The issue focused on the role that the US government may play in shaping the global environment.

"The US is the world's leading polluter, polluter of the planet, with a massive greenhouse gas emissions problem that is threatening its own climate climate change goals. We are the only planet on Earth with a serious climate problem – and we should be paying attention," said the climate scientist.

He said the US was the world's top polluter of the planet, with a massive greenhouse gas emissions problem