If nations do everything they can to fight climate change, the world can still meet one of two internationally agreed goals to limit global warming. But the planet is blowing past the second threshold, which scientists say will protect Earth more, a new study shows.
The world is potentially on track to keep global warming on or a shadow below 2 degrees Celsius (3.6 degrees Fahrenheit) warmer than pre-industrial times, a goal that once seemed out of reach, according to a study published Wednesday in the journal Nature.
This will only happen if countries not only meet their specific promised national targets for limiting CO2 emissions by 2030, but also get through on more distant promises to reach net zero-carbon emissions by the middle of the century, the study says.
This 2 degree warmer world still represents what scientists characterize as a deeply disturbed climate with tougher storms, higher seas, extinction of animals and plants, disappearing corals, melting ice and more people dying of heat, smog and infectious diseases. That’s not the goal world leaders say they really want: 1.5 degrees Celsius (2.7 degrees Fahrenheit) since pre-industrial times. The world will blow past this more prominent and alien target unless dramatic new emission reductions are promised and achieved in this decade and probably within the next three years, study authors said.
Both targets of 1.5 degrees and 2 degrees are part of the Paris Climate Pact from 2015 and the Glasgow follow-up in 2021 appointment. The 2-degree goal goes back years earlier.
“For the first time, we may be able to keep warm under the symbolic 2-degree mark with the promises on the table. Of course, this presupposes that the countries follow the promises, “said study author Malte Meinshausen, climate researcher at the University of Melbourne.
It’s a great if outside climate scientists and authors, say. This means that political leaders are actually doing what they promise
The study “only examines this optimistic scenario. It does not check whether governments are making efforts to implement their long-term goals and whether they are credible,” said Niklas Hohne from Germany, a scientist from the New Climate Institute who analyzes climate action promises. Tracker and was not part of this study. “We know governments are far from implementing their long-term goals.”
Hohne’s team and others who follow promises have similarly found that it is still possible to limit the warm-up to 2 degrees that Meinshausen’s team has. The difference is that Meinshausen’s study is the first to have been peer-reviewed and published in a scientific journal.
Of course, the 2-degree world requires countries to do what they promise. But cheaper wind and solar energy have shown that cuts in carbon emissions can come faster than expected, and some countries will exceed their promised cuts, Meinshausen said. He also said that the way climate action works starts with promises and then policies, so it is not unreasonable to take countries at their word.
For the most part, he said, limiting heating to 2 degrees is still a big improvement compared to just five or ten years ago, where ‘everyone laughed like’ ha, we’ll never see goals on the table that bring us closer to 2 degrees’, “said Meinshausen. “Goals and implemented policies can actually turn the needle towards future temperatures. I think optimism is important for countries to see. Yes, there is hope.”
About 20% to 30% of that hope is due to the Paris climate deal, but the rest is due to previous investments from countries that have made green energy technologies cheaper than dirty fossil fuels such as coal, oil and natural gas, Meinshausen said.
But even though it’s good news, it’s not all good, he said.
“We also do not have a margin of error (by barely limiting to 2 degrees), nor do the promises put us on a path close to 1.5 degrees,” Meinshausen said.
In 2018, UN scientific expert teams examined the differences between the 1.5- and 2-degree boundaries and found significantly worse and more extensive damage to Earth by 2-degree warming. So the world has recently been trying to reach the goal of 1.5 degrees possible.
The Earth has already warmed at least 1.1 degrees Celsius (2 degrees Fahrenheit) since pre-industrial times, often considered the end of the 19th century, so 2 degrees warming really means another 0.9 degrees Celsius (1.6 degrees Fahrenheit) warmer than now.
Meinshausen’s analysis “looks good and solid, but there are always assumptions that can be important,” said Glen Peters, a climate scientist who tracks emissions with the Global Carbon Project.
The biggest assumption is that nations will somehow reach promised net zero carbon emissions, most of them by 2050, but a decade or two later for China and India, said Peters, research director for the Cicero Center for International Climate Research in Oslo, Norway.
“Giving promises for 2050 is cheap, backing them up with necessary short-term actions is difficult,” he said, noting that for most countries there will be five or six elections between now and 2050.
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