Ice melt, sea level rise and superstorms: Hansen on his magnum opus

Why ice sheets may melt faster than expected, and what that could mean for our near future

In this video Jim Hansen provides a “video abstract” of his latest — and longest — paper, Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2 °C global warming could be dangerous, published this week after a lengthy period in review. He, and his stellar list of co-authors, have also provided an “abbrievated” version of the paper, which I strongly recommend you read.

My abstract is a bit shorter: fresh water from melting ice sheets in Greenland and Antarctica is beginning to change the way that heat moves around in the global ocean, setting up feedbacks that will melt the ice faster. This in turn will lead to much more rapid sea level rise than suggested in the recent IPCC report, and much bigger temperature contrasts between warm and cold oceans in the North Atlantic and around West Antarctica — which will drive the mid-latitude superstorms of the paper’s title.

Not a pretty prospect. And if you think it’s unlikely, consider this. There are already “cold blobs” in the North Atlantic and off West Antarctica, Atlantic storms are becoming much more vigorous , and there are hints of an acceleration in the rate of sea level rise.

Hansen has been right before. I hope, for all our sakes, that this time he’s not.

TDB Today: WACCy weather and a warm year


A classic case of WACCy weather in the northern hemisphere, seen here in a map from the excellent Climate Reanalyzer site, prompts me to discuss the 2013 global temperature numbers, the El Niño-Southern Oscillation, and what sea ice loss is doing to northern hemisphere weather patterns in my post at The Daily Blog this week. We live in interesting times…

Beatin’ the heat: cut carbon or we’re cooked

The area of land affected by extreme heatwaves is expected to double by 2020 and quadruple by 2040, and there’s no way we can stop it happening according to a new paper by Dim Coumou and Alexander Robinson – Historic and future increase in the global land area affected by monthly heat extremes (Environmental Research Letters, open access). However, the researchers find that action to cut emissions can prevent further dramatic increases in heat extremes out