by Dennis Markatos-Soriano

As world leaders gather in Copenhagen to negotiate international strategy to lower global greenhouse emissions, I’d like to share a vision for part of the solution. Greenways and other improvements in bicycling and pedestrian infrastructure can make make a huge impact lowering emissions in the coming decade. Some economists and politicians who drag their feet regarding climate action complain that lowering emissions could come with a difficult price tag. But at least half of Obama’s 2020 goal can be achieved alongside large savings if we seize the opportunity to increase our use of renewable human power for transportation.

In 2009, US greenhouse gas emissions are ~10% above the goal Obama and the House have set for US emissions in 2020 (17% below 2005 levels). So, how do we lower pollution levels in the 2010s?

Transforming our Transportation System from Polluter to Solution

Transportation is currently one of the biggest polluting sectors, accounting for ~28% of US greenhouse gas emissions (US EIA, 2008). Carbon dioxide-spewing cars, trucks, and planes make up most of our national means of transportation. According to a recent study, only ~12% of Americans utilize active transportation regularly today (9% walk, 1% bike, and 2% take the bus or train). By increasing the bicycling and walking share by just 12.5% per year in the decade to come, we can achieve an active transportation share of more than 36% in 2020.

Such an increase in walking and cycling would cut transportation-related greenhouse gas emissions by over 20%, translating into a >5% drop in total US emissions. That’s more than half the goal Obama is aiming for over the next 11 years, and it comes with serious savings rather than costs. The shift would lower our need to import expensive oil by 25% or more than $60 billion per year (based on $70/barrel oil this would cut our trade deficit by more than 10% from 2009 levels). And by reducing demand for oil, it could help prevent a huge spike in oil prices in the 2010s as oil production becomes more difficult from hard-to-reach sites such as deep offshore fields and polar regions.

A 36% share for active transportation is not far-fetched, since countries such as The Netherlands and Sweden already enjoy 50-65% shares. And the health benefits from more active transportation would help keep health care costs from rising so quickly in the future.

There are some investments necessary to make this transition a smooth one. We need to foster more respect between drivers, cyclists, and pedestrians. And we need to improve cycling and walking infrastructure — building greenways so that non-motorized users have a safe, accessible route without competition with dangerous cars and trucks.

The East Coast Greenway is a perfect example of a transportation corridor that is vital to achieving a 36% active transport share. By connecting neighborhoods to schools, work, and play within cities and between cities, this developing 3,000-mile greenway makes everyday use and long-distance travel achievable by everyone from children to seniors. Where financing is lacking for greenways, we are incorporating low-cost but high-impact improvements in bicycling infrastructure such as bike lanes and signage to achieve the safest route possible in the near-term. And we look forward to working with our friends at the Alliance for Biking & Walking and elsewhere to make this vision one that communities and regions all over the US and beyond can embrace.

While efficiency, solar, and wind power are poised to provide the remaining emissions reduction, an increase in the use of our own renewable muscles can help stabilize our global climate in the decade to come. Achieving emissions reductions never felt so good!

Onwards in the Sustainable Energy Transition-

Based on my estimates that US greenhouse gas emissions will fall in 2008 by more than 1.5% (derived from US EIA Short Term Energy Outlook data), 2008 emissions are ~14% higher than in 1990 (6.16 Gt net carbon dioxide equivalent emissions vs. 5.41 Gt). To reduce emissions to the 5.41 Gt level in 2020 we will need to reduce emissions an average of 1.1% per year. Obama/Biden and McCain/Palin, please keep that number in mind. We can make the sustainable energy transition a relatively smooth one by starting with a 1.1% per year reduction in 2009. This is a big change from the 1990s when our emissions grew ~1.6% annually, but in line with continued progress in the 2000s since our emissions have essentially flat-lined over the last eight years (thanks largely to higher fossil fuel prices).

What would such reduction look like? There are many routes to -1.1%, but a strategy that co-mitigates our dependence on foreign oil would focus on lowering oil consumption. A scenario that seems plausible would be to reduce oil demand by 2% per year, coal by .5% per year, and to allow only tiny growth in natural gas use of .2% annually. By 2020, such oil demand reduction would free us from our current dependence on precarious imports from Mexico, Norway and Russia (geologically declining production) as well as Venezuela and Iraq (where politics and above-ground factors threaten production). It would require an acceleration in fuel efficiency progress (gaining market share for plug-in hybrid electric vehicles along with improvements in bike/ped and transit infrastructure should do the trick). Filling the gaps of lower oil and coal consumption would be a mix of efficiency and wind, solar and geothermal energy substitutes. Other scenarios that would work include faster reductions in oil consumption (this year we reduced demand by more than twice the 2% rate) or allowing coal to grow but making it CCS coal (where the carbon is captured and stored — this technology may be available by the second presidential term or soon afterward). Success at the end of the first term would put US emissions at ~5.95 Gt carbon dioxide equivalent in 2012 and then ~5.7 Gt by the (potential) second term finale in 2016.

In sum, the sustainable energy transition does not have to be a scary prospect for the next president. It can be started by reducing greenhouse gas emissions by just 1.1% per year (a rate slower than this year’s 1.5+%) and doing so can simultaneously help solve our crippling dependence on foreign oil, create jobs in renewables and efficiency, and put our economy in the enviable position of driving global technological progress in the multi-trillion dollar energy sector. Getting started in 2009 helps provide some insurance in case further study and experience shows that NASA scientist Jim Hansen is right that we need to keep GHG concentrations below 450 parts per million (from today’s ~385 ppm) to prevent runaway melting of Greenland and western Antarctica in the decades ahead.