From A World To Win News Service

Hurricanes, climate change and global warming

Part 3: How Dangerous is Global Warming?

Revolution #031, January 22, 2006, posted at

November 28 2005. A World to Win News Service. While the U.S. government has insisted that global warming doesn't exist, most scientists are convinced otherwise. Some researchers say global warming was a major factor in the deadly series of hurricanes (as the violent tropical storms or cyclones that hit the Americas are called) that struck the Caribbean, Central America and the U.S. recently. At the Montreal international summit on climate change , the first such meeting since the 1997 Kyoto summit, the U.S. continued to refuse to recognize the dangers or even the existence of global warming, which an attending UK scientist declared is as perilous to the future of humanity as weapons of mass destruction. Observers at the opening of the Montreal meeting of 190 countries had little hope that it would make real progress in achieving international agreements to limit greenhouse gas emissions, the main factor in the rapid rise in world temperatures. Even though the targets for reducing greenhouse gas emissions agreed to at Kyoto are criminally inadequate (the goal is to reduce emissions to 5 percent below the 1990 level by 2012), so far actual emissions have increased, not decreased even the European Union, which supported Kyoto, has failed to meet its target. What is the link between global warming and tropical storms? What are the causes of global warming? To what extent is global warming caused by human activity, and what can be done about it? How dangerous is global warming? Why do the rulers of the U.S. and other major powers refuse to take serious action even as disaster stares mankind in the face? These questions are addressed in this article, which is being run in five parts. See earlier issues for:

Part 1: Natural Climate Changes
Part 2: Man-made Climate Changes

Data provided by the Intergovernmental Panel on Climate Change (IPCC) suggests that the average sea level is on the rise as global warming heats up ocean water, making it expand, and melts glaciers and the huge ice sheets covering Greenland and Antarctica. In general, it shows that over the last 100 years, the global sea level has risen by about 4 to 14 cm. The diagram below shows sea-level changes measured on the Dutch, German and Polish coastlines.

Most scientists believe the rise in temperature, sea level rise, heavy rainfall, flooding in some areas, drought and wildfires in other regions, are a prelude to abrupt changes in the Earth's climate. Based on the IPCC models, an increase of between 20 cm and 88 cm in sea level is predicted by the end of the 21st century. Temperature increase is predicted to have relatively little effect on sea-level rise in the first half of the 21st century, because it takes a lot of initial energy to effect any noticeable change in the ocean-ice-atmosphere climate system. However, if the ice sheets were to melt completely, their contribution to sea-level rise would be as follows: mountain glaciers = 0.3 metres, West Antarctic Ice Sheet = 8.5 metres, Greenland = 7 metres, East Antarctic Ice Sheet = 65 metres. The total sea-level rise would be 80.8 metres - a situation human society as a whole and no nation no matter how rich is prepared to deal with effectively.

The Earth's permafrost (permanently frozen ground in the Arctic regions) is another sleeping giant whose awakening would cause abrupt climate changes. The more than two billion hectares of the Earth's surface that is under permafrost is more sensitive to temperature rise than any other area. For example, in Fairbanks, Alaska, where roads, buildings and lawns have disturbed permafrost, much of it is already thawing. The ground underneath is giving way. Houses are falling apart and large holes in the roads make constant repairs necessary. The effects on the Russian arctic are even more dramatic. If the permafrost continues to thaw, organic material that has been frozen for thousands of years will break down, giving off carbon dioxide and/or methane, which is an even more powerful greenhouse gas. The carbon stored in the world's permafrost, estimated as high as 450 billion tons, if and when released, could easily set off an unprecedented chain reaction with a domino effect on global warming.

An equally important and imminent danger of abrupt climate change has to do with deep-ocean currents (also called thermohaline circulation). The Gulf Stream carries warm and salty surface water from the Gulf of Mexico all the way across the Atlantic up to the Nordic seas. It has been calculated that the Gulf Stream in the Atlantic, for instance, delivers 27,000 times the energy of all Britain's power stations put together. If ice sheet and glacier melt put enough fresh water in Arctic water, the Gulf Stream will shut off due to the resulting equilibrium in the salt content and temperature of the water in the Gulf and the North Atlantic. A shutoff or slowdown in deep-ocean circulation would cause a sudden climatic shift in the UK and Western Europe, with short summers and very cold winters, similar to the climate in Moscow, which is not much further north than Manchester, even though the overall trend worldwide would be toward warmer weather. Similar changes would also wreak havoc with agriculture, not to mention people's daily lives, in other parts of the globe.

Gas hydrates tsunamis are an even more dangerous phenomenon-- perhaps the one that most worries scientists. Gas hydrates are gases (carbon dioxide and especially most commonly methane) trapped in an ice-like form under sea beds and lakes. There are 10,000 giga tons of gas hydrates stored beneath the Earth, compared with only 180 giga tons of carbon dioxide in the atmosphere. There is clear evidence that in the past violent gas hydrate releases have caused massive slumping of the continental shelf, thus setting off tsunamis. About 8000 years ago, a 15-metre tsunami wiped out many Scottish coastal villages.

To be continued.

NEXT WEEK - Part 4: What Is To Be Done?

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