Just as a line of tumbling dominoes initiates a chain reaction, breaching a climate tipping point can trigger a cascade of environmental consequences such as accelerated global warming, rising sea levels, and intensifying weather extremes. But there’s more at stake than just environmental catastrophe. A new study reveals that the cost of reversing the damage soars almost four times once a tipping point has been crossed.

Published today in the journal npj Climate and Atmospheric Science, the study is the first to quantify the financial implications of controlling climate tipping points before and after they occur. It uncovers the astronomical cost required to reverse the effects of climate change, such as restoring melted polar sea ice.

Climate tipping points, such as melting ice sheets and dwindling tropical coral reefs, have drastic environmental repercussions. When these thresholds are breached, we see effects like flooded coastal cities and lost biodiversity. Despite understanding the serious consequences, we know little about the financial burden of managing these tipping points.

The study’s lead author, mathematician Parvathi Kooloth, reveals that the effort and cost required to reverse the effects and reinstate the climate system to its pre-tipping point state are nearly fourfold if we wait until after the tipping point has been crossed. This applies to all tipping points, whether it’s restoring tropical coral reefs or regrowing sea ice.

Kooloth explains, “If you wait until after the threshold is crossed, the degree of intervention needed to restore the climate system escalates rapidly. Our work confirms that it’s much more expensive and invasive to fix problems after they’ve occurred than to prevent them.”

Each tipping point is unique, influenced by variables such as cloud cover or heat transport in nearby ocean waters. These factors shape how the climate system changes post-tipping point and determine the specifics of any intervention strategy.

Despite these differences, all tipping points share a core equation that describes their fundamental nature. This commonality enables researchers to study the shared behavior of tipping points using simplified mathematical models, gaining insights that could guide future intervention strategies and potentially highlight early warning signals.

Kooloth’s team also discovered that some tipping points have an “overshoot window”. During this period immediately after a tipping point is crossed, the cost of intervention doesn’t spike immediately but instead increases linearly with time. This happens when, for instance, nearby ocean waters take longer to heat up, delaying rapid changes.

This delay offers a small window of extra time before severe changes escalate. However, this grace period comes at a high price. Once the overshoot window is crossed, intervention costs rise dramatically. The larger the overshoot window, the higher the cost.

Not all effects of climate change can be reversed, such as the loss of flora and fauna due to rapid and prolonged environmental changes. Moreover, some effects could require even more effort to reverse than it took to push the climate system past a tipping point.

Kooloth emphasizes that the process of causing and reversing climate change is asymmetrical. We might quickly cross a tipping point, but the journey back to a stable climate system could be significantly longer.

“The path forward and the path backward are often not the same,” Kooloth explains. “We may need to reduce emissions much further than current levels to restore the ice, once all our sea ice has melted. This asymmetry is crucial to consider as we decide on our future direction.”