Tag Archives: tipping points

Climate Change & Sustainability

Has the climate tipped?

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‘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.

Continue reading Has the climate tipped? →

Climate Change & Sustainability, Climate Science

Cloud tipping point could yield a cataclysmic 14°C warming

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Clouds could trigger a feedback effect. Stocktrek Images, Inc. / Alamy Stock Photo

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.

Levels of 4°C threaten civilisation as we know it. At 6°C we worry about the survival of the human race. However, at that point Tapio Schneider and his team at the California Institute of Technology, Pasadena, have found that there may be a further tipping point which heats the planet another 8°C to make it 14°C above pre-industrial levels (New Scientist, so probably pay-walled.)

How is this so? Continue reading Cloud tipping point could yield a cataclysmic 14°C warming →

Climate Change & Sustainability

Trouble at the top of the world

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Arctic summer sea ice minimum was the sixth lowest on record. So we can all relax, right?

Wrong.

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 →

Climate Action, Climate Change & Sustainability, Climate Policy & Planning, Climate Science

Science shows the need for urgent climate action

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In August last year in Climate clippings 181 (Item 5) I linked to a report by Climate Analytics examining the impacts on Australia of limiting global temperature rise to 1.5°C and 2°C.

For me the crux of the report is this, from a discussion piece at The Conversation:

    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℃.

If we go to 2℃, we will have a very different climate and there is a good chance we won’t be able to stabilise there. The bad news is that if we just carry on we’ll reach 1.5C by 2024, and 2C by 2036. Continue reading Science shows the need for urgent climate action →

Climate Action, Climate Policy & Planning, Climate Science

Tipping point for climate action?

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Recently the Climate Commission issued a report in its The Critical Decade series on Extreme Weather looking at the issues of

  • Heat
  • Bushfires
  • Rainfall
  • Drought, and
  • 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)

Continue reading Tipping point for climate action? →

Climate Action, Climate Policy & Planning, Climate Science

Climate clippings 39

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Greenland ice

Predicting tipping points

Tim Lenton is now attempting to link the basic theory of climatic “tipping points” with observed early warning signals.

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 →

Climate Science

Climate clippings 15

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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.

Continue reading Climate clippings 15 →