Castro lambasts Obama as 'weak' on climate change

"Obama is not ignorant. Like (Al) Gore, he knows the grave danger that threatens everyone, but he vacillates and is weak in the face of a blind and irresponsible oligarchy in that country," Castro wrote in an editorial published on Wednesday.

His comments came as negotiators met in Copenhagen to thrash out a deal to curb carbon emissions and stem global climate change. Castro accused rich countries of heaping climate costs on the poor.

"It is likely that in Copenhagen, the most they can achieve is to buy a little time to reach a deal that will really serve to find solutions," wrote Castro. "If they achieve that, then the summit will represent a modest advance."

The former Cuban president, who still leads the Cuban Communist Party, also criticised Obama for accepting a Nobel Peace Prize. The US president will collect the award in Oslo on Thursday. "Now we have to listen to another theatrical speech in Oslo, a new compendium of phrases that mask the existence of an imperial hyper-power."