The outcomes of COP29 in Baku inundated us with estimates of how much climate finance is needed for less developed countries to tackle the climate crisis. From the $1.3 trillion per year estimated by the UN—of which the portion for adaptation alone ranges from $215 to $387 billion—to the staggering $7.4 trillion proposed by the Climate Policy Initiative. If these figures seem high, a recent study by the DOE/Pacific Northwest National Laboratory warns that they could become significantly heavier. Once tipping points, or climate points of no return, are crossed, the costs of reversing the effects of climate change can become up to four times higher than those of preventive measures.
Navigating the Uncertainty of Climate Tipping Points
This work ventures into territory where certainties are scarce. Climate science remains quite divided on how likely it is to trigger tipping points and where exactly the point of no return lies.
The latest report from the IPCC, the UN Intergovernmental Panel on Climate Change, has begun to focus much more on such events than in the past. It defines them as “a critical threshold beyond which a system reorganizes, often abruptly and/or irreversibly” and attributes the highest probability to tipping points such as permafrost thawing, the slowdown of the Atlantic Ocean circulation, and the melting of the Greenland ice sheet.
Even more complex is predicting with sufficient accuracy the behavior of a complex system—the Earth’s climate—and its repercussions on other equally complex systems, such as those characterizing the biosphere.
Climate Spending 4 Times Higher If Tipping Points Are Crossed
Researchers at the DOE used simplified mathematical models to describe the fundamental behaviors of tipping points, providing insights that could guide future intervention plans. To identify imminent climate tipping points—a challenging task—the authors rely on the assessment of “observable precursors,” factors that can serve as early warning signals.
The study’s main finding is straightforward: there is a clear and significant asymmetry between damage and restoration. Reversing climate change requires much greater effort than causing it. For example, the study suggests that if global warming leads to the complete melting of sea ice by 2100, simply bringing emissions back to 2024 levels might not be enough to restore it.
The researchers also identify a so-called “overshoot window.” This is a buffer period during which climate intervention costs rise linearly rather than exponentially after a tipping point is crossed. This interval is influenced by factors such as the slow warming of ocean waters. However, once this window closes, climate costs increase dramatically, highlighting the urgency of early action.