People can use the to calculate their carbon footprint and choose carbon-reducing steps from a personalised action plan. They can also compare their actions with those of others around the UK by putting themselves on the Google UK Carbon Footprint Map and joining discussion groups.
The carbon calculator has been built in partnership with the Energy Saving Trust and Carbon Limited RSA, using data from the Department for Environment, Food and Rural Affairs. British Gas and government campaign Act on CO2 are also involved with the project.
The site includes constantly updated sections including user-generated content from BSkyB, project statistics and a carbon footprint news feed.
Google has also created a special version of its personalised homepage, iGoogle, relating to the project.
The carbon footprint map shows information such as predicted future weather under different carbon emission scenarios, recycling rates of local councils, heat map images of famous buildings and where your nearest renewable energy sources are.
Ed Parsons, geospatial technologist at Google, said: "We want to help people find the information they are looking for as quickly as possible and that's why we have launched this project."
Hilary Benn, environment secretary, said: "We have decided to openly share our calculator data with organisations ranging from local authorities and charities to big businesses, to ensure that even more people have the chance to calculate their carbon footprint using the most up-to-date data and calculations."