The world can, by acting urgently, curb carbon emissions enough to avert worst-case scenarios for climate change, UN experts said as they met in Berlin to weigh options for action.
"The literature here shows that deep cuts in greenhouse gas emissions ... remain possible," said Ottmar Edenhofer, who helped oversee the latest volume in a report by the UN's Intergovernmental Panel on Climate Change.
Achieving this goal, Edenhofer warned, would require a break from today's relentlessly upward trend in emissions. It would entail "challenging technological, economic, institutional and behaviour change", he said.
The United Nations announced that global investments in renewable energy slumped 14 per cent last year, with China pouring more money into the sector than Europe for the first time on record.
Investments in renewables apart from hydroelectricity dipped to US$214.4 billion last year, down US$35.1 billion from the previous year and 23 per cent below the record set in 2011, according to a report from the UN Environment Programme.
Envoys and scientists from the climate change panel's 195 member countries are meeting after the panel issued its starkest ever warning about the perils of a ravaged climate system for future generations. The risk of conflict, hunger, floods and mass displacement increase with every upward creep of the mercury, the IPCC said.
"The impacts of climate change will leave no part of the world untouched and unaffected," IPCC chairman Rajendra Pachauri said.
The upcoming volume is the last major piece of the Fifth Assessment Report - the first overview by the Nobel-winning climate panel since 2007.
A draft summary of the report says there is a 15-year window for affordable action to safely reach the UN's target of limiting warming to two degrees Celsius over pre-industrial times. The goal remains attainable if "all countries" act quickly to ease carbon emissions, it says. "Delaying mitigation through 2030 will increase the challenges."