Many leaders who gathered for the UN climate summit in Copenhagen believed that market forces—and consumers in particular—would drive the transition to a low-carbon economy. A comforting thought, but I wouldn't count on it just yet. Having co-written The Green Consumer Guide, in 1988, I believe that consumer action can tackle environmental issues effectively. But I fear that anything today's green consumers may do will be swamped by the actions tomorrow of hundreds of millions of their counterparts in emerging markets.

On the plus side, there is evidence that consumers are paying more attention to green issues, including climate change. A few months ago, the National Geographic Society and Canada's GlobeScan research group released the second annual Greendex survey of sustainable consumption patterns across 17 countries. A total of 65 lifestyle choices of consumers are included, covering areas as diverse as energy use, transport, housing, food and product purchases. The headline result was that sustainable consumer behaviour had risen in 13 of the 14 countries surveyed in both 2008 and 2009. Surprisingly, the top-scoring consumers of 2009 are in India, Brazil and China.

But if you were to ask me which recent green consumer-related initiative has excited me most I would point you to the US launch of a new application that runs on Apple's iPhone, allowing users to scan products with their phone fitted with a barcode scanner.

The GoodGuide app helps consumers make on-the-spot decisions. As GoodGuide explains: "Consumers can scan a barcode in the supermarket aisle and see detailed and independently researched ratings for health, environment and social responsibility for over 50,000 products and companies on the phone." In a version of crowdsourcing, GoodGuide aggregates information about which products are scanned most frequently, helping it to prioritise future research.

I don't believe that this product will solve our climate problems, but it will give us a better sense of our environmental footprints, if we are interested enough to look beyond the packaging and the price tag. And the technology will quickly evolve.

John Elkington is co-founder of SustainAbility and Volans (www.volans.com)