Further warming will lead to more catastrophic consequences such as severe fire fires
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Even with moderate emissions of greenhouse gases, a scenario is currently expecting to warm the planet by approx. 3 ° C, there is 1-in-10 chance of reaching 7 ° C heating in about 200 years. It is, according to a climate model that has investigated what could happen in the next thousand years.
“Three degrees are alredy very bad, of race,” says Andrey Ganopolski at the Potsdam Institute for Climate Impact Research in Germany. “Seven is not twice as bad as 3 or even three times as bad. It’s probably 10 times worse because many things are nonlinear.”
The model also shows that even if the emissions stopped tomorrow, there is about a 1-in-10 luck that the planet could still heat with more than 3 ° C.
How much warmer the planet gets depends partly on how much CO2 and other greenhouse gases we pump into the atmosphere and partly on how sensitive the climate is to increase greenhouse gases.
The amount of heating that would occur in the long run after a doubling of CO2 levels in the atmosphere is called the equilibrium climate. It depends on various quick feedback effects that occur when temperatures rise, such as Increse in water vapor in the atmosphere and changes in cloud behavior. Studies suggest that the equilibrium cluster could be anywhere from 2 ° C to 5 ° C, but for models that run beyond 2100, it is assumed to be 3 ° C.
Ganopolski and his team Instateead finely tuned their model to investigate what the effect would be if the equilibrium cluster is different from this expectation.
Their model also includes further and prolonged carbon feedback effects such as the release of CO2 and methane from permafrost and wetlands. Previous models that look beyond 2100 have not included both CO2 and Methane Feedbacks, says Ganopolski.
Inclusion of both can have a great influence, he says, because higher CO2 leads to more methane being released and vice versa.
For an assumed equilibrium sensitivity of 3 ° C, the team’s results are similar to them in other studies, leading to the heating of wood 3 ° C just after 2200 for a moderate indication. For higher asomed sensitivity, the model projects heating up to 7 ° C.
While the 23rd century may seem far away, it is not so far away with regard to human generations, Ganopolski says. “I have grandchildren who will be lovely in the next century.”
The reason why there is so much uncertainty about the equilibrium cluster is because aerosol emissions have received the heating effect of greenhouse gases, says Ganopolski. A reduction in shipping emissions is believed to have contributed to the recent rapid heating, for example.
The effects of aerosols are extremely complex, making it difficult to quantify their cooling effect. “At the moment we cannot rule out high climate sensitivity,” he says.
“An emission path that we think will come to, for example, 2 ° C in 2100 could be much higher or much lower depending on Thisse Fundaiments,” says Andy Wiltshire at Met Office, the UK’s National Weather Service.
This was already well known, Wiltshire says, but is usually expressed in terms of the percentage likelihood of meeting a specific goal. This paper shows it in a different way. “What I like about the paper is the way the information is presented,” he says.
If equilibrium cluster is on the low side and future emissions are limited, heating of 3 ° C can still be avoided, Ganopolski says – but he thinks it is already too late to limit the heating to below 2 ° C.
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