‘Tipping point’ is a metaphor, first used by science and the media about climate change from about 2005 as this article explains. The metaphor has become topical now because some of the most senior climate scientists on the planet have used it to warn everyone, just before the nations of the world meet in the Conference of Parties of the UNFCCC meet in the first two weeks of December, as they do every year, this time in Madrid, to plan an international response to what was identified in the Rio Earth Summit as dangerous anthropogenic interference [DAI] with the climate system”.
The article, commentary rather than research – Climate tipping points — too risky to bet against – is freely available at Nature. The authors are Timothy M. Lenton, Johan Rockström, Owen Gaffney, Stefan Rahmstorf, Katherine Richardson, Will Steffen and Hans Joachim Schellnhuber with the message;
The growing threat of abrupt and irreversible climate changes must compel political and economic action on emissions.
Commonly 2°C has been seen as the threshold for dangerous climate change, although last year the IPCC report on 1.5°C revealed that at that lower level we enter a zone where tipping points may take us to 4°C and beyond.
I’ll come back to that. However, Tamino at Open Mind points out that while the Arctic warms three to four times as fast as global warming, the Arctic winters are warming at a much faster rate.
Using the NASA data, which is about mid-range in the major players, Tamino finds that the overall average warming rate since 1985 in the Arctic, at 6.48°C/century is fully 3.4 times as fast as the global rate since 1985 of 1.90°C/century. Continue reading Trouble at the top of the world→
The report predicts that half of the world’s identified tipping points – such as the collapse of polar ice sheets and the drying out of the Amazon rainforest – would be crossed under 2C warming, compared with 20% of them at 1.5℃.
The French company that owns the Hazelwood brown coal generator in Victoria – the dirtiest power station in Australia – has issued a “call to arms against coal.” Continue reading Climate clippings 144→
Recently the Climate Commission issued a report in its The Critical Decade series on Extreme Weather looking at the issues of
Sea level rise.
At Radio National’s The World Today Professor Lesley Hughes, a Macquarie University ecologist, talked to Eleanor Hall.
The report looks at extreme weather experience in recent times, such as that documented in the Commission’s report The Angry Summer, puts it in a broader context using the latest science and then uses that as a window to project into the future. The message is plain. The climate has shifted, expect more and more extreme weather and we need to act now.
we really need to view all these events not in isolation but as part of a trend for the future. We need to prepare for them and we need to do our absolute best to cut greenhouse gases to stabilise the climate to prevent them getting to the point at which we cannot adapt.(Emphasis added)
Problem is, these tipping points may not be sudden and dramatic but involve a steady but inevitable increase. When outbreaks of pine beetles first became obvious perhaps the eventual destruction of Canada’s boreal forests was inevitable. But Lenton is making an argument “from almost a mathematical point of view” that there are general properties of tipping points. Continue reading Climate clippings 39→
These posts include a brief mention of a number of news items relating to climate change. They don’t preclude treating any of these topics at more length in a separate post.
They can also serve as an open thread so that we can keep each other informed on important climate news.
Beware the collapse of the planet’s lungs
Amazon drought is consistent with what scientific models predict for a warmer globe.
Normally, rainforests function like great carbon sinks, absorbing a large proportion of the CO2 that human activity produces. But in 2005, thanks to deforestation, the Amazon became a net emitter of carbon dioxide. In that year, the rainforest is estimated to have emitted some 5 billion tonnes of CO2, almost as much as the entire output of the United States.