Tipping Points

[vox_mundi]

Antarctica's Tipping Points Threaten Global Climate Stability
https://phys.org/news/2024-12-antarctica-threaten-global-climate-stability.html

Antarctica is approaching a series of cascading tipping points that could reshape ecosystems and intensify global climate disruptions, according to a new study by an international team of scientists, including researchers from the University of Tasmania.

The study identifies eight potential tipping points spanning physical, biological, chemical, and governance systems. The research is published in the journal Ambio.

These include collapsing ice sheets, invasive species, ocean acidification, and pressures on the Antarctic Treaty System (ATS), which oversees human activity in the region.

The study warns that these tipping points are interconnected, creating a risk of cascading effects.

Melting ice sheets, for example, not only contribute to sea-level rise but also disrupt ocean circulation, which is crucial for transporting heat, carbon, and nutrients around the globe. Such disruptions threaten marine ecosystems, global fisheries, and food security.

... Biodiversity is another key concern highlighted in the report. Rising temperatures and human activities are enabling invasive species to establish themselves, threatening endemic Antarctic organisms.

At the same time, the Southern Ocean's ability to absorb carbon dioxide—a crucial buffer against global warming—is diminishing.

"The interconnected nature of these systems means small failures can quickly escalate," Professor King said. "Without decisive action, we risk triggering a chain reaction with far-reaching and irreversible consequences."

Ida Kubiszewski et al, Cascading tipping points of Antarctica and the Southern Ocean, Ambio (2024
https://link.springer.com/article/10.1007/s13280-024-02101-9

[etienne]

Don't know if is a tipping point, but here is what Wikipedia says about wildfire in California in the 2024 context.

Northern California typically sees wildfire activity between late spring and early fall, peaking in the summer with hotter and drier conditions. Occasional cold frontal passages can bring wind and lightning. The timing of fire season in Southern California is similar, peaking between late spring and fall. The severity and duration of peak activity in either part of the state is modulated in part by weather events: downslope/offshore wind events can lead to critical fire weather, while onshore flow and Pacific weather systems can bring conditions that hamper wildfire growth.

https://en.m.wikipedia.org/wiki/2024_California_wildfires

For sure it is a worrying evolution.

[vox_mundi]

After Millennia as CO₂ Sink, More Than One-Third of Arctic-Boreal Region Is Now a Source
https://phys.org/news/2025-01-millennia-arctic-boreal-region-source.html



After millennia as a carbon deep-freezer for the planet, regional hotspots and increasingly frequent wildfires in the northern latitudes have nearly canceled out that critical storage capacity in the permafrost region, according to a study published in Nature Climate Change.

An international team led by Woodwell Climate Research Center found that a third (34%) of the Arctic-boreal zone (ABZ)—the treeless tundra, boreal forests, and wetlands that make up Earth's northern latitudes—is now a source of carbon to the atmosphere. That balance sheet is made up of carbon dioxide (CO2) uptake from plant photosynthesis and CO2 released to the atmosphere through microbial and plant respiration.

When emissions from fire were added, the percentage grew to 40%.


"While we found many northern ecosystems are still acting as carbon dioxide sinks, source regions and fires are now canceling out much of that net uptake and reversing long-standing trends."

... For example, the study found that while 49% of the ABZ region experienced "greening"—in which longer growing seasons and more vegetation means that more carbon can be photosynthesized and stored—only 12% of those greening pixels on the map showed an annual increasing net uptake of CO2.

Wildfires offset the increasing but spatially heterogeneous Arctic–boreal CO2 uptake, Nature Climate Change (2025)
https://dx.doi.org/10.1038/s41558-024-02234-5

------------------------------------------------------



------------------------------------------------------

Map Reveals Alaskan 'Hotspots' of Extreme Warming
https://www.woodwellclimate.org/arctic-hotspots-climate-stress-in-northern-alaska-siberia/

http://dx.doi.org/10.1029/2023GL108081

------------------------------------------------------

Meanwhile ...

Trump Leaves Paris Climate Agreement, Doubles Down On Fossil Fuels
https://phys.org/news/2025-01-trump-paris-climate-agreement-fossil.html

President Donald Trump on Monday announced the United States' withdrawal from the Paris climate accord for a second time, a defiant rejection of global efforts to combat planetary warming as catastrophic weather events intensify worldwide.

The Republican leader also declared a "national energy emergency" to expand drilling in the world's top oil and gas producer, said he would scrap vehicle emissions standards that amount to an "electric vehicle mandate," and vowed to halt offshore wind farms, a frequent target of his scorn.

He also signed an order instructing federal agencies to reject international climate finance commitments made under the previous administration, and issued a formal letter to the United Nations notifying it of Washington's intent to leave the agreement.

.... Manish Bapna, president of the Natural Resources Defense Council, pushed back: "There is no energy emergency. There is a climate emergency."

[kiwichick16]

Microbial activity will only increase in cool/ cold regions as the planet continues to heat up

[vox_mundi]

Brazil Saw 79% Jump In Area Burned by Fires In 2024: Monitor
https://phys.org/news/2025-01-brazil-area.html



Wildfires in Brazil last year consumed a total area larger than all of Italy, a monitor reported Wednesday, as the country continues to battle blazes often set by farmers and ranchers illegally expanding their territory.

Some 30.8 million hectares (119,000 square miles) of vegetation were burned in Brazil in 2024, a 79% increase from 2023, monitoring platform MapBiomas reported.

https://brasil.mapbiomas.org/en/

Fires in the Amazon, a crucial carbon sink for the rest of the world as well as a global hotspot of biodiversity, accounted for 58% of the damage.

The 2024 figures represent the largest area burned since 2019.

Some 8.5 million hectares of forest burned in 2024, compared to 2.2 million in 2023, and in the Amazon, fires took out more forest than grassland for the first time, according to the data.

... There were 140,328 fires detected by satellite imaging over the year, according to the National Institute for Space Research (INPE).

That was 42% more than the 98,634 fires recorded in 2023—and the most since 2007, when 186,463 forest fires were seen.

Scientists warn that continued deforestation will put the Amazon on track to reach a tipping point where it will emit more carbon than it absorbs, accelerating climate change.

[kassy]

Death by many cuts. Build a big road and people will go live near that. And then they clear some fields by burning. On the current trajectory it won´t be long before it fails to a sink. It´s also bad for rainfall because trees emit many compounds which act as seeds for rain.