A recent study published in Science Advances shows that predicting when critical climate tipping points will happen is much harder than scientists previously thought.
These tipping points, such as the collapse of the Atlantic Meridional Overturning Circulation (AMOC), melting polar ice sheets, or changes in tropical rainforests, could cause rapid and irreversible climate changes with severe consequences.
Researchers from the Technical University of Munich (TUM) and the Potsdam Institute for Climate Impact Research (PIK) have identified three main reasons why predicting these events is so challenging.
Three major sources of uncertainty
First, predictions depend on assumptions about the physical mechanisms behind climate changes and future human actions. These assumptions are often too simplistic, leading to significant errors.
Second, there is a lack of long-term, direct observations of the climate system. The available data might not accurately represent the Earth system components, like the AMOC, that are crucial for these predictions.
Third, historical climate data is incomplete. There are large data gaps, especially from the distant past, and the methods used to fill these gaps can introduce errors. This makes it difficult to use historical data to predict future tipping points accurately.
The case of the AMOC
To illustrate their findings, the researchers examined the AMOC, a vital ocean current system. Previous predictions based on historical data suggested that the AMOC could collapse between 2025 and 2095.
However, the new study found that the uncertainties are so large that these predictions are not reliable.
Using different data sets and assumptions, predicted tipping times for the AMOC ranged from 2050 to 8065. This wide range shows just how complex and uncertain these predictions are. Knowing that the AMOC might tip sometime within a 6,000-year window is not practically useful.
The need for better data and understanding
The researchers conclude that while predicting climate tipping points is appealing, current methods and data are not reliable enough.
“Our research is both a wake-up call and a cautionary tale,” says lead author Maya Ben-Yami. “There are things we still can’t predict, and we need to invest in better data and a more in-depth understanding of the systems in question. The stakes are too high to rely on shaky predictions.”
While this study shows that we cannot reliably predict tipping events, it does not mean such events won’t happen.
The possibility of tipping points remains, and statistical methods can still identify which parts of the climate system are becoming more unstable. This includes the AMOC, the Amazon rainforest, and ice sheets.
Moving forward with caution
Co-author Niklas Boers emphasizes the importance of caution. “The large uncertainties imply that we need to be even more cautious than if we were able to precisely estimate a tipping time.
We still need to do everything we can to reduce our impact on the climate, first and foremost by cutting greenhouse gas emissions. Even if we can’t predict tipping times, the probability for key Earth system components to tip still increases with every tenth of a degree of warming.”
In summary, while predicting the exact timing of climate tipping points is currently beyond our reach, reducing greenhouse gas emissions and understanding our climate better are crucial steps in mitigating potential risks.
