South American monsoon heading towards ‘tipping point’ likely to cause Amazon dieback

By The Guardian - Jonathan Watts@jonathanwatts -  4 Oct 2023

‘Shocking’ study finds Amazon rainforest will be unable to sustain itself and transport moisture once ‘regime shift’ occurs.

The South American monsoon, which determines the climate of much of the continent, is being pushed towards a “critical destabilization point”, according to a study that links regional rainfall to Amazon deforestation and global heating.

The authors of the report said they found their results “shocking” and urged policymakers to act with urgency to forestall a tipping point, which could result in up to 30% less rainfall, a dieback of the forest, and a dire impact on food production.

The study, published on Wednesday in Science Advances, examines how forest degradation and monsoon circulation are interlinked.

Using past observations and computer modeling, it finds that the Amazon and the South American monsoon are “one coupled system”, in which the evapotranspiration by the tropical rainforest recycles moisture from the Atlantic Ocean so that it can move south across the continent.

Human degradation of the Amazon – by land clearance, fire, logging, and mining – is pushing that system towards a tipping point, after which drier conditions would be expected to cause an abrupt “regime shift” in the rainforest, which would be unable to sustain itself and transport moisture.

Other biomes in the region would also be affected, along with swathes of agricultural land because the monsoon stretches thousands of miles south from the Amazon to the River Plate (Rio de la Plata) basin. There would also be a climate impact because the Amazon – which would be worst affected – has historically served as an important carbon sink, though another study this week suggests it is now so degraded that it is at best carbon neutral. A dieback of the forest would release enormous amounts of carbon.

The researchers on the Amazon-monsoon paper saw several precursors of the tipping point, including falling rainfall in many areas, the steady lengthening of the Amazon dry season, reduced soil moisture and the increasing frequency and intensity of droughts. There have been three statistically one-in-100-year droughts in the space of a single decade.

“It is shocking to see these signs of destabilization,” said the lead author, Nils Bochow, of the University of Tromsø and the Potsdam Institute of Climate Impact Research. “But we shouldn’t lose hope. We can still act. We need stricter rules regarding the rainforest.”

Global heating is adding to the pressure on the forest. Not included in their paper because it is too recent is this year’s fierce dry season, during which many Amazon rivers have fallen far below their average for this time of year, leading to navigation problems, water shortages, and mass mortalities of dolphins and fish.

Previous studies have suggested a tipping point could be reached when 20% to 30% of the Amazon is cleared, though there is considerable uncertainty about exactly where the point might be. Currently, between 17% and 26% of the rainforest has been destroyed, and at least that has been degraded.

The paper does not give a prediction of when the tipping point might take place, though its authors say their findings confirm the risks and the likelihood that such a tipping point is much closer than other possible climate tipping points, such as the collapse of the Greenland ice sheet.

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Although deforestation in the Brazilian Amazon has halved since Brazil’s center-left president, Luiz Inácio Lula da Silva, came to power at the start of the year, the forest continues to shrink. In Bolivia, the loss is accelerating.

Niklas Boers, a professor of Earth system modeling at the Technical University of Munich and the Potsdam Institute, compared the Amazon-coupled monsoon system to a chair that is tilting further and further back to a point where even a breath of wind could knock it over.

“My emotional response“My emotional response“My emotional response is anger,” Boers said. “With every square kilometer of deforestation, every fraction of the degree of global warming, we are raising the risk of a tipping point. Yet, it is incredibly simple to just stop deforestation. It is an absolutely unique ecosystem that we really can’t afford to lose.”

Commenting on theCommenting on theCommenting on the paper, Dominick Spracklen, an Amazon expert and professor of environmental science at the University of Leeds, said the study was worrying. “This rapid switch to a dry climate would have catastrophic implications for people living in Amazonia,” he wrote. “The study highlights the urgent need for people across Amazonia to work together to find ways to reduce deforestation, prevent further loss of forest, and start to restore areas that have been lost in recent years.”

By VG.NO - WILD ELGAAEN - 05 October, 2023

Temperature pants in September: have never seen anything like this

September was almost one degree warmer than the average, and half a degree warmer than the previous record from 2020. The fierce elevations are surprising.

The short version

• Earth has experienced its warmest September on record, according to the EU's climate monitoring service.
• The average temperature ended at 16.38 degrees, which is 0.93 degrees above the average for the months of September between 1991 and 2020.
• Research leader Gunnar Myhre at CICERO believes that the explanation lies in global warming and a reduction in cooling particles in the atmosphere.
• 2023 is set to be the warmest year on record. Several countries in Europe have had heat records in September.

- Researchers are having a bit of trouble explaining the tremendous increase that is now being seen.

Research leader Gunnar CICERO - The Center for Climate Research is a Norwegian institute for interdisciplinary climate research.to VG.

- There have been suggestions as to what caused the temperature jump in September among scientists, but there is no good explanation other than that we are seeing the effect of global warming and a reduction in cooling particles in the atmosphere.

Earth has experienced the warmest September ever recorded and close to one degree above average, according to the EU's climate monitoring service.

The Earth's average temperature ended at 16.38 degrees, which is 0.93 degrees above the average for the months of September between 1991 and 2020.

This year, this number ended up 0.5 degrees above the previous heat record for September 2020.

- It's a jump you haven't had before. There has previously been a steady rise in temperature, but these trousers are new, says Myhre.

- I have never seen anything like this in my 30 years in this profession, he adds.

The hottest September ever by an extraordinary marginEarth has experienced the warmest September on record and close to one degree above average, according to the EU's…

El Nino

2023 has already set a record for the highest recorded temperatures in history.

In July, heat record after heat record was set in Canada and the USA with temperatures close to 50 degrees  - a heat that has already claimed several lives.

Temperatures in the North Atlantic this summer broke all previous records, and ice levels in Antarctica seem to be getting worse every day.

Photo: JENNIFER GAUTHIER / Reuters / NTB

Read more: Extreme heat, crazy fires, and floods are ravaging the world this summer: Nothing will be the same as before

Myhre in CICERO points out that the world is heading into the El Niño weather phenomenon.

El Niño is a condition of unusually high surface temperatures in the central and eastern Pacific near the equator. An El Niño episode affects the weather over much of the Earth and affects the global average temperature.

The heat records are piling up: - WorryingTØYEN (VG) Four heat records in a row and the hottest June ever. Researchers are concerned, but at Klimahuset in Oslo, the focus is…

Myhre says that it is what causes the biggest year-to-year variations in global temperature, but that the warming from it usually only comes later in autumn and winter.

- The summer temperature shows less year-to-year variation as a result of El Niño.

Photo: GUILLAUME SOUVANT / AFP / NTB

Expect fluctuations

Several countries in Europe have had heat records in September and a warm start to October. Globally, 2023 is now set to be the warmest year ever recorded

In Spain, the month of October has started with new heat records.

- We can expect more of these heat records, more frequent extreme rainfall, and more forest fires. We don't know when it will happen, next year it may have turned the other way, but we know that these episodes of extreme rainfall will come, says Myhre.

Flere counties in Several municipalities in Norway were hit hard when the extreme weather "Hans" hit this summer. More weather like this, there will be.

- Although– Selv om- Even if there will be years with little of it, that does not negate the fact that we are in a trend with more of it. There are fluctuations, he explains.