San Francisco has come top out of 27 major North American cities for its environmental performance and green policies, according to a new study.

The US and Canada Green City Index is a study conducted by the Economist Intelligence Unit (EIU) and commissioned by Siemens, which takes into account nine different categories.

These are: CO2 emissions, energy, land use, buildings, transport, water, waste, air quality and environmental governance.

These are then analysed according to different indicators such as consumption of water and electricity per person, recycling rate, use of public transport, and CO2 reduction targets.

Eric Spiegel, president and CEO of Siemens Corp, said: "The Green Cities Index demonstrates that America’s cities are the driving force behind the nation’s sustainability efforts.

"Despite the fact that we do not have a federal climate policy in the United States — and no federal carbon standard — 21 of the 27 cities in the index have already set their own carbon reduction targets.

"Cities are creating comprehensive sustainability plans, utilising current technology and proving every day that we don’t have to wait to create a more sustainable future."

San Francisco did anything but wait. As far back as 2007 they became the first US city to ban plastic shopping bags at major supermarket chains and chemists (or pharmacies if you prefer).

And in 2009 they introduced a three bin system (not dissimilar to some UK councils), blue for recyclables, green for compostables, and black for your standard old rubbish (sorry, garbage).

Since the scheme was introduced SF has managed to keep 77% of discarded materials out of landfill sites, and in the long run they are aiming for 90%.

If you’re wondering how London would do... well, the European Green City Index was compiled in 2009, and we came 11th, with Copenhagen taking the top spot.

[Image: Simon Hickson]