Footprint as Yardstick
We touch a mere fraction of what we use. Without realizing it, we feed huge appetites with resources from distant places. The chip we eat comes from a chain of activities. Tractors till, apply petro-fertilizers, and harvest. Irrigating water gets heaved over hills and pumped from below. Grain is transported, milled, baked and packaged – and transported again to warehouse and store. That’s no small chip.
We each have an ecological footprint considerably larger than what we use, touch, or occupy. And we are consuming resources at an accelerating rate. The Global Carbon Project estimates 2010 American greenhouse gas production to be 1.5 billion tons of carbon in 2010 – and increasing.
Now consider the multitude of things needed to support a region –from city center past suburbs into farmlands to the receeding edges of nature. Enormous webs of resources flow to support our lives. We construct buildings from materials extracted, processed, distributed, and assembled. We heat and cool buildings. We move water long distances. And we move around in cars and trucks – a lot.
The average household drives about 20,000 miles per year – equivalent to a thousand gallons of gas – 20,000 pounds of carbon dioxide – or 10 tons of greenhouse gas per household per year.
We may think that we occupy only our house but we inhabit a much bigger landscape: a share of the places where we work and shop; a share of our highways; and a share of faraway places that we never see – the farmlands that feed, the forests and mines that provide, and the oil that warms and propels us.
Accelerating in Reverse
In spite of awareness of environmental issues and increasing alarm over global warming, we consume more resources than ever – and we consume them at an accelerating rate. Global consumption of natural resources could triple to 140 billion tons a year by 2050 unless consumer nations take drastic steps. A report by the United Nations Environmental Program warns that “the prospect of much higher resource consumption levels is far beyond what is likely sustainable.”
Consumption has grown much faster than population, which has grow at an extraordinary rate. The world’s population has doubled in the last fifty years (passing 7 billion in 2011) and will likely double again by century’s end. The greatest per-capita consumption has been in America – 30 tons of resources per person each year. Europeans consume half of that, and the global average is half again – about 8 tons per person.
Interestingly, the UN report also found that developed countries with relatively low population densities, like the US and Australia, consume resources at twice the per capita rate as the average for more urban countries – even though income and material comfort do not differ substantially. Low population densities were found to increase the materials and fuels used to propel cars, heat homes and offices, and expand infrastructure, among other things.
For the roughly one billion people who live in the developed world, demand for resources continues to expand. If China and India were to “catch up” to European levels (and they are heading in this direction), global consumption of natural resources would triple.
The biggest challenge lies at home. Developed nations consume over 30 times the energy per capita as the developing world – and North America consumes the most. The U.S. and Canada account for about 5% of the global population, yet consume over 25% of the world’s energy and generate the same portion of global emissions. Estimates from the Global Carbon Project put American greenhouse gas production near 1.5 billion tons of carbon in 2010 – and increasing.
The UN report says that by 2050, “humanity could devour an estimated 140 billion tons of minerals, ores, fossil fuels and biomass per year – three times its current appetite – unless the economic growth rate is ‘decoupled’ from the rate of natural resource consumption.”
Giving Urbanism Its Due
Spatial efficiency – efficient urban land use and transportation — provides an effective ways to reverse our escalating thirst for resources and alter our collision course with climate change. In his book, Green Metropolis, David Owen argues that density, more than any other factor, is the key to sustainability. Some academics are more circumspect and point to the importance of transit, complementary land uses, and walkable routes — but density makes these things possible.
Livable density needs to be a shared aspiration. Says Margaret Wente of the Toronto Globe and Mail, “Never mind your recycling, your solar panels or your righteous compost heaps. If you want to cut your carbon footprint, move downtown and throw your garbage down the chute… Manhattanites consume 70 per cent less than the North American average…By comparison, Vermonters – who regard themselves as dedicated environmentalists – are carbon hogs.”
What makes high-density urban places so green? For one thing, homes and businesses are more efficient to heat and cool. Detached single-family houses have expose greater areas of external walls and roofs, and so require more indoor heating in winter and cooling in summer compared with townhouses (attached dwellings) or apartments (attached and stacked dwellings). One neighbor’s apartment or condominium helps to heat adjacent dwellings, and vice versa.
Dense urban places also come with compact infrastructure. Housing at lower densities is spread out and requires more infrastructure per dwelling: more roads, more pipes, more wires. And infrastructure is not a one-time cost. Pipes must be maintained and replaced over time.
Urban residents and workers also rely less on their cars than their suburban counterparts, and generate far less climate-warming carbon. Walk-to conveniences are more available with urban density, as is frequent transit service. Households near transit generate half the greenhouse gas as the regional average. Indeed, ”households in central business districts produce the least emissions of all. …Chicago’s central business district produce 78 percent less greenhouse gas emissions per household.”
Urban dwellers have a much smaller environmental footprint than other people, and it’s time we gave urban places their due. High-density downtowns and urban centers hold special importance, as they significantly outperform other urban and transit-oriented place types –a truth taken up in future articles.
“Density is green…”, notes Witold Rybczynski, a hard-nosed academic, in “Home Truths” (Atlantic Monthly, October 2009). “[A] solar-heated house in the burbs is still a house in the burbs, and if you have to drive to it, even in a Prius, it’s hardly green …. Being truly green means returning to the kinds of dense cities and [compact transit-oriented] suburbs America built in the first half of the 20th century.”
This means changing how we build new places and how we allow our communities to evolve. While many people hold outdated perceptions of dense urban places as overcrowded, crime ridden, and polluted, our ability to deliver clean, inviting, healthful, and secure urban places has never been better.
 UN Environment Program, “Decoupling Rate of Resource Consumption from Economic Growth Rate — Europe Presents a Mixed Picture,” May 2011, http://www.unep.org/resourcepanel/metals_recycling/files/pdf/decoupling_press_release_for_Europe_green_week_May_2011.pdf  Jared Diamond, “Wat’s Your Consumption Factor,” NY Times, 2008, http://www.nytimes.com/2008/01/02/opinion/02diamond.html?pagewanted=all Margaret Wente, “Living In a Greenhood,” Globe & Mail, http://www.theglobeandmail.com/news/opinions/living -in-a-green-hood/article131 .  Robert Steuteville, Warming Up to Smart Growth, New Urban News, October-November 2007.