"We're nearly halfway through the 2020s, dubbed the most decisive decade for action on climate change. Where exactly do things stand? Climate impact scholar Johan Rockström offers the most up-to-date scientific assessment of the state of the planet and explains what must be done to preserve Earth's resilience to human pressure."
This 20 minute video really is worth watching to inform you to step up climate action.
Johan Rockström is a co-developer of the planetary boundaries framework, Johan Rockström works to understand Earth’s resilience to human pressure. From his TED biography:
Before focusing on the planetary scale, Rockström's research focused on water resources and building resilience in water-scarce regions. After completing a PhD at Stockholm University's Systems Ecology Department in 1997, he spent over a decade working on applied water research in tropical regions.
Rockström cofounded the Stockholm Resilience Centre and is currently director of the Potsdam Institute for Climate Impact Research in Germany. He co-chaired the EAT-Lancet Commission on healthy diets from sustainable food systems, published in 2019 and he is co-chair of Future Earth and the Earth Commission. In May 2024 he was awarded with the 2024 Tyler Prize for Environmental Achievement for his pioneering work on the Planetary Boundaries framework.
From Nature (April 2020) Climate tipping points — too risky to bet against. Timothy M. Lenton, Johan Rockström, Owen Gaffney, Stefan Rahmstorf, Katherine Richardson, Will Steffen & Hans Joachim Schellnhuber, https://www.sprep.org/attachments/VirLib/Regional/climate-tipping-points.pdf
The evolution of Planetary Boundaries:
The evolution of the planetary boundaries framework. Licenced under CC BY-NC-ND 3.0 (Credit: Azote for Stockholm Resilience Centre, Stockholm University. Based on Richardson et al. 2023, Steffen et al. 2015, and Rockström et al. 2009)
You can read a full synopsis of the talk at Counterpunch, August 23, 2024, Tipping Points – Where Things Stand https://www.counterpunch.org/2024/08/23/tipping-points-where-things-stand/
Climate Tipping Point Implications for Australia
Australian scientists assessed the regional impact of tipping points in 2023 and released a new report in February 2024. The ARC Centre for Climate Extremes issued this summary: Dangerous climate tipping points will affect Australia. The risks are real and cannot be ignored
In 2023, we saw a raft of news stories about climate tipping points, including the accelerating loss of Greenland and Antarctic ice sheets, the potential dieback of the Amazon rainforest and the likely weakening of the Atlantic Meridional Ocean Circulation.
The ice sheets, Amazon rainforest and the Atlantic ocean circulation are among nine recognised global climate tipping elements. Once a tipping point is crossed, changes are often irreversible for a very long time. In many cases, additional greenhouse gases will be released into the atmosphere, further warming our planet.
New scientific research and reviews suggest at least one of Earth’s “tipping points” could be closer than we hoped. A milestone review of global tipping points was launched at last year’s COP28.
What will these tipping points mean for Australia? We don’t yet have a good enough understanding to fully answer this question.
Our report, released overnight, includes conclusions in three categories: we need to do more research; tipping points must be part of climate projections, hazard and impact analyses; and adaptation plans must take the potential impacts into account.
Under Biosphere and carbon cycle tipping points, the workshop identified the already parlous state of eco-system change in Australia:
Ecosystem collapse is happening across Australia, and 19 ecosystems from the Antarctic to the tropics have been identified with a clear collapse profile (Bergstrom et al. 2021). The most significant ecosystems at risk of collapse in Australia are alpine ecosystems, coastal ecosystems, and temperate forests. Coral reef die-off, including of the Great Barrier Reef, is considered a climate tipping point, and has implications for Australian regional climate as well as for ecosystems, industry and our society. Other ecosystem collapses are not considered climate tipping points but have important implications for Australia. For example, temperate forests observed a massive fire regime change, with fire return intervals becoming shorter in recent decades. Local and regional ecosystem collapses are a massive issue, and worthy of attention beyond what we cover here.
Main conclusions of this Australian workshop:
The consequences of passing a tipping point may be realised within decades (e.g., Amazon dieback, coral reef die-off). The consequences of passing other tipping points may be partially realised within decades (with notable societal consequences) but continue unfolding over 100s to even 1000s of years (e.g., loss of mass from Greenland and Antarctic ice sheets).
- The effects of tipping points on the global climate are generally not currently accounted for in projections based on climate models. This means that effects of tipping points are also not included in national climate projections and impact assessments for Australia and may represent significant risks on top of the changes that are generally included. Larger and more rapid warming and sea-level rise are the main possible consequences, but other effects may include abrupt changes to the El Niño Southern Oscillation, rainfall patterns, and rainfall variability that are not represented in climate model projections.
