Natalie Bennett, leader of the Greens, believes the report further illustrates the importance of industrial countries including Britain, United States and China cutting greenhouse gas emissions.
She said: "George Osborne, if his views hold sway, would hold significant responsibility for the mass human tragedy that would follow.
"He is also missing huge opportunities, both economic opportunities for Britain and opportunities to provide effective global leadership.
"Support for renewables - particularly offshore wind and tidal power, for which Britain has rich resources and existing skills from the North Sea oil and gas industry - could develop our already successful and growing green industries.
Ms Bennett also spoke out on Ed Miliband's pledge that Labour would freeze energy bills if it won the next election.
She said: "A serious programme of government funded insulation for our leaky, hard to heat homes would create more jobs, cut carbon emissions and slash fuel poverty.
"Unfortunately, by contrast, Ed Miliband's proposal would provide only a short-term measure on fuel poverty.
"As the CBI points out, almost one million people are already employed in 'green' jobs, and Britain has a £5bn trade surplus in green jobs and services."
Customer support service by UserEcho