Glasgow, Scotland – One phrase, really just one number, dominates climate talks in Glasgow, Scotland: the magic and the elusive 1.5.
This is in line with the international goal of limiting future warming to 1.5 °C (2.7 °F) from pre-industrial times. This is in some ways a somewhat confusing number that just wasn’t a major part of talks seven years ago and was a political suggestion that later proved incredibly important scientifically.
Scientists have found in several reports that stopping warming to temperatures of 1.5 or more could prevent or reduce some of the most devastating future climate change, and for some people it is a matter of life or death.
The 1.5 figure is now the “wider objective” of the Glasgow climate talks, called COP26, said conference chairman Alok Sharma on the first day of the conference. Then on Saturday he said the conference, which takes a break on Sunday, was still “trying to keep 1.5 alive.”
For protesters and activists, the phrase is “1.5 to survive”.
And 1.5 is closer than it seems. That’s because it may seem like 1.5 degrees from now, but because it’s from pre-industrial times, it’s actually only 0.4 degrees (0.7 degrees Fahrenheit) from now. The world has warmed by 1.1 degrees (2 degrees Fahrenheit) since pre-industrial times.
This is not the year when the world average was 1.5 above pre-industrial times for the first time. Scientists usually mean a multi-year average of more than 1.5 because the temperature – while rising over a long period like an escalator – has small teeth at the top and bottom of the long-term trend, such as a step up or down on an escalator. Down .
But it is coming fast.
Scientists calculate the carbon pollution that can be produced by the burning of fossil fuels before it is baked 1.5 degrees. A report from the Global Carbon Project a few days ago found that 420 billion tons of carbon dioxide were left in that budget and humanity emitted 36.4 billion tons this year. The report found that there are about 11 years left at current levels – which are not falling but rising.
To get there, scientists and the United Nations say the world needs to cut its current emissions by about half by 2030. It is one of three goals that the United Nations has set for success in Glasgow.
“It’s physically possible (limiting the heat to 1.5 degrees), but I think it’s politically impossible in the real world, except by miracles,” said Columbia University climate scientist Adam Sobel. “Of course we shouldn’t stop advocating for it.”
A dozen other climate scientists told The Associated Press essentially the same thing – that the world could stay within 1.5 degrees if dramatic emissions reductions begin immediately. But they don’t see any signs of that happening.
That 1.5 figure may be a big number now but that’s not how it started.
At the insistence of small island nations who said it was a matter of survival, 1.5 was placed near the end of negotiations in the historic 2015 Paris climate agreement. It is mentioned only once in the text of the deal. And that part lists the primary goal of pursuing efforts to limit warming to “2 °C above pre-industrial levels” and to limit temperature rise to 1.5 °C above pre-industrial levels.
The 2-degree target was the current target from the failed 2009 Copenhagen conference. The target was initially interpreted as 2 degrees or, if possible, significantly lower.
But in a way both “1.5 and 2 degree C thresholds are somewhat arbitrary,” Stanford University climate scientist Rob Jackson said in an email. “Every tenth of a degree counts!”
2 degrees was chosen because it is “the warmest temperature you can estimate the planet has ever seen in the last million years,” said University of East Anglia climate scientist Corinne Lequere, who helped write the carbon budget study, said Glasgow climate talks
When the Paris Agreement threw in the figure of 1.5, the United Nations tasked its Nobel Prize-winning group of scientists – the Intergovernmental Panel on Climate Change, or IPCC – to study what would happen between 1.5 degrees of warming and 2% of Earth’s warming. What will be the difference in degree of warming.
The 2018 IPCC report found that stopping warming at 1.5 degrees, compared to 2 degrees, would mean:
– Reduction in deaths and diseases due to heat, haze and infectious diseases.
More than half of the people will face water scarcity.
– Few coral reefs can survive.
Summers without sea ice in the Arctic are less likely.
– The West Antarctic Ice Sheet may not kick into irreversible melting.
– Seas will rise about 4 inches (0.1 m) low.
– More than half of animals with back bones and plants will lose most of their habitat.
– There will be much less heat waves, rain and drought.
“For some people it’s without a doubt a life-or-death situation,” said Cornell University climate scientist Natalie Mahowald, the report’s lead author at the time.
Johan Rockström, director of the Potsdam Institute for Climate Impact Research, said in an interview at the Glasgow conference that the finding that there is a huge difference on Earth with very little damage at 1.5 is the biggest climate science has seen in the past six years.
“It gets worse and worse when you get over 1.5,” Rockstrom said. “We have more scientific evidence than ever before that we really have to aim for landing at 1.5, which is the safe climate planet limit.”
“Once we cross 1.5 we enter a scientific danger zone in terms of increased risk,” Rockstrom said.
In a new IPCC report in August, the world hit 1.5 in each of the four main carbon emissions scenarios in the 2030s.
Even when scientists and politicians talk about 1.5, they are usually talking about an “overshoot”, in which a decade or so of temperatures hits or passes 1.5, but then usually Back down with some kind of technology that sucks carbon out of the air, Stanford’s Jackson and others said.
As hard as it is, negotiators can’t give up on 1.5, said Canadian Parliamentarian Elizabeth May at her 16th climate talks.
“If we don’t hang on to 1.5 when it’s technically feasible, we’re almost criminal,” May said.
