Today’s report on deep decarbonisation delivered to Ban Ki-moon, the UN Secretary-General, offers a new perspective on how countries can avoid dangerous climate change and achieve sustainable development. The report, produced by the Deep Decarbonisation Pathways Project which is overseen by the UN Sustainable Development Network, describes the joint efforts of independent experts from 15 countries to find national pathways to making economies based on low-carbon energy consistent with the 2-degree Celsius limit on global warming agreed to by governments in 2010. Such low-carbon pathways are feasible, but to achieve them will require a high degree of global cooperation and a novel design of the climate deal to be reached at the Cop 21 meeting in Paris in December 2015.

The internationally agreed 2-degree C limit on warming (compared with the pre-industrial temperature) reflects the warnings of the world’s leading climatologists, ecologists, agronomists and economists. The world would breach 2 degrees C at grave peril. The droughts, floods, heat waves and extreme storms that are already disrupting the world would intensify dangerously. Even worse, warming of more than 2 degrees could trigger natural feedbacks (such as carbon and methane release from the melting permafrost) causing runaway climate disruptions that would overwhelm the world’s capacities to adjust.

Despite the 2-degree pledge and growing scientific alarm, the world continues to explore, develop, extract and burn fossil fuels at a rate that is increasing rapidly: enough to raise temperatures not just by 2 degrees, but by 4 degrees C or more by 2100. Economic and political momentum is driving the world to the brink. We have just a few years at most to begin the process of shifting to a low-carbon energy.