Tag Archive | "causes of global warming"

Major Gases Responsible For Global Warming

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The greenhouse effect is a natural process by which the earth keeps itself warm enough for the living organisms to survive. However, due to the human intervention, the level of these greenhouse gases has increased to such an extent that the greenhouse effect is become hazardous for human life.

gases

Greenhouse gases are heat trapping gases formed on earth through natural processes and human activities, which then enter the atmosphere. Here are some of the major gases responsible for the greenhouse effect.

1. Carbon dioxide (CO2)

Carbon dioxide is being emitted in the air constantly as every time you breathe, a tiny amount of CO2 enters the atmosphere. However, this is an extremely small amount as compared to the CO2 produced when wood and fossil fuels such as oil, natural gas, and coal are burnt. Many other industries also produce CO2 as a by product. Although plants get rid of the CO2 present in the air during photosynthesis. With the increase in the fossil fuel combustion and deforestation, atmospheric CO2 has increased greatly. Carbon dioxide is accountable for most of the global warming, and with the ongoing rate, atmospheric CO2 level can almost double as soon as in 2050.

Global Warming: Seasons Now Arrive 2 Days Earlier

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BERKELEY — Not only has the average global temperature increased in the past 50 years, but the hottest day of the year has shifted nearly two days earlier, according to a new study by scientists from the University of California, Berkeley, and Harvard University.

Just as human-generated greenhouse gases appear to the be the cause of global warming, human activity may also be the cause of the shift in the cycle of seasons, according to Alexander R. Stine, a graduate student in UC Berkeley’s Department of Earth and Planetary Science and first author of the report.

"We see 100 years where there is a very natural pattern of variability, and then we see a large departure from that pattern at the same time as global mean temperatures start increasing, which makes us suspect that there’s a human role here," he said.

Although the cause of this seasonal shift – which has occurred over land, but not the ocean – is unclear, the researchers say the shift appears to be related, in part, to a particular pattern of winds that also has been changing over the same time period. This pattern of atmospheric circulation, known as the Northern Annular Mode, is the most important wind pattern for controlling why one winter in the Northern Hemisphere is different from another. The researchers found that the mode also is important in controlling the arrival of the seasons each year.

The Four Seasons

Whatever the cause, Stine said, current Intergovernmental Panel on Climate Change (IPCC) models do not predict this phase shift in the annual temperature cycle.

Details are published in the Jan. 22 issue of the journal Nature.

Temperatures at any given time of the year can be very different on land than over the ocean, Stine said, and a change in the strength and direction of the winds can move a lot of heat from the ocean onto land, which may affect the timing of the seasons. However, this seems to be only a partial explanation, he said, because the relationship between this pattern of circulation and the shift in the timing of the seasons is not strong enough to explain the magnitude of the seasonal shift.

The researchers also found that the difference between summer and winter land temperatures has decreased over the same 50-year period, with winter temperatures warming more than those in summer. They found that in non-tropical regions, winter temperatures over land warmed by 1.8 degrees Celsius and summer temperatures increased by 1 degree. Ocean warming has been somewhat less.

Stine noted that the study limited its focus to non-tropical regions because the seasons are more pronounced outside the tropics.

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