Earth’s Tipping Points
A tipping point is a critical threshold that when crossed, leads to large and often irreversible changes in the climate system. They lead to long-term consequences which are hard or impossible to reverse. Without immediate and deep emissions reductions across all sectors, limiting global warming to 1.5 °C will be impossible, the Intergovernmental Panel on Climate Change (IPCC) has warned.
Examples of tipping points include the Greenland ice sheet melting (the ice sheet contains enough water to raise global sea levels by over 20 feet and its melting is accelerating), The West Antarctic Ice Sheet (WAIS), Amazon rainforest die off (loss of a major carbon sink), and thawing permafrost which releases methane, a planet warming gas, into the atmosphere.
Read a roundup of the headlines:
“Climate tipping points are conditions beyond which changes in a part of the climate system become self-perpetuating. These changes may lead to abrupt, irreversible, and dangerous impacts with serious implications for humanity. Armstrong McKay et al. present an updated assessment of the most important climate tipping elements and their potential tipping points, including their temperature thresholds, time scales, and impacts. Their analysis indicates that even global warming of 1°C, a threshold that we already have passed, puts us at risk by triggering some tipping points. This finding provides a compelling reason to limit additional warming as much as possible.
Our assessment provides strong scientific evidence for urgent action to mitigate climate change. We show that even the Paris Agreement goal of limiting warming to well below 2°C and preferably 1.5°C is not safe as 1.5°C and above risks crossing multiple tipping points. Crossing these CTPs can generate positive feedbacks that increase the likelihood of crossing other CTPs. Currently the world is heading toward ~2 to 3°C of global warming; at best, if all net-zero pledges and nationally determined contributions are implemented it could reach just below 2°C. This would lower tipping point risks somewhat but would still be dangerous as it could trigger multiple climate tipping points.”
Science, Exceeding 1.5°C global warming could trigger multiple climate tipping points
“In 2019 an international team of scientists published a commentary in the celebrated science journal Nature, sounding the alarm of a planet in crisis — and calling for transformative change.
“We are in a state of planetary emergency,” they wrote, departing from the usual sterility of scientific writing. “The stability and resilience of our planet is in peril.”
Yes, they were writing about climate change, but of a particular kind: climate tipping points, elements of the Earth system in which small changes in global temperature can kick off reinforcing loops that ‘tip’ a system into a profoundly different state, accelerating heat waves, permafrost thaw, and coastal flooding — and, in some cases, fueling more warming.”
Grist, The 7 climate tipping points that could change the world forever
“The climate crisis has driven the world to the brink of multiple “disastrous” tipping points, according to a major study. It shows five dangerous tipping points may already have been passed due to the 1.1C of global heating caused by humanity to date.
These include the collapse of Greenland’s ice cap, eventually producing a huge sea level rise, the collapse of a key current in the north Atlantic, disrupting rain upon which billions of people depend for food, and an abrupt melting of carbon-rich permafrost.
At 1.5C of heating, the minimum rise now expected, four of the five tipping points move from being possible to likely, the analysis said. Also at 1.5C, an additional five tipping points become possible, including changes to vast northern forests and the loss of almost all mountain glaciers.
In total, the researchers found evidence for 16 tipping points, with the final six requiring global heating of at least 2C to be triggered, according to the scientists’ estimations. The tipping points would take effect on timescales varying from a few years to centuries.
“The Earth may have left a ‘safe’ climate state beyond 1C global warming,” the researchers concluded, with the whole of human civilisation having developed in temperatures below this level. Passing one tipping point is often likely to help trigger others, producing cascades. But this is still being studied and was not included, meaning the analysis may present the minimum danger.”
The Guardian, World on brink of five ‘disastrous’ climate tipping points, study finds
“Recent climate projections may be underestimating the pace of global warming in an atmosphere damaged by greenhouse gas emissions, because the interaction of powerful climate feedback loops that can accelerate warming are not well-represented in key climate models, an international team of scientists concluded in a study published today in the journal One Earth. Their findings suggest that efforts to reduce emissions require even more urgency to avoid worst-case climate outcomes, the team reported.
“If amplifying feedbacks are strong enough, the result is likely tragic climate change moving beyond anything humans can control,” said co-author Bill Ripple, an ecologist at Oregon State University, and co-founder of the Alliance of World Scientists…”
Inside Climate News, Scientists Examine Dangerous Global Warming ‘Accelerators’