Cities Racing Against Global Warming

We all love rankings. Who's up? Who's down? What would change the picture?

Today, the Brookings Institution -- a think tank -- released a first-of-a-kind ranking (full-disclosure, I was a reviewer): They rated the 100 largest U.S. regions based on their carbon footprints (since carbon dioxide is the most voluminous by far of the global warming pollutants). Media outlets across the country, as well as the AP, have reported on the study.

There are some surprising results. The top ten cities are:

  • Honolulu (HI)
  • Los Angeles-Long Beach-Santa Ana (CA)
  • Portland-Vancouver-Beaverton (OR-WA)
  • New York-Northern New Jersey-Long Island (NY-NJ-PA)
  • Boise City-Nampa (ID)
  • Seattle-Tacoma-Bellevue (WA)
  • San Jose-Sunnyvale-Santa Clara (CA)
  • San Francisco-Oakland-Fremont (CA)
  • El Paso (TX)
  • San Diego-Carlsbad-San Marcos (CA)

And the bottom ten:

  • Knoxville (TN)
  • Harrisburg-Carlisle (PA)
  • Oklahoma City (OK)
  • St. Louis (MO-IL)
  • Nashville-Davidson-Murfreesboro (TN)
  • Louisville (KY-IN)
  • Toledo (OH)
  • Cincinnati-Middletown (OH-KY-IN)
  • Indianapolis (IN)
  • Lexington-Fayette (KY)

The first thing that jumps out is that seven of the top ten are on the West Coast, with four from California alone. In the bottom ten, three are at least partly in Kentucky and two in Tennessee. My home region of Washington (D.C.), which is south of the Mason-Dixon line, ranks a sad 89th. So these lists seem to pit the West against the South. What's going on?

When getting under the hood of rankings, the first thing you look for is what was measured. In this case, the time span covered was 2000-2005 with focus on passenger and freight transportation and energy consumption from residential buildings. As the Brookings researchers candidly admit, this omits about half the picture: Commercial buildings, industry and other transportation modes (such as planes and transit). On the other hand, the rankings provide a fair indicator of energy use for transportation and electricity, energy-efficiency as well as dependence on fossil fuels (i.e., coal, oil, natural gas).

What are the overall findings?

  1. Large regions stack up pretty well in terms of per capita emissions. These regions account for two-thirds of U.S. population but only 56 percent of emissions from highway transportation and residential buildings in 2005.
  2. Carbon emissions from these sectors are also growing slower than the national average in these major metro areas: From 2000-2005, they grew 7.5 percent vs. the national rise of 9.1 percent.
  3. There are big variations in per capita emissions among these areas. The biggest contrast is Lexington-Honolulu, where an average resident in the former is responsible for 2.5 times as much carbon emissions as the latter (in transportation alone). Notably, the biggest per capita emitters are for the most part east of the Mississippi (with many in the South, as noted above), with Oklahoma City (high-emitter) and New York City (low-emitter) standing out as exceptions.
  4. Development patterns and rail transit access matter. Compact, smart-growth development and the existence of rail transit are decent predictors of a city's ranking.

The report ends with a host of policy recommendations. This is where the relevance to Congress becomes clear. Cities can't move up this ranking -- which I hope Brookings will revisit regularly to benchmark progress by cities -- without fundamental changes in federal policy.

The two big bills on the table are the Climate Security Act and the 2009 renewal of federal transportation policy. Presidents and legislators must shape those two policies, which will allocate hundreds of billions of public investment to various purposes, so that they help boost the efforts of cities to tackle global warming.