The debate regarding the effect of human activity on the climate is heating up while the fear of closing ski resorts as a result of the effect of warming is increasing
Avi Blizovsky
Map of ski resorts that are in danger of closing due to global warming (see news below)
Direct link to this page: https://www.hayadan.org.il/skimelt.html
Humans have warmed the Earth's climate in the last ten thousand years. This is what American scientist William Ruddiman claims. The professor from the University of Virginia says that agriculture has released greenhouse gases into the air and pushed the temperature up by at least one degree Celsius.
This balanced the cooling process that was supposed to result from the reduction in solar radiation reaching the earth at that time. The professor presented his findings to the American Geophysical Union (AGU) which is currently meeting in San Francisco for its annual conference.
On a scale of thousands of years, the earth goes through cycles of hot periods and cold periods driven by changes in the amount of radiation coming from the sun. Prof. Rudiman calculated and found that if the Earth had to behave according to its natural cycle, then it should have been much colder in the last ten thousand years. According to him, humans added greenhouse gases at a rate that canceled out most, if not all, of the natural cooling. Human activity has kept temperatures constant.
rapid heating
The birth and development of agriculture is the key to the continuous change of the nature of the earth and its interrelationships with the atmosphere. "Our ancestors started adding greenhouse gases simply by cutting down trees to make room for agriculture. The concentration of methane - another gas that contributes to the greenhouse - began to increase with the increase in rice cultivation.
Prof. Rudiman, from the Department of Environmental Sciences in Virginia believes that this warming has contributed a whole degree Celsius to the average global temperature for ten thousand years.
This theory is actually negligible among existing theories concerning the climatic changes and it is almost certain that it will arouse a debate among the researchers. However, there is also supporting evidence and it is also consistent with all the knowledge we have about the impact of agriculture today. It also rejects the assertion that more than one degree Celsius has been added in the last hundred years, largely because of our dependence on fossil fuels.
Most scientists believe that the world is warming faster than at any other time in recorded history.
sophisticated ways
Other studies presented at the AGU meeting hypothesize that climatic changes allowed civilization to flourish in southern Mesopotamia, a place considered the birthplace of modern Western society. In northern Mesopotamia, rain-fed agriculture managed to survive for a thousand years and then was brought to a rapid end by a break in the rains 8,200 years ago, says Prof. Harvey Weiss of Yale University. Prof. Weiss told AGU that this sudden drying led to the development of field irrigation, but this was impossible in northern Mesopotamia, because the Euphrates and Tigris rivers, which bordered Mesopotamia, flowed in channels below the level of the agricultural areas. However, irrigation from the rivers was possible in southern Mesopotamia, and this is the reason why great cultures appeared there characterized by art, literature and sophisticated social structures.
Prof. Weiss said that it was a kind of irony that the natural changes in the climate made possible the existence of modern society, when humanity is now changing the climate in ways that could threaten its existence.
For news at the BBC
The good warming of the earth
By Kenneth Chang
The surface of the earth / It is possible that human activity prevented an ice age thousands of years ago
The creation of heat-trapping gases by humans has affected the Earth's climate almost since the beginning of civilization, and this effect prevented the start of an ice age several thousand years ago - this is what Dr. William Rudiman, a retired climate researcher from the University of Virginia, claimed last week.
Most scientists attribute global warming over the past hundred years in part to emissions of carbon dioxide from human activities such as driving cars and manufacturing in factories. At a conference of the American Geophysical Union, held last week in San Francisco, Rudiman said that the influence of humans on the climate began almost 10,000 years ago, when humans stopped hunting and gathering and moved to agriculture. Rudiman also reported his findings in the journal "Climatic Change".
In a review article accompanying the study, Dr. Thomas Crowley of Duke University writes that he was initially surprised by Rudiman's assumption. "But when I started reading," Karoli writes, "I couldn't help but wonder if he might be onto something."
