Politicians, economists and some natural scientists tend to assume that the climate tipping points in the Earth system, like the loss of the Amazon rainforest or the West Antarctic ice sheet and many such points, are of low probability and are little understood. However, evidence is mounting that these events could be more likely, have high impacts on the planet’s ecosystem and are interconnected across different biophysical systems, potentially committing long-term irreversible changes worldwide.
The analysis of the tipping points helps to identify that we are in a state of “climate emergency” and further strengthens the chorus of calls for urgent climate action worldwide. The Intergovernmental Panel on Climate Change (IPCC) introduced the idea of tipping points nearly two decades ago. Such ‘large-scale discontinuities’ in the climate system were possible only if global warming exceeded five degrees Celcius above pre-industrial levels.
Furthermore, the information summarized in the recent IPCC Special Reports (published in 2018 and September 2019) suggested that tipping points could be exceeded even when the temperature rise is between 1 and 2 °C of warming.
The term “climate tipping points” has become a core concept of discussions about climate change science and is used as a metaphor for abrupt, irreversible, and dangerous climate change by climate scientists and the news media. The IPCC described the concept as “once a given climate threshold is reached, it can cause life on Earth to face prolonged, irreversible changes“.
A tipping point in the climate system is a critical threshold which, if crossed, results in a major, and often irreversible, change in the states of the system.
The IPCC has identified several tipping points in climate change that are critical thresholds in a system that, if crossed, could result in irreversible consequences. Climate tipping points are critical thresholds that, when crossed, push a natural system into an entirely different state, and result in possibly irreversible, catastrophic consequences — including even greater warming — for Earth.
A tipping point is where the threshold for temperatures is crossed, leading to an irreversible shift in the climate system, even though global warming is ending. Tipping points also require self-reinforcing feedback and result in changes to a climate system that are not irreversible over the human timescale. However, crossing the tipping points risks irreversibly perturbing the natural systems which have kept Earth’s climate relatively stable over thousands of years.
From melting the Greenland Ice Sheet to the Labrador Sea’s convection melt and the Amazon rainforest’s disappearance, climate thresholds throw Earth’s systems into catastrophic tailspins. In climatology: “a tipping point is a point where more minor changes become large enough to produce a larger, critical shift, one that may be sudden, irreversible, and result in cascading effects“.
Scientists explain that such change happens on longer timescales, and the limits of computational power make it impossible to accurately depict every climate system’s tipping points or how they interact. The tipping points were considered probable only when global warming exceeded five degrees Celcius above pre-industrial levels.
Assessments have been done in the past, like those of the UN Intergovernmental Panel on Climate Change; the sixth assessment report was released in three parts in 2021 and 2022, suggested most of the main tipping points would be reached if the planet warmed beyond 3.6 degrees Fahrenheit, giving humanity more time to develop mitigation and adaptation strategies.
Abrupt changes in the tipping points are essential because they could dominate climate change impacts far beyond their effect on the way global warming changes relative to emissions.
Since the impacts are inevitable, we must prioritize and ramp up climate mitigation and adaptation. On the mitigation front, it means working in all, and one can limit global warming and not exceed the 1.5-degree celsius tipping point. The same requires transformative global shifts by the developed countries. On the adaptation front, efforts will mean actively preparing for climate impacts coming down the pike and prioritizing resources for already-vulnerable communities.
Concluding, continued GHG emissions will worsen climate change, and future changes will include a warm and more acidic ocean, a warm atmosphere, sea level rise, and drastic changes in precipitation patterns. The Earth is likely no longer in a safe climate since temperatures exceed the warming limit by approximately one-degree celsius. Therefore, even the UN Paris Agreement’s target of keeping global warming well below two-degree celsius and preferably 1.5 degrees celsius might fall short of mitigating severe climate change.
However, to even have a 50% chance to limit global warming by 1.5 °C and to avoid crossing any climate tipping points, GHG emissions must be cut in half by 2030 and eliminated by 2050.