are just getting familiar to us. But greenhouse effect and global warming play the crucial central role.

Yes, climate change is here with its full fury, just as some do not believe smoking has anything to do with lung cancer, disbelievers of climate change will only help bring the severity of its consequences more dramatically. Time to wake up and take charge.

The writer is a Homi Bhabha professor with Department of Atomic Energy, VEC Centre, Kolkata