Receding glacier, Upper Joffre Lake, British Columbia, Canada
©EOP
Any discussion of world water supplies over the next century must take into account climate change or what is frequently termed "global warming." The scientific consensus has long since concluded that an increase in global temperatures of several degrees over the next century is nearly certain. The only remaining debate is on how great and how fast the warming will be. That is an important debate, but a little outside our purview. What is important is the impact of increased temperatures on world water supplies. The worst case scenarios for that issue are, to use a very bad pun, chilling indeed.
One early sign of the increase in global temperatures is the recession of glacial ice in the Northern Hemisphere and of mountain glaciers in tropical areas. Glaciers are an important part of the water supply equation as well as a key variable in world climates. Glacial ice acts as a natural reservoir helping to keep runoff in streams constant over the year and from wet years to dry ones. Many perennial streams would run dry for several months a year, and for several years in succession in a severe drought, were it not for glacial melt. Exotic rivers in North America and Asia depend on glacial melt for a sizable part of their flow. The disappearing glaciers of the Rockies are major suppliers of water to the great American Rivers of the west. As a sad example, Glacier National Park is rapidly loosing its namesake features and may have no glacial ice in less than a century. In the Coast Range of British Columbia many glaciers are rapidly melting, like the one feeding Joffre Lakes, one of the most stunning sets of glacial lakes in the world. Not long ago that glacier reached the water of the upper lake. Now the melting glacier is more than 100 meters higher than the lake surface.
Highland glaciers are found in several tropical areas where there is clear evidence of rapid melting. Much of highland tropical South America, including populated parts of Ecuador, Peru, and Bolivia, has permanent streams only because of the water released when glaciers in the high mountains melt. Urban water supplies and irrigation are dependent on that water, for the region is characterized by a division between a wet season and a dry season. There is disturbing evidence of glacial retreat in that area as there is in New Guinea. Kilimanjaro has one of the few glaciers in Africa, and the debate is not if the glacier will disappear but when with the best guess being in about 10 years.
Outside the tropics there is rapid glacial melting in the Himalaya. An unfortunate error in a major climate report concerning glacial melting in the Himalayas has been used as "evidence" by those opposed to the idea of global warming, persons who believe, against all evidence, that global warming is a myth being perpetrated by greedy scientists to get more research funding. The elected Attorney General of the antediluvian Commonwealth of ole Virginny is among those anti-scientific Luddites. Almost all of them are slavishly repeating the propaganda generated by the coal and petroleum industry, an industry which does not want to have any limits placed on coal and oil consumption, the major source of the most important greenhouse gas carbon dioxide. It is clear the glaciers are less important as sources of water in major Asian rivers than the report indicated, and the rate of melting is slower than the alarmist information in the report. But glacial melt in the world's highest mountains is crucial to the flow of the Indus and significant in several other streams. The retreat of those glaciers portends catastrophe in an area where water supplies are already seen as inadequate to meet increasing demands.
