According to a controversial model study published on Thursday, even if humans stop emitting greenhouse gases tomorrow, the earth will warm for centuries and the oceans will rise by one meter.
Norwegian researchers report in the journal Nature that the natural driving forces of global warming-more entrained clouds, melting permafrost and shrinking sea ice-have begun to be driven by carbon pollution. Scientific report.
BI’s Professor Emeritus of Climate Strategy, Jorgen Randers, said: “According to our model, when greenhouse gas reduction is used as a single tool to stop permafrost melting, humanity has gone beyond irreversible “The Norwegian Business School told AFP.
“If we want to stop the melting process, we have to do other things, such as absorbing carbon monoxide2 Take it out of the atmosphere and store it underground, and make the surface of the earth brighter. ”
Randers and his colleague Ulrich Goluke used a simplified climate model to predict 2500 years of change in the following two situations: two situations are the immediate stop of emissions, and the planetary warming gas will gradually decrease to zero by 2100.
In a fictitious world, carbon pollution stopped with the switch. In the next 50 years, the earth warmed to about 2.3 degrees Celsius higher than the pre-industrial level, which is higher than the 2015 Paris Agreement. The target is about 0.5 degrees higher.Then cool down
The surface temperature of the earth today is 1.2 degrees Celsius higher than when it began to rise in the mid-19th century.
But starting in 2150, the model began to gradually warm the planet again. In the following 350 years, the average temperature rose by another layer, and the sea level rose by at least three meters.
In the second case, the earth heats up to a level that can destroy the structure of civilization more quickly, but it will almost reach the same point by 2500.
The core finding of the debate by leading climate scientists is that several thresholds or “critical points” in the Earth’s climate system have been crossed, triggering a self-sustaining warming process, as has happened over the past few million years.
One of these driving factors is the rapid retreat of Arctic sea ice.
Since the end of the 20th century, millions of square kilometers of snow and ice-reflecting about 80% of solar radiation back into space-have been replaced by open oceans in summer, while the latter has absorbed the same percentage.
Another reason is the melting of permafrost, which has twice the carbon content of the atmosphere. The third is to increase the amount of water vapor, which also has a warming effect.
The response of the six leading climate scientists to this study (the author admits to be indicative) has varied widely. Some say the results are worthy of follow-up research, while others oppose it.
Richard Betts, head of climate impact studies at the University of Exeter, said: “The model used here…does not show a credible representation of the real climate system.”
“In fact, it is in direct contradiction to more mature and more extensive climate models.”
Mark Maslin, professor of climate science at University College London, also pointed out the shortcomings of the model, called ESCIMO, and called the study a “thought experiment.”
“This study really attracted people’s attention. It is to reduce global carbon emissions to zero by 2050.” This is a goal advocated by the United Nations and supported by more and more countries. “This is just our response to climate change. Start.”
Even the more complex models used in the forecasts of the United Nations scientific advisory body IPCC indicate that unless a large amount of CO is used, the temperature target of the Paris Climate Convention cannot be reached.2 Remove from the atmosphere.
One way is to plant billions of trees. Experimental technology shows that the absorption of CO2 It can be done mechanically, but so far it has not reached the required scale.
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A model of the Earth system shows that even if anthropogenic greenhouse gas emissions cease in 2020, the self-sustaining permafrost will melt, Scientific report (2020). DOI: 10.1038/s41598-020-75481-z, www.nature.com/articles/s41598-020-75481-z
Citation: Ending greenhouse gas emissions may not stop global warming: Study (November 12, 2020) from https://phys.org/news/2020-11-greenhouse-gas-emissions- on November 12, 2020 global.htmlsearch
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