Tell-tale signs of tipping

Early warning systems of approaching climate tipping points are possible in principle and could considerably reduce risks to society, reports a review published online in this week in Nature Climate Change.

A tipping point occurs when a relatively small external change forces an apparently disproportionate response in a system, shifting it from one stable state to another. In society such change can be marked by civil unrest; in climate systems it is marked by physical impacts, such as dieback of the Amazon rainforest or melting of the Greenland ice sheet. Predicting tipping points, such that early warning becomes feasible, has proved elusive.

Tim Lenton considers recent scientific progress on the early warning of climate tipping points, focusing on statistical techniques for detecting the change in a system, such as a sluggish response to disturbance or increased variance, as well as the research needed to develop early warning systems.

In a related feature article, Mason Inman looks at the progress that scientists are making in detecting abrupt change in ecological systems. Small-scale changes, such as the point at which a lake becomes unproductive, could be easier to prevent, and new studies — drawing on both computer models and field data — offer encouraging signs that detecting changes at this level is possible and may scale-up to other systems. If so, then scientists will be one step closer to identifying vulnerable systems and stopping regime shifts before they happen.

doi: 10.1038/nclimate1143

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