The climate of the last 10,000 years was unusually stable and allowed civilization to flourish. According to Rudiman, this stability originates from the clearing of forests in Europe, China and India for the purpose of planting fields and creating pasture areas. According to him, the carbon dioxide that was released due to the destruction of forests and the methane - also a heat-trapping gas - emitted from the irrigated rice fields in Southeast Asia, captured enough heat to balance expected natural cooling. "The source of stability is the disruption of the natural system," said Rudiman.
The level of carbon dioxide and methane in the atmosphere rises and falls in natural cycles of thousands of years. Both gases reached peak levels at the end of the last ice age, 11 thousand years ago. After that both decreased as expected. The proportion of both gases in the atmosphere should have continued to decrease until today and lead to a decrease in temperature and the beginning of a new ice age 4,000 to 5,000 years ago. But according to Rudiman, the downward trend in the amount of carbon dioxide in the atmosphere reversed 8,000 years ago and the level of the gas began to rise. The decrease in methane levels reversed 5,000 years ago - along with the beginning of growing rice in irrigated fields.
New York Times
Ski resorts will be closed in the future due to global warming
8/12/2003
Zafarir Rinat
Winter sports enthusiasts will find it difficult to pursue their hobby in the future: according to a UN report published last week, the warming of the earth will cause within 50-30 years a decrease in snow and severe damage to well-known ski resorts in Europe (see map), the USA and Australia.
Scientists estimate that in the last 100 years the average temperature on Earth has risen by 0.6 to 1 degrees Celsius, and by 2100 it will rise by another 1.4 to 5.8 degrees. The results of the warming will be felt, among other things, in more and more winters where there is relatively little snow.
Switzerland, which is dominated by ski resorts, will be one of the main victims of this trend. If today only 15% of the ski resorts in the country are defined as "unreliable for skiing" - a reliable resort has seven out of every 10 years, and for at least 100 days, 50-30 centimeters of snow - in the future the rate of unreliable resorts will be 56-37%
The damage to the ski resorts is expected not only on the low slopes: the Alps have glacial areas where skiing takes place throughout the year; Climate experts predict that by 2030, 70% of the glaciers in these regions will disappear. The expected damage to winter sports will result in a loss of 1.6 billion dollars a year in Swiss revenue.
Damages will also be recorded in Austria, where the snow line is expected to rise in another 300-200 meters - which could severely damage the livelihood of villages that provide services related to winter sports; And in Italy, where half of the villages that depend on winter sports lie at an altitude of less than 1,300 meters - therefore most of them will have only a few winters in the future that will allow suitable conditions for skiing or other types of winter sports.
The worst impact outside of Europe is expected in Australia: according to the pessimistic forecast, the average temperature on the continent will rise by 3.4 degrees Celsius by 2070 and there will not be a single ski resort left in the country that can last. Even if the less pessimistic forecasts come true and the rise in temperatures is more moderate, many sites will be shut down.
Damage on a smaller scale is expected in the United States and Canada, on whose sites artificial snow is already widely used - which will enable regular activity at many sites even with increasing warming.
The new UN report was prepared by a team of experts from the Department of Geographical Economics at the University of Zurich, for the "Environmental Protection Program" - a special body on behalf of the UN that deals with environmental conservation and that participates in research that examines the relationship between environmental phenomena and sports.
UN experts have no solutions to prevent the disappearance of snow at low altitudes, and they claim that the ability of ski resorts to survive will depend on how well they adapt to the new conditions. Only sites that can provide convenient transportation to mountains higher than 2,000 meters, by establishing new and expensive infrastructures of roads and cable cars - will be able to last.
The low sites will gradually disappear, and most of the winter sports activities will be done at the high sites. They emphasize that in such a situation, the pressure of surfers on the "high" sites will increase, and it will be necessary to find ways to protect the ecosystem from the crowds of tourists.
Environmentalist - Earth
There is no doubt that global warming is real, say experts from the USA
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