Carbon budget shapes Portland's new climate change goals

In his state of the city speech last Friday, Portland Mayor Sam Adams announced the city's new goal to reduce carbon emissions 80 percent below 1990 levels by 2050. That's a huge undertaking, even for Portland, which managed to reduce emissions enough to equal 1990 levels in 2007, but is still short of its goal for 10 percent below 1990 levels by 2010. So the question is, how exactly is the city going to accomplish this?

The Portland Bureau of Planning and Sustainability's formal plan isn't due out for public comment until June, but some of the details have trickled out. The city is basing its plan on a carbon budget for 2050 - basically trying to divvy up emissions allowances from every source - transportation, electricity, home heating, etc, so that it all equals 20 percent of 1990 emissions.

That means fundamentally changing the way the city works, said BPS's deputy director Michael Armstrong. One goal for cutting transportation-related emissions, for example, is to make every destination necessary for daily life, from dentist offices and grocery stores to parks and schools, accessible within a 20-minute walk from home. So city policies such as zoning and parking fees will become much more aggressive to promote denser development.

The city is also considering completely eliminating electricity from the carbon budget, meaning all of the city's electricity needs would be met with renewables. Doing the same for home heating is a bigger challenge, said Armstrong, but they're assessing the possibility for district energy development in some neighborhoods.