‘We must trigger social tipping points’

September 11, 2022 / activist360

The risk of dangerous, cascading tipping points in natural systems escalates above 1.5°C of global warming, states a recent study.

By Yasmin Dahnoun, Ecologist (Creative Commons 4.0).

Multiple climate tipping points could be triggered if global temperature rises beyond 1.5°C above pre-industrial levels, according to a major new analysis published in the journal Science.

Even at current levels of global heating, the world is already at risk of triggering five dangerous climate tipping points, and risks increase with each tenth of a degree of further warming.

An international research team synthesized evidence for tipping points, their temperature thresholds, timescales, and impacts from a comprehensive review of over 200 papers published since 2008 when climate tipping points were first rigorously defined. They have increased the list of potential tipping points from nine to sixteen.

Die-off

The research concludes that we are already in the danger zone for five climate tipping points: melting of the Greenland and West Antarctic ice sheets, widespread abrupt permafrost thaw, the collapse of convection in the Labrador Sea, and massive die-off of tropical coral reefs.

The paper was published ahead of a major conference, Tipping Points: from climate crisis to positive transformation, at the University of Exeter, which will take place next week.

Four of these move from “possible” to “likely” at 1.5°C global warming, with five more becoming possible around this level of heating.

David Armstrong McKay, from Stockholm Resilience Centre, University of Exeter, and the Earth Commission, was the lead author of the report. He said: “We can see signs of destabilization already in parts of the West Antarctic and Greenland ice sheets, in permafrost regions, the Amazon rainforest, and potentially the Atlantic overturning circulation as well.

“The world is already at risk of some tipping points. As global temperatures rise further, more tipping points become possible. The chance of crossing tipping points can be reduced by rapidly cutting greenhouse gas emissions, starting immediately.”

Safe

The Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), stated that risks of triggering climate tipping points become high by around 2°C above preindustrial temperatures and very high by 2.5-4°C.

The new analysis indicates that earth may have already left a “safe” climate state when temperatures exceeded approximately 1°C above preindustrial temperatures.

A conclusion of the research is therefore that even the United Nations’ Paris Agreement goal to avoid dangerous climate change by limiting warming to well below 2°C and preferably 1.5°C is not fully safe.

However, the study provides strong scientific support for the Paris Agreement and associated efforts to limit global warming to 1.5°C, as while some tipping points are possible or likely at this temperature level, the risk escalates beyond this point.

Liveable

To have a 50 percent chance of achieving 1.5°C and thus limiting tipping point risks, global greenhouse gas emissions must be cut by half by 2030, reaching net zero by 2050.

Co-author Johan Rockström, the co-chair of the Earth Commission and director of the Potsdam Institute for Climate Impact Research, said: “The world is heading towards 2-3°C of global warming.

“This sets earth on course to cross multiple dangerous tipping points that will be disastrous for people across the world.

“To maintain liveable conditions on earth, protect people from rising extremes, and enable stable societies, we must do everything possible to prevent crossing tipping points. Every tenth of a degree counts.”

Decarbonising

Tim Lenton, director of the Global Systems Institute at the University of Exeter and a member of the Earth Commission, was a co-author of the report. He said: “Since I first assessed climate tipping points in 2008, the list has grown and our assessment of the risk they pose has increased dramatically.

“Our new work provides compelling evidence that the world must radically accelerate decarbonizing the economy to limit the risk of crossing climate tipping points.

“To achieve that, we now need to trigger positive social tipping points that accelerate the transformation to a clean-energy future.

“We may also have to adapt to cope with climate tipping points that we fail to avoid, and support those who could suffer uninsurable losses and damages.”

Collapse

Scouring paleoclimate data, current observations, and the outputs from climate models, the international team concluded that 16 major biophysical systems involved in regulating the earth’s climate (so-called “tipping elements”) have the potential to cross tipping points where change becomes self-sustaining.

That means even if the temperature stops rising, once the ice sheet, ocean, or rainforest has passed a tipping point it will carry on changing to a new state.

How long the transition takes varies from decades to thousands of years depending on the system.

For example, ecosystems and atmospheric circulation patterns can change quickly, while ice sheet collapse is slower but leads to an unavoidable sea-level rise of several meters.

The researchers categorized the tipping elements into nine systems that affect the entire earth system, such as Antarctica and the Amazon rainforest, and a further seven systems that if tipped would have profound regional consequences.

