Representatives from 40 of the world's largest cities were arriving in New York on Monday for a three-day conference on how best to combat global warming, DPA reported. New York Mayor Michael Bloomberg, who is hosting the event dubbed "Role of large cities in addressing climate change," has argued that urban populations in rich as well as poor nations can play a major role in reducing greenhouse gas emissions blamed for global warming. The three-day summit starting on Tuesday will focus on initiatives that can counteract climate change while benefiting businesses and the local economy. Topics of discussion include energy and water use and the creation of so-called green skylines - the construction of energy efficient buildings in new and existing commercial and residential areas. The conference will also discuss ways to transform waste into energy and using recycling systems to reduce city waste, and how financial markets react to climate change in ways that benefit cities and businesses. Mayors and governors of at least 36 of the 40 cities were expected to attend the conference, which ends Thursday with a dinner to be hosted by former US president Bill Clinton.