Climate Change - Glacial Retreat

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.

Related articles by Zemanta

• Melting ice (news.bbc.co.uk)
• The Roof of the World, Melting (kristof.blogs.nytimes.com)
• Study: Shrinking glaciers to spark food shortages (mysanantonio.com)

The Guaraní Aquifer - Ground Water in South America II

Despite containing some of the driest areas on earth in Peru and Northern Chile and large arid zones in the vast expanses of east of the Andes, in Patagonia and in Northeastern Brasil, South America is well endowed with water supplies. Five huge river systems – the Amazon, the streams of the Rio de la Plata estuary, the Orinoco, the Magdalena, the São Francisco – and numerous smaller ones along the western slope of the Andes and the Caribbean and Atlantic Coasts make South America a water rich continent. Unlike Asia and Africa where a large fraction of the water supply is already in use, South America has water resources hardly tapped for human uses other than transportation. Hidrovia, noted in an earlier posting, is mostly a transportation proposal

The Guaraní aquifer is one of the largest known underground water deposits. Some even think it is the largest fresh water body on earth, larger in total volume than either Lake Superior or Lake Baikal! It is estimated to contain more than 35,000 cubic kilometers of water (the estimates on the map above are at the high end of the range) in a basin that stretches from tropical Brasil south into Paraguay, Argentina, and Uruguay with a surface extent of well over a million square kilometers. At present, water from the aquifer directly supplies about 30 million people, though it is estimated that it could sustainably support the water needs of 10 times that many. Outflow from the aquifer supplies some of the water in several major rivers including the Paraná and the Uruguay. Among the major aquifers of the world it is one of the least utilized, and except locally around a few communities using the water, there is little evidence pointing to the draw down and even exhaustion of groundwater familiar in large aquifers elsewhere.

With increasing demand for water throughout the world, there will undoubtedly be increased demand for the water in the Guaraní Aquifer. The booming economy of Brasil has increased water demand for urban uses, industry, and especially for agriculture in the recent past. Much of the Brasilian population lives near the aquifer, and the immense metropolitan area of São Paulo is only a few kilometers from its edge.  As with many large aquifers, much is unknown about the quantities of water and patterns of flow below the surface. A large research project by the IAEA (International Atomic Energy Agency) is attempting to discover more about the aquifer in hopes of improving management as water demands increase. All of the countries are members of Mercosur, the Common Market of the South, and there is an effort to use it as a foundation for management of the aquifer as demands for water increase.

During the Cheney-Bush administration the United States held military exercises in Paraguay, and there was a rumor that Bush or members of its family had purchased 100,000 hectares in the northern part of the landlocked country. While there is no compelling evidence to support the contention, local critics argued that the US was engaged in military exercises in a preliminary move to claim water from the aquifer. That is probably incorrect, at least for now, but the Guaraní is likely to be a major focus in debates about the world's water in the very near future. A documentary film about it is currently in production by the Guarani Project.

Hidrovia and Water in South America I

Evening view of the junction of Rio Iguazú (right) with Río Paraná from Argentinian Bank, Brasil to right and Paraguay left (Ciudad del Este high rises in distant background), 2007

©EOP

Water transportation is not going to be a topic for discussion in the course, nor will wildlife conservation issues be emphasized, but they are both related to human water use. At the moment I am also preparing to lead a course on the Southern Cone of South America where the Paraná and its tributaries are important for transportation, for wildlife, and for water supply. The Paraná is navigable for small ocean going ships upstream as far as the Argentinian city of Corrientes, and its branches can be navigated further upstream into Brasil and Paraguay by shallower draft vessels. Landlocked Paraguay has long been dependent on the river for transportation access, and inland Argentinian cities including Corrientes and Rosario are also dependent on river transportation for access to world markets. More recently the commodity production boom in Brasil has greatly increased transportation demand as that country extends its ecumene into the interior.

The Rio de la Plata river system, including the Paraná its largest single stream, is one of the world's great river systems with a flow second only to the Amazon in the Americas.Its flow comes mainly from rainfall in the humid zones of subtropical and tropical southern Brasil, though it is not an exotic river for there is an excess of precipitation over evapo-transpiration in normal years along much of its length. Several huge hydroelectric projects on the Paraná provide much of the power used by Brasil, Argentina and Paraguay and have converted large segments of its upstream basin into slackwater lakes. As yet the Paraguay, a major tributary to the Paraná and navigable in some years into Brasil, has not been dammed.

A problem for navigation is the uneven flow across the year and from year to year. Hidrovia is a project to even out the flow of the Parana by manipulating water in the Pantanal, the immense marshland on the boundary between Brasil and Bolivia. While the project is apparently moribund at the moment, it is likely to be revived. The problem is the Pantanal is one of the world's great wetlands, and one of the largest still largely untouched by human activity. Known for the diversity and density of its wildlife, conservationists argue that it should be preserved in its current state.

In future postings I shall examine Hidrovia in greater detail and look at other aspects of water availability and use in South America.