Washblog

Aviation is a major contributor to greenhouse gas emissions and its contribution relative to that of other modes of transportation is rising.  As the Port's new study points out, aircraft emissions at cruise altitude are deposited directly into the upper atmosphere.  The Intergovernmental Panel on Climate Change has noted that emissions at this level have a greater warming effect than those created at the surface.    Methodologies to measure these emissions and their impact, as well as regulation of these emissions, are in the very early stages of development.

In general, aviation emissions are less studied and less regulated than surface emissions. Public accountability for these emissions is lower than for other modes.  Aviation also appears to be, almost universally, left out of intermodal transportation planning.  (See Washblog story, Sustainable Aviation in Cascadia, for further discussion of this in the national and international context.)

The Port of Seattle's inventory, then, represents an advancement in the state of current knowledge and a building block for effective policy action.  It covers ground emissions -- both at the airport and in traffic in and out of the airport; emissions for take off and landing; and emissions for cruise operations above 3,000 feet based on the fuel dispensed at the airport.

The inventory helps to set the context for its findings with an outline of greehouse gas reduction plans on the international, national, regional, state and local level. Plans noted in the outline include the Kyoto Protocol, the Intergovernmental Panel on Climate Change, the US Mayors Climate Protection Agreement (launched by Seattle's Mayor Nickels), the Seattle Climate Action Plan, the King County Climate Plan, the West Coast Regional Governors' Climate Strategy,