The debate on whether the world needs stronger greenhouse gas cuts to keep the planet from warming by 2C should be deferred until next year, according to Brazil's lead negotiator at the upcoming talks in Doha.

Nuclear power will only play a limited role in the world's energy future because of its "absurdly high" cost, Al Gore said on Thursday.

Despite several countries, including the US, UK and China, pushing forward with plans for new nuclear reactors, the former vice-president said the economics of nuclear meant that it was unlikely to play a major role.