There is no question that Peter Wadhams was seriously alarmed by the speed of ice loss in 2012. As this chart shows, if the trend over the previous decade up to 2010 had continued, all the September sea ice would have been gone by 2016. It was entirely proper to issue this warning in view of the evidence, as shown in the chart above. There would still have been big chunks of ice in the sea but not enough to prevent a ship from going anywhere in the Arctic Ocean. However, as the chart shows, the ice volume rebounded dramatically by 3000 km3 in 2013-14. It has since kept falling, apart from small increases in 2017 and 2018. 2019 was again close to the 2012 record minimum. If we now continue the trend since 2014, which equals the longer trend since 1992, the zero date will be in the 2030s.

This observation raises important problems in statistical interpretation. The underlying drivers of warming are the rising levels of CO2 and methane, which are generally accepted in climate science to cause acceleration in warming feedbacks. That means the default prediction would be that the rate of Arctic sea ice melt should accelerate, as was seen in the first decade of this millennium. Scientists who study such alarming data have a duty to bring it to public attention.

It may be that the big increase in 2014 was akin to a “dead cat bounce”, that the sudden collapse of sea ice to below 20% of its long term level since 1979 brought unknown factors into play sustaining a residual amount of ice.

We can imagine three scenarios, an accelerated collapse to an ice free Arctic this decade, a continuation of the current trend to zero ice by the 2030s, or some miraculous reversal of the trend so ice hangs around for several more decades, as believed by the IPCC.

A good article was published today at http://www.realclimate.org/index.php/ar ... se-debate/ It explains how climate scientists deal with deniers on the one hand and with alarmists on the other. It is clear to me that Professor Wadhams should not be grouped with the crazy alarmists of Extinction Rebellion who are discussed in this article, as his projections were entirely justified based on observed physical trends. Despite this, of course the loopy deniers have tarred him with the alarmist brush, because as the article explains, deniers always prioritise politics over evidence.

https://www.theguardian.com/commentisfr ... ce-penguin

It's your regular Arctic death-spiral update with Brenda the Civil Disobedience Penguin
First Dog on the Moon

What solution is Brenda offering, I wonder? When we hear, "There is still time," always it's still about cutting our emissions.

DWill wrote:What solution is Brenda offering, I wonder? When we hear, "There is still time," always it's still about cutting our emissions.

Cutting emissions is like turning down the tap in a bath that has the plug in, but not turning the tap off. Eventually the bath will overflow. Pulling the plug means removing existing carbon from the air. 'There is still time' makes no sense without a paradigm shift in climate policy to support geoengineering.

Latest on the Arctic is that the winter ice freeze is just not happening. This year is by far the worst ever as the chart below from this excellent article https://phys.org/news/2020-10-sea-ice-a ... -late.html shows

I agree your analogy is valid, but was wondering to which solution Brenda might be referring with her "not too late" caution.

And although I've come around to thinking that carbon drawdown is a necessity, I also think it wise to remember that the benefits of any proposed methods are still speculative. That means that letting up on the pressure to decarbonize, ostensibly to lessen economic pain, is risky. The 'green economy' is still the way to go, and it isn't as hard as it may sound to pursue it and also begin seriously testing ways to draw down carbon.