Economists insists he is optimistic Copenhagen agreement will be reached, but only if rich countries show greater willingness to support developing world
Study finds renewables could provide 40 per cent of global electricity by 2050
Climate minister says Obama's commitment to environment has raised prospects of global agreement at UN summit in December
Global conference will attempt to shape Copenhagen talks by providing update on latest climate science
UN secretary general warns that China and India must do more to cut emissions, sparking fears of Copenhagen stand-off
Official emissions down 1.5 per cent in 2007 on 2006, but key sectors not included in calculations
Former prime minister argues that setting "interim targets" for 2020 at Copenhagen later this year would show emerging economies the West is serious about cutting emissions
International Energy Agency insists that contrary to recent criticism its calls for increase in renewables capacity are entirely unequivocal
Why 2009 will deliver both tough times and tide-turning optimism for green businesses
But Senator insists US is "back in a position of participation, of respecting views and having real discussions"