Water And Oceanography

What is Causing Lake Chad and other Lakes to Shrink and Global Warming

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"What is Causing Lake Chad and other Lakes to Shrink and Global Warming"
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There is no longer controversy about whether the Earth's climate is changing due to Global Warming. The question now is, “how do we prepare for it?”

Scientific communities agree that this decade marks an era of rapid climate change, and that before mid-century (in less than a lifetime), the world can realize irreversible problems of a devastating magnitude. Adding to the severity of Global Warming is an enormous growth of populations, which together, are expected to impact most of the planet by creating mass shortages of food and water.

It's believed that the recent drying up of numerous lakes around the world is evidence of Global Warming, and that a worldwide water shortage looms in the near future.

Global warming is being caused by a buildup of “greenhouse” gases in the atmosphere. Greenhouse gases are necessary, because their job is to absorb the solar radiation that bounces off our planet, keeping it from heading back out into space again.

Greenhouse gases keep Earth's temperatures habitable. But, too many greenhouse gases will capture too much sunlight, causing the planet's temperature to rise. Too few makes the Earth cool off or freeze over. Earth has experienced Global Warming before.

It's believed that 250 million years ago, spewing volcanoes built-up large amounts of Carbon Dioxide and other greenhouse gases in the atmosphere, similar to the way factory smokestacks, and burning fossil fuels (oil, gas, coal) do today. The greenhouse gases warmed up the planet, causing mass extinction, by killing off 90 percent of species on Earth.

The disappearance of many of the world's large lakes should be mankind's alert that something is very awry. Under normal conditions, it may take hundreds, thousands, or even millions of years for a lake to dry up. But recently, they are vanishing at greatly accelerated rates and in alarming numbers.

Some have even vanished overnight, as did Russia's Lake Beloye in 2005. This phenomena is being attributed to Global Warming. It's believed that rising temperatures softened the permafrost, a thick cement-like ice seal on the lake bottom, causing the water to be sucked underground, similar to water draining from a bathtub.

NASA satellite images documented that this is not an isolated occurrence. Warming temperatures in Arctic regions are causing cracks in many permafrost lake bottoms, resulting in an 11 percent decline in the number of lakes between 1973 and 2002. In 2002, at the time of the study, 125 lakes had already been lost.

Glacier regions are warming faster than locations closer to the equator. Glaciers are very important to the planet for their “seasonal” melt, which replenishes fresh water lakes and reservoirs. Many regions, including Asia, India, Peru, parts of Europe, and the United States, have glacier formed lakes.

Warming temperatures will accelerate the melt, and cause problems associated with flooding. Then, once the Glacier has melted, it won't return, and the lakes won't be replenished. It's a startling prediction that the glaciers in the Andes, which supply water to lakes in the tropical Caribbean and South America are expected to disappear as early as 2020.

This will impact 77 million people, cause major destruction to the Amazon Rain Forests, and thereby affect much of the world.

Human activities that put stress on water supplies, and contribute to Global Warming are causing devastating effects. In the central Asian nation of Uzbekistan, salt and sand from the drying Aral Sea (once a large salt lake) is being carried by air currents, dropped on vegetation, and blown into glaciers, making them melt faster.

The lake's destruction was man-made, caused by attempts to divert rivers that fed the lake. The drying has unleashed a toxic dust that is poisoning the air and the people. As wind currents can carry the toxins elsewhere, more regions, even as far away as parts of California may be in it's path. This is called the “grasshopper effect.”

As surface and ocean temperatures rise, colder parts of the world begin to experience ice melt, more rain, and flooding, and coastal areas will see more severe and frequent weather, like hurricanes. Still others, like arid regions, will suffer long droughts.

Lake Chad, which sits at the lower edge of the Sahara desert, is the major water source for the four central African countries of Cameroon, Chad, Niger, and Nigeria. It was once one of the biggest lakes in the world, providing habitat for a diverse species of wildlife, and a stopover for many of the world's migratory birds.

Severe periods of drought since the 1970's and the population's activities have made it a mere fraction of itself, as 95 percent of it has dried up.

Some of the most poverty and disease stricken people in the world live in the Lake Chad area. These people rely heavily on the lake for drinking, fishing, and irrigation. But lake shrinkage, from irrigation, drought (caused by changes to their rainy season) and contamination, has so severely hampered the fish catch, many fisherman have turned to agriculture or animal farming in order to survive.

This makes even more demand for irrigation. Since 1983, irrigation withdraws have quadrupled, and the lake's surrounding countries vie for water rights by diverting the Chari and Logone rivers that feed 95 percent of the water into the lake. Proposed water management projects are expensive, unstable, and will take time.

There are currently around 20 million people who need the dieing Lake Chad in order to survive, and it is estimated that the population will nearly double to 35 million by 2020. Water and food will be so scarce, the region will likely face a tremendous humanitarian disaster.

In the United States, the possibility that Lake Mead could dry up by 2021 is almost an incomprehensible thought. Lake Mead is a man-made reservoir, and along with neighboring Lake Powell, is part of the Colorado River system that supplies water to 25 million people in 7 Southwestern states, including Arizona, Nevada, and California.

Researchers at San Diego's Scripps Institution of Oceanography, give it a 50 percent chance of drying up if water levels can't recover from recent droughts, and water usage continues to climb. There is a 10 percent chance it will run out of drinkable water by 2014 and will drop too low to produce hydroelectric power by 2017.

Lake loss is happening all over the globe. Lake Chapala, Mexico's largest lake has lost more than 80 percent of it's water since the 1970's. Northwest China once had over 4,000 lakes. In the last 20 years it has lost over half of them.

The natural life cycle of lakes in Australia, Russia, Cambodia, Sweden, and many other places are being compromised by Global Warming and human activities. As populations grow so do water demands. Two-thirds of the world's water is used to irrigate agriculture, often by pumping out ground water and by diverting water flows.

Farm waste, sewage, and factory contamination kill fish and makes water undrinkable. Burning fossil fuels creates “Acid Rain,” which travels in the atmosphere, poisoning even remote water sources.

Deforestation of lake shore areas, which speeds erosion and sediment fill in, and destroys ecosystems is contributing to their accelerated demise. These are all man-made causes.

Fresh water lakes are so important to the world, that the implications of what lies ahead is staggering. Great losses of farmland and livestock due to flooding or drought, long power outages, a decline in shipping routes, natural landmarks, and tourism, more wildfires, destruction of ecosystems, death of fish populations, and extinction of wildlife will occur as lakes continue to dry up in a warming world.

Birds, butterflies and other migratory species are already starting to adapt, migrating earlier and further north, or to higher elevations. (60 percent of the planet's lakes are in the northern hemisphere). Mankind will have to adapt too, if he is to survive past the later part of this century.

Climate change is happening. Even if we stopped the smokestacks and car emissions this very day, we cannot undo the greenhouse gases that have built up in the atmosphere for decades. The best we can do is implement immediate strategies to stop continued buildup.

Renewable energy that does not put greenhouse gases into the air, recycling, huge conservation efforts, curbing the growth of populations, and Desalination (a process which removes salt from ocean water to make it drinkable), are our hope for a survivable future. But, leaders of nations and individual people must not wait to make these changes, lest humanity goes the way of the dinosaurs.


















More about this author: Rhonda Hart

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