Energy Imbalance Warming Earths Oceans |
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Written by spacetravel.org
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Monday, 09 May 2005 22:11 |
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The Earths oceans are warming up because the Earth is absorbing more energy from the Sun than it is emitting back into space. The excess energy absorbed, according to a computer model developed by Jim Hansen, director of NASAs Goddard Institute for Space Studies in New York, comes to 0.85 watts for every square meter of the Earths surface, equivalent to the output of half a million 1000-megawatt power stations or 7 trillion 60-watt lightbulbs. Hansen has used real-world data to verify the data provided by the model. The computer model suggests that the heat content of the oceans should have increased by about 6 watt-years per square meter over the past ten years. This agrees with measurements taken by other research teams.
The energy imbalance is mostly caused by the build-up of greenhouse gases in the atmosphere. These gases trap infrared radiation and prevent it from dissipating into space. There is a time lag between atmospheric warming and the rise in ocean temperatures, because it takes decades to warm the oceans from the surface down. Hansens model shows that, whether or not more greenhouse gases are added to the atmosphere, the Earth should experience about 0.6° of global warming, half of it probably in the next 30 to 40 years, and the rest over succeeding decades. This is the same amount of warming that occurred between 1880 and 2003.
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