Climate Change: World on the brink of five tipping points

One of the gravest dangers of human-made climate change, as we are witnessing across the world today, is that of the world passing several ‘tipping points’. What are these? Tipping points are climate thresholds which, when passed, become self-sustaining, even if global action manages to stabilize warming in the long run. As far as the global climate goes, some of the more disastrous tipping points include the collapse of the Greenland ice-sheet (which would dramatically increase the sea level around the world), the melting of Arctic permafrost (which would release even more CO2 and methane into the atmosphere, further adding to the heating), the death of coral reefs (causing massive losses to the global food chain), or the disappearance of all mountain glaciers (leading to an environmental and water crisis).

A new study, published in the journal Science on 9 September, states that we are on the brink of many such tipping points, and that some others may have already been passed. The world has heated up by 1.1 degree Celsius since pre-Industrial times (around 1850), and the average global temperature is within striking distance of reaching the 1.5 degree Celsius threshold, which is considered by the United Nations to be the relatively safe upper limit of warming. In this regard, the global study’s title says it all:  Exceeding 1.5°C Global Warming Could Trigger Multiple Climate Tipping Points. It synthesizes current scientific evidence to analyse 16 global climate tipping points, which would trigger the collapse of polar ice, disruptions in the monsoon, forest and coral reef diebacks.

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The work of 11 climate scientists from around the world, the report states that the lower end of the risk estimate of five tipping points may have already been crossed between 0.8 degree and 1 degree Celsius of global warming. However, once the world reaches aor crosses 1.5 degree Celsius of warming, these tipping points move from being possible to likely. These will trigger the collapse of the Greenland ice sheet, the thawing of permafrost, the collapse of the West Antarctic ice sheet, a weakening of the Atlantic Ocean circulation current and the death of tropical coral reefs. Global warming of beyond 1.5 degree Celsius, especially the crossing of the 2 degree warming threshold, will trigger other collapses, including the loss of mountain glaciers and the dieback of the Amazon rainforest.

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The authors of the report say that this means that it’s more urgent than ever that the world’s governments do all they can to reach the target of limiting warming to 1.5 degree Celsius by 2100, set by the 2015 Paris Agreement. “It’s really worrying. There are grounds for grief, but there are also still grounds for hope. The study really underpins why the Paris agreement goal of 1.5C is so important and must be fought for. We’re not saying that, because we’re probably going to hit some tipping points, everything is lost and it’s game over. Every fraction of a degree that we stop beyond 1.5C reduces the likelihood of hitting more tipping points,” says one of the report’s lead authors, David Armstrong McKay at the University of Exeter. The world is currently on a trajectory to heat up by 2-3 degree Celsius above pre-industrial levels by 2100.

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