Interlinked

The latter include the West African monsoon and the death of most coral reefs around the equator.

Several new tipping elements such as Labrador Sea convection and East Antarctic subglacial basins have been added compared to the 2008 assessment, while Arctic summer sea ice and the El Niño Southern Oscillation (ENSO) have been removed for lack of evidence of tipping dynamics.

Co-author Ricarda Winkelmann, a researcher at the Potsdam Institute for Climate Impact Research and a member of the Earth Commission, said: “Importantly, many tipping elements in the earth system are interlinked, making cascading tipping points a serious additional concern.

“In fact, interactions can lower the critical temperature thresholds beyond which individual tipping elements begin destabilizing in the long run.”

‘Unknown territory’: Antarctic glaciers melting at rate unprecedented in 5,500 years: study

June 12, 2022 / activist360

“These currently elevated rates of ice melting may signal that those vital arteries from the heart of the West Antarctic Ice Sheet have been ruptured,” said one researcher. “Is it too late to stop the bleeding?”

By Julia Conley, Common Dreams (CC BY-NC-ND 3.0).

The human-caused climate crisis is pushing crucial glaciers in Antarctica to lose ice at a rate not seen in more than 5,000 years, according to a new study published Thursday.

Researchers at the University of Maine, the British Antarctic Survey, and Imperial College London found that the Pine Island and Thwaites glaciers on the West Antarctic Ice Sheet could cause global sea level rise of up to 3.4 meters, or over 11 feet, in the next several centuries due to their accelerated rate of ice loss.

“That the present-day rate of glacier retreat that has doubled over the past 30 years is, indeed, unprecedented.”

The glaciers—one of which, the Thwaites, has been called the “doomsday glacier” by climate scientists because of its potential to raise sea levels—are positioned in a way that allows increasingly warm ocean water to flow beneath them and erode the ice sheet from the base, causing “runaway ice loss,” the University of Maine team said in a statement.

The researchers examined penguin bones and seashells on ancient Antarctic beaches in order to analyze changes in local sea levels since the mid-Holocene period, 5,500 years ago.

Sea levels were higher and glaciers were smaller during the mid-Holocene, as the climate of the planet was warmer than it is today.

Since then, according to the study published in Nature Geoscience, relative sea levels have fallen steadily and the Thwaites and Pine Island glaciers have stayed relatively stable—until recent decades.

Ice loss was likely accelerated just prior to the mid-Holocene, and since then, the rate of relative decrease in sea levels over the past 5,500 years was almost five times smaller than it is in present day, due to “recent rapid ice mass loss,” according to the scientists.

“That the present-day rate of glacier retreat that has doubled over the past 30 years is, indeed, unprecedented,” wrote Caroline Brogan, a science reporter at Imperial College.

With the Thwaites spanning an area of more than 74,000 square miles and the Pine Island glacier spanning more than 62,600 square miles, the rapid ice loss of the two glaciers could cause major rises in sea levels around the globe.

Dylan Rood of Imperial College’s Department of Earth Science and Engineering, a co-author of the study, likened the two glaciers to arteries that have burst.

“These currently elevated rates of ice melting may signal that those vital arteries from the heart of the West Antarctic Ice Sheet have been ruptured, leading to accelerating flow into the ocean that is potentially disastrous for future global sea level in a warming world,” said Rood. “Is it too late to stop the bleeding?”

The study follows increasingly urgent calls from the Intergovernmental Panel on Climate Change, the International Energy Agency, and climate scientists around the world for an end to fossil fuel extraction, which is needed to achieve net-zero carbon emissions by 2050 and limit the average global temperature from rising more than 1.5°C above preindustrial levels.

Scientists have warned that the accelerated melting of the Thwaites glacier is likely irreversible.

“We’re going into unknown territory,” Scott Braddock, a researcher at University of Maine, told Science News. “We don’t have an analog to compare what’s going on today with what happened in the past.”

The Swiss Alps Are Changing

December 10, 2019 / activist360 / Leave a comment

The Swiss Alps are suffering the effects of climate change. As permafrost zones (rocks and soil that used to be frozen permanently) melt, they have caused massive rock slides.

The famous mountains, The Eiger and Matterhorn, have been hit by rockslides. Villages are also impacted. In 2003, the town of Pontresina built a huge dam to protect itself from mud and rock slides.

Switzerland’s Alpine region is right now in the grip of a climate disaster, as warmer temperatures have seen glaciers shrink by 10 percent in the last five years.