Adding features like solar generators or solar water heaters can pay for themselves over a longer term as well. "I think residential is a slam dunk," Levine says. "It's just a matter of applying technology that we already have."

Another area where cities can play a major role in warding off warming is waste management, enhancing efficiency by taking relatively cheap and simple steps such as capturing the latent power in landfills or recycling. "Things like waste recycling or waste minimization actually avoid greenhouse gas generation," says waste management expert Jean Bogner, a lead author of the IPCC report. For instance, making a beverage can from recycled aluminum uses only 5 percent of the energy it would take to create one from scratch. "If you recycle in the case of aluminum, you are talking about a 95 percent savings of energy," says IPCC author Lenny Bernstein, an environmental consultant.

The bottom line: buildings contribute a tremendous amount of GHG emissions whereas garbage produces relatively little (roughly 5 percent, according to the IPCC), but both offer immediate cost-effective remedies for climate change. A key to limiting global warming will be making sure that cities from New York to Addis Ababa implement those changes. "Now is the time to start doing real work," says Ken Livingstone, mayor of London. "Retrofitting our buildings and bringing down our carbon emissions."

2 Comments

1. 1. David M. Clemen 08:02 PM 3/22/08

   I was in Ethiopia in 2002 to help commission an 80 MW hydroelectric facility. I agree that solar power could help in Ethiopia due to their "...13 months of sunshine..."; however, it is too expensive for most of the country/occupants.
   EEPCO (Ethiopian Electric Power Company) has initiated a major hydro program because it not only supplies electric power with zero emissions, but it also provides irrigation for crops and drinking water supplies for the municipalities. When you can solve three problems at once; and supply electricity at a much cheaper rate than possible with solar power, you have a real winner.
   Why do you not discuss hydroelectric energy production when discussing third world country energy sources? Hydroelectric power produces as much electricity as nuclear worldwide (each supply 17% of the world's power supply), and has the ability to furnish flood control, irrigation, drinking water supplies, recreational areas, etc. etc.

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2. 2. Qbriserth 02:42 PM 3/29/08

   This is the first time I have been on this site, and I am impressed to see that America of all places having grand plans. Some of which are already working, I congraduate the authors in communicating to the world that something can be done. (Isaac, Perth, Australia)

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