Toronto's mayor on Tuesday launched an initiative to help residents fight global climate change as officials from major cities met in New York City for an environmental summit.

The Zerofootprint Toronto project, launched during the C40 Large Cities conference, combines aspects of social networking websites such as Facebook with an environmental footprint calculator.

The tool lets users chart their ecological impact through different aspects of their lives such as transportation, eating habits, household and office activities and waste habits. They can then compare and contrast their scores with friends who have also completed the assessment.

The collective data would eventually be used by cities to develop environmental policies and programs.

But the city and the system's creators — Toronto-based non-profit organization Zerofootprint Inc. and San Jose, Calif.-based business intelligence firm Business Objects Corp. — also hope that people will use the system to come up with their own eco-friendly initiatives and challenge each other to lower their environmental footprints.

"Climate change is the issue of our time and it's up to all of us to do our part to minimize the impact of day-to-day activities," Toronto Mayor David Miller said. "Zerofootprint Toronto is going to help make my city not only one of the greenest on the planet, but one of the most innovative, as well."

Miller challenged the other mayors at the C40 conference to follow Toronto's lead and add launch their own Zerofootprint programs.

Zerofootprint Toronto will be deployed in two phases. First, City of Toronto employees will be encouraged to create their own environmental profiles, and then the service will be opened to all Toronto residents.

"We all want to do the right thing," said Bernard Liautaud, founder of Business Objects. "The place to start is by measuring the size of the problem and the changes we make. The business intelligence features of this platform will allow people to see exactly what will happen if they — and others like them — change their day-to-day habits."