A draft United Nations report has warned that global warming is on its way to breaking the stricter limit set in the UN-sponsored Paris Agreement in the middle of this century unless governments make unprecedented economic changes starting of fossil fuels.
Reuters Newsagency reports that a draft report to be released in October said governments will also need to start sucking carbon dioxide out of the air to achieve the ambition of limiting temperatures to 1.5 degrees Celsius above pre-industrial times.
"There is a very high risk that global warming will exceed 1.5 ° C above pre-industrial levels," wrote the UN panel of experts, based on the current rate of warming and current national plans to limit their emissions. of greenhouse gases.
There was no historical precedent for the scale of changes required in energy use, to move from fossil fuels to renewable energy, and in reforms ranging from agriculture to industry to stay below the 1.5 ° C limit, said.
The draft, from the Intergovernmental Panel on Climate Change (IPCC) of leading UN scientists and obtained by Reuters, said average surface temperatures are about 1.0 ° C above pre-industrial times and that Average temperatures are on the way to reaching 1.5 ° C in the 2040s.
Reducing warming to 1.5 ° C would help limit extremes of heat, droughts and floods, migration of people and even the risks of conflict compared to higher rates of warming, according to the draft summary for the political leaders.
However, a 1.5 ° C rise might not be enough to protect many coral reefs, which already suffer from higher ocean temperatures, and the ice stored in Greenland and West Antarctica, whose melting is raising sea levels.
At a United Nations summit in Paris in 2015, nearly 200 nations set out to limit the rise in the world's average surface temperatures to "well below" 2.0 ° C above pre-industrial times while pursuing efforts to reach the maximum limit of 1.5 ° C.
They commissioned the IPCC report to map the risks of each target.
Reuters reports that the 1.5 ° C limit is especially favored by developing nations most at risk of disruptions to food and water supplies.
The current draft was sent for comments from governments and other experts this week.
Jonathan Lynn, a spokesman for the IPCC, said the text was a work in progress not intended for publication.
"The text can change substantially," he said.
Rather, the draft said that renewables such as solar and wind would have to become the dominant form of primary energy by 2050 to reach the 1.5 ° C target.
"Carbon should be removed quickly in most options down to 1.5 ° C," he said.
At the same time, limiting global warming to 1.5 ° C by 2100 "would imply the removal of carbon dioxide from the atmosphere," he said.
That could mean planting vast forests, which absorb carbon dioxide as they grow, or building power plants that burn wood or other plant matter, and then capture and bury the carbon dioxide they release.
However, that might not be feasible because forests could divert land from food crops.
The draft estimates that humanity could emit just 580 billion tons of greenhouse gases to have a better than 50 percent chance of limiting warming to 1.5 ° C, roughly 12-16 years at current emission rates.
The amounts could be higher if governments allowed temperatures to exceed 1.5 ° C and found a way to reject the global thermostat later in the century.
Original article (in English)