The risk of climate tipping points is upon us

• weka
• 4 years ago
• Categories: climate change, science
• Tags: climate tipping points

TL;DR

• the IPCC was for many years too conservative in its predictions and position around tipping points.
• current science is suggesting a likelihood of reaching catastrophic tipping points much sooner than expected
• if we keep doing what we are doing, we can expect tipping points to be reached and climate catastrophe
• some economists are still operating on the old IPCC assumptions and think there is a cost/benefit to be had around climate action because there is little risk
• current nation state pledges will give us 3C warming
• to avoid tipping points and catastrophe “warming must be limited to 1.5 °C. This requires an emergency response”

The longer version from the Nature commentary piece,

Politicians, economists and even some natural scientists have tended to assume that tipping points¹ in the Earth system — such as the loss of the Amazon rainforest or the West Antarctic ice sheet — are of low probability and little understood. Yet evidence is mounting that these events could be more likely than was thought, have high impacts and are interconnected across different biophysical systems, potentially committing the world to long-term irreversible changes.

Here we summarize evidence on the threat of exceeding tipping points, identify knowledge gaps and suggest how these should be plugged. We explore the effects of such large-scale changes, how quickly they might unfold and whether we still have any control over them.

In our view, the consideration of tipping points helps to define that we are in a climate emergency and strengthens this year’s chorus of calls for urgent climate action — from schoolchildren to scientists, cities and countries.

…

Some scientists counter that the possibility of global tipping remains highly speculative. It is our position that, given its huge impact and irreversible nature, any serious risk assessment must consider the evidence, however limited our understanding might still be. To err on the side of danger is not a responsible option.

If damaging tipping cascades can occur and a global tipping point cannot be ruled out, then this is an existential threat to civilization. No amount of economic cost–benefit analysis is going to help us. We need to change our approach to the climate problem.

Full article with the science is here.