In 2007, the Intergovernmental Panel on Climate Change stated with unprecedented confidence that human emissions of greenhouse gases are causing a rise in average annual temperatures across the globe.  Regionally, the King County Climate Action Plan shows that King County generates an estimated 23,000,000 metric tons of carbon dioxide (MTCO2e) annually -- otherwise known as our “carbon footprint”.

Unlike the majority of places in the U.S., most of the greenhouse gas emissions in King County come from transportation.  This is because hydroelectric power leads to a lower contribution of the electric sector to total emissions in our region compared with the national average.  Additionally, other parts of the country have more heavy industry.  

As a result, King County has nearly twice the national average as a percentage of transportation-related emissions, although for highway transportation the Seattle-Tacoma-Bellevue metropolitan area ranks 27 out of 100 metropolitan areas on a per capita footprint basis.  The contribution from residential energy use is also lower than most other metropolitan areas as a benefit of our moderate climate. 

Overall then, our footprint is small then compared to most other U.S. cities.  But it is also true we must do whatever we can, both individually and collectively, to stop global warming. Our ability to reduce transportation-related emissions in the face of growing population will be at the center of climate protection initiatives in this region for years to come.

Since the production of all products and services involves energy use, increased consumption translates into greater emissions. The component of the Consumer Environmental Index for carbon dioxide captures this effect.  There's also all the vehicle miles that go into shopping and the commute to work.  Total vehicle miles traveled in the Puget Sound region has increased about 25% from 1992 to 2006, with people driving 900,000 more miles each weekday in 2006 compared to 2005.  Puget Sounders also rack up our share of air miles travelled.    

It is possible to offset at least some of this growth in consumption through the purchase of greener products.  Unlike other parts of the US, Washington State generates little coal-powered electricity although it does get 10% of its electricity from a coal-fired plant in Centralia.  The bulk of our electricity comes from hydroelectric power.  But transportation is fueled by gasoline, King County’s largest energy source.  Not surprisingly then, transportation is our region’s largest component of greenhouse gas emissions by sector. 

Infrastructure and product use efficiencies matter too for climate protection.  Tighter, more compact development lends itself to greater energy efficiencies, while urban sprawl and reduced forest cover means fewer trees to store or sequester carbon emissions in this region. 

Of particular concern is the disruption to our natural water cycle. The consequence will be more frequent, extreme weather events such as droughts, fires, floods and mudslides, as well as substantial reductions in our snowpack, significant water shortages, rising sea levels, reduced forest cover, poor air quality, and destructive pest infestations.

Snowpack areas that are close to freezing in mid-winter in the Cascades will be most sensitive to warmer temperatures. Based on projected temperature increases, April 1 snowpack could experience a 44 percent loss by the 2040s, and a 58 percent loss by the 2060s.  The reduced snowpack levels will lead to a decrease in water supply as well as lower summer stream flows and higher stream temperatures that negatively impacts salmon habitat.  Since 1992, seven salmon stocks have become extinct in the Puget Sound region and the number of stock considered healthy has declined from 93 to 81. 

The potential economic impacts of all these changes are just now being studied, but early analysis shows substantial costs in areas such fire fighting, water conservation, energy costs, insurance premiums, agricultural losses, public health, and damage from flooding and droughts.

Finally, it is predicted that our region will see an increase in population from people migrating here to escape the effects of climate change in regions where there will be severe water shortages.