Obama's call to arms against 'ecologic disaster'

US President Barack Obama has called for stepped-up global efforts aimed at reaching a climate change agreement amid Washington's persistence in disregarding the previous pacts.

"And all of us agreed that it was imperative for us to redouble our efforts," in the lead-up to the Copenhagen meeting which is to come up with a landmark environmental treaty, the US-based ABC News reported on Tuesday.

The US president said the concerned states had to "assure that we create a framework for progress in dealing with what is a potential ecologic disaster."

Scheduled for December, the Climate Change Conference in Denmark is hoped to ratify a replacement for the Kyoto Protocol, which was set-up to combat global warming.

The United States, which alone has generated about 29 percent of the world's total greenhouse gases since the mid-1800s, has refused to implement the protocol to reduce greenhouse emissions.

The treaty, which expires in three years, has been signed by over 30 industrialized countries who pledged to reduce their emissions during a five-year commitment period.

President of the European Commission José Manuel Barroso, who had joined Obama in a related US-European Union Summit, however, said "President Obama changed the climate on the climate negotiations because with the strong leadership of United States we can indeed make an agreement."