- The effect of some remote tipping points in Australia are likely small over any time scale (e.g., permafrost thaw, Amazon die-back), while others (e.g., sea-level rise resulting from rapid ice-sheet retreat) would have a measurable and material effect in Australia this century.
- Some changes from triggering tipping points set up a ‘tug of war’ with other influences, for example a ’collapse’ of the Atlantic Meridional Overturning Circulation (AMOC) may result in substantial regional changes countering the general effect of climate warming (including regions of notable cooling in the northern hemisphere).
o Mitigation: limiting further global warming limits the chances of triggering tipping points. Playing our role in the global effort to reduce emissions to net zero is required to minimise the chances of triggering tipping points.
o Adaptation: we can consider where, when and how we may take prudent action to reduce the potential impacts of passing tipping points.
We cannot be precise about the impacts of these tipping points on Australia, but we know passing tipping points would have considerable direct and indirect impacts.
Although we have an incomplete understanding of the impacts of global tipping points on Australia, we need to consider the possible outcomes, because the impacts are so potentially great. This requires a risk management framework with an appropriate view of different types of uncertainty, likelihood and consequence, as well as an adequate view of complex, interconnected systems. Such a framework could use techniques such as the ‘storylines’ approach. Current planning projects could start to account for the ‘low likelihood high impact’ storylines that include climate tipping points.
For example, construction plans for new critical infrastructure with a long lifetime and low tolerance for failure (e.g., nuclear waste storage and hospitals), could incorporate ‘worst case’ sea-level allowances that assume high-end Greenland and Antarctic ice-sheet contributions, of around ~2 m by 2100 into building specifications. - To increase our understanding of tipping points, and how they may affect Australia and our region, we need increased attention and research. This includes paleoclimate records, theory and process understanding (including a hierarchy of models) and observations needed to scan for early warning signs. Australia’s climate model, the Australian Community Climate and Earth System Simulator (ACCESS) is the only Earth System Model built in our hemisphere. It is essential and can be a useful tool in climate tipping points research of relevance to Australia, and related topics such as local ecosystem collapses.
Discussing Overshoot and tipping Point risks
A recent study published 1 August 2024 models the risks of passing tipping points with overshooting the 1.5C- 2C Paris temperature target.
After 1.5C risks e4scalate for us with tipping risk increasing with every 0.1 °C of overshoot peak temperature.
Above that, there is a non-linear acceleration in tipping risk for peak overshoot temperatures above 2.0 °C resulting in more than 3% tipping risk increase per additional 0.1 °C peak temperature for overshoot temperatures exceeding 2.5 °C peak warming.
If all the promises of the UN Climate conferences are fulfilled, we are currently heading for at least 2.7C of warming by 2100.
Our study reveals that following current climate policies until 2100 may lead to high tipping risks even if long-term temperatures return to 1.5 °C by 2300. Under such an emission pathway, we report a tipping probability of 45% (median estimate, 10–90% range: 23–71%) until 2300 and of 76% (median estimate, 10–90% range: 39–98%) in the long term. Scenarios following pledged NDCs under the UNFCCC in 2020 until 2100 fail to adhere to the Paris Agreement LTTG, and even when subsequently designed such that temperatures return to 1.5 °C (median) after overshoot, we find that they are insufficient to avoid tipping risks (median estimate: 30%, 10–90% range: 10–56% until 2300). We find that tipping risk increases with every 0.1 °C of overshoot peak temperature. Further, we find a non-linear acceleration in tipping risk for peak overshoot temperatures above 2.0 °C resulting in more than 3% tipping risk increase per additional 0.1 °C peak temperature for overshoot temperatures exceeding 2.5 °C peak warming. This underscores the importance of the Paris Agreement climate objective24 to hold warming to ‘well below 2 °C’ even in case of a temporary overshoot above 1.5 °C.Our results show that only achieving and maintaining net zero greenhouse gas emissions, associated with a long-term decline in global temperatures, effectively limits tipping risks over the coming centuries and beyond in line with earlier studies. Our findings imply that stabilisation of global temperatures at or around 1.5 °C is insufficient to limit tipping risk in the long term. In order to effectively minimise this risk, our study suggests that temperature needs to return to below 1 °C above pre-industrial level.
References:
CSIRO Workshop Report. (2024) Understanding the risks to Australia from global climate tipping points. CSIRO, Australia. https://www.csiro.au/-/media/Environment/CSIRO_Tipping-Points-Report.pdf
Möller, T., Högner, A.E., Schleussner, CF. et al. Achieving net zero greenhouse gas emissions critical to limit climate tipping risks. Nat Commun 15, 6192 (2024). https://doi.org/10.1038/s41467-024-49863-0
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