Friday, September 7, 2007

What 9/11 taught us about the environment

As Hawaii struggles with the environmental impact issues surrounding the Hawaii Superferry, and as we approach the 6th anniversary of the 9/11 terrorist attacks, the two events have an interesting nexus. The PBS series NOVA this past week featured a story called "Dimming the Sun" about climate change. In the 3 days following 9/11, when all the planes were grounded, the scientific community saw an unprecedented opportunity -- to measure the temperature of the earth's atmosphere and to determine what impact airplane vapor trails have, if any, on global warming.

The results were significant. From midday 9/11 to midday 9/14, the nights became cooler and the days became warmer by an average overall range of about 2 degrees F, with the assumption of a net warming. They suggest that airplane contrails do have the capability of increasing temperatures to account for a warming trend in the United States, however, there is on-going debate as to whether we should be concerned. The more significant impact of airplanes on our environment is carbon dioxide emissions rather than vapor trails.

Still, the potential impact is being taken seriously, and NOVA reports that the British government is considering requiring planes to fly at lower altitudes (decreasing condensation) over Great Britain, the effect of which will be fewer contrails in the atmosphere.

The point being, Hawaii is currently focused on the environmental impact of the Superferry. Airline carriers have their environmental impacts as well. All might be well considered within a larger context of the scope of our transportation needs, and the environmental impacts of all the various modes of transportation, in our island eco-system.

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