The partnership between the former US president and the large cities climate leadership group - an alliance of Rome, London, Mexico City, Los Angeles and other big cities that have pledged to cut greenhouse gas emissions - aims to reduce the pollutants that contribute to global warming.

 

Clinton said: "It no longer makes sense for us to debate whether or not the Earth is warming at an alarming rate, and it doesn't make sense for us to sit back and wait for others to act.

 

"The partnership ... will take practical and, most importantly, measurable steps toward helping to slow down global warming, and by taking this approach I think we can make a big difference."

 

Ken Livingston, the mayor of London and chair of the group, said: "Our aim is simple - to change the world."

 

Using the resources of his presidential foundation, Clinton will assist the large cities to create a consortium that will pool the purchasing power of the cities to lower the price of energy-saving products and accelerate the development of new technologies to reduce greenhouse gases.

 

The alliance will also use measurement tools and internet-based communications that will allow cities to establish a baseline on their greenhouse gas emissions and to share information on what works and what does not work with each other.

 

Other cities in the group include Berlin, Beijing, New York, Chicago, Philadelphia and Toronto.

 

They will also stress the use of environmentally-friendly fuels or hybrid technologies for city buses and will look into ways to reduce traffic congestion.