‘Scientists might want to write in capital letters, ‘ACT NOW IDIOTS’, but they need to say that with facts and numbers,’ said Kaisa Kosonen, from Greenpeace, who observed the negotiations. ‘And they have.’
The Intergovernmental Panel on Climate Change (IPCC) report shows unprecedented changes were needed across society to limit global warming to 1.5C above pre-industrial levels.
The review of thousands of scientific papers sets out the impacts of temperature rises of 1.5C compared to 2C, and what is needed to curb temperatures at that level.
Impacts ranging from increased droughts and water scarcity to extreme weather, spread of diseases such as malaria, economic damage, and harm to yields of maize, rice and wheat will be less severe at 1.5C than 2C.
Sea level rises would be 10cm lower with a 1.5C temperature rise compared to 2C by 2100, while there would be worse impacts on coral reefs and the Arctic at higher temperatures.
Matthew Spencer, Oxfam’s director of campaigns and policy said: ‘Climate change has set our planet on fire, millions of people are already feeling the impacts, and the IPCC is clear that things could get much worse without immediate action.
‘The faster governments phase out coal, embrace the renewable energy revolution and move to protect communities at risk, the more lives and livelihoods will be spared.’
He warned the world was already seeing the beginning of ‘massive displacement and a shocking rise in hunger’ – and unless temperatures stayed below 1.5C, island nations would disappear beneath rising seas.
Rachel Kennerley, climate campaigner for Friends of the Earth, said: ‘Just like ignoring credit card statements so that repayments only become sharper and steeper, this report shows that weak responses will make it harder in the long-run.
‘Right now it’s difficult, but not impossible, to contain climate chaos, but the window of opportunity will close for good the longer we delay.’
She warned the predicted loss of all coral reefs if governments could not contain warming would mean a massive loss of fish that people rely on for food and costing lives and livelihoods.
She said: ‘That is the kind of reality we must face if governments don’t take notice of this report.’
Dr Stephen Cornelius, chief adviser on climate change at WWF, said the world was already seeing the loss of natural habitats and species, shrinking ice caps and rising sea levels.
He said: ‘We know what is needed to limit global warming to 1.50C and we can do it relying mostly on proven technologies such as decisively scaling up renewable energy and halting deforestation.
‘We have the targets, we have the solutions and the difference between impossible and possible is political leadership. WWF calls on leaders to accelerate climate action immediately.’
Stephanie Pfeifer, chief executive of the Institutional Investors Group on Climate Change (IIGCC) which represents investors with trillions of pounds of assets under management, said the report showed limiting global warming to 1.5C is what was needed.
‘We also know that bold action to address climate change offers 26 trillion US dollars [£20 trillion] in economic benefit across the global economy through to 2030.
Why do we need to limit global warming to 1.5C?
While warming of 2C above pre-industrial levels has widely been thought of as the threshold beyond which dangerous climate change will occur, vulnerable countries such as low-lying island states warn rises above 1.5C will threaten their survival.
Their concerns meant a pledge to pursue efforts to limit temperature rises to 1.5C was included – after tough negotiations – alongside the commitment to keep them “well below” 2C in the global Paris climate agreement in 2015.
When the target was put into the Paris Agreement, relatively little was known about the climate risks that would be avoided in a 1.5C warmer world compared with a 2C warmer world, or about the action needed to limit temperature rises to that level.
So the UN’s Intergovernmental Panel on Climate Change (IPCC) was tasked with providing the answers.
It warns the world is well off track to keep to the 1.5C limit.
Even with the promises countries have made as part of the Paris Agreement to cut the greenhouse gas emissions that cause global warming, the world is set to breach the 1.5C threshold by around 2040.
Based on those promises, we are heading for 3C by 2100 and even warmer after that.
As more greenhouse gases lead to more warming, stabilising the planet’s temperature at any level will require emissions to fall to zero overall.