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In the search for sources of the gases contributing to global warming, a surprising source of methane gas, (one of the more significant gases in that category) turns out to be the emissions coming from both ends of cows, sheep and goats.  It seems that these animals are regular gas factories, as a result of their diet and digestive systems.  Incredibly, on a world-wide basis, these animals account for more greenhouse emissions than all forms of transportation combined, partly because methane has 25 times the global warming effect of carbon dioxide.

The cow shown in the photograph above has been fitted with a sample-collecting bag to trap the gases it emits.  While some are working on ways to change the diet of cow herds, these efforts so far only seem to produce reductions in gas output in the 20% range.  Surprisingly, a much larger reduction could be achieved by replacing beef cattle with kangaroos.  A single cow or steer emits methane that amounts to about 1700 kg (1.88 tons) of carbon dioxide per year.  By comparison, a kangaroo produces only about 2.6 kg (5.7 lb) of carbon dioxide per year. This is only about 1/600th the amount emitted by a cow or steer.  Kangaroos, however, are probably a lot harder to milk.
Climate scientists have used sediment cores from the seafloor to show that the decline in the frequency of ice ages during the last 2 million years is not the result of a reduction in the amount of carbon dioxide (CO2) in the atmosphere during that time.  Ice ages used to occur about every 40,000 years until about 1.2 million years ago.  For the last half-million years, the frequency of ice ages has declined to just once every 100,000 years.  One theory for this change was that the amount of CO2 had declined during that time period.  Until recently, the CO2 content in the atmosphere had been measured by analyzing the gas trapped in bubbles found in ice cores drilled from glaciers, but this data only went back 800,000 years.

Using a new technique, scientists analyzed the chemical makeup of the shells of marine microorganisms to determine the level of acidity in the ocean over the period in question.  The more CO2 in the atmosphere, the more acidic the oceans become.  The results of the analysis showed that the levels of CO2 did not explain the change in ice age periods.  The studies also showed that today's level of CO2 in the atmosphere, above 380 parts per million and rising, has never occurred before during that 2,000,000 year interval.
An increasing rate of melting of the Arctic permafrost in areas around the Arctic Ocean may signal a runaway climate change in the next few years.  The observations of Katey Walter show that the rate of melting, and the corresponding increase in the rate at which methane gas, a serious greenhouse warming contributor, is being released could lead to a "thermal runaway" scenario in which no amount reduction of greenhouse gas emissions would be able to reverse the situation.  As this part of the world warms, the release of huge quantities of carbon which have been locked in the permafrost for millennia could trigger an irreversible warming trend which exceeds man's ability to counter it.  This type of situation is what is known as a positive feedback loop:  the air and soil temperature rise, leading to melting of some of the permafrost and the release of the carbon that had been frozen there. This additional carbon leads to further warming, which leads to additional melting, releasing more carbon, and the cycle continues to grow more destructive with each passing cycle.
If anyone doubts that the actions of Man can have an influence on the Climate, a new study shows that humans began affecting the climate back in the 18th century.  Records indicate that in India and Southern China, in the period around 1850, the monsoon rains were reduced by about 20% compared to the rainfall that had been seen in the early 1700's.  This reduction in rainfall has been linked to the destruction of the forest cover.  These forests, which covered 40-50% of the area were reduced to a cover of only about 5-10% between 1700 and 1850.  This was because the trees were no longer taking moisture from the soil and releasing it into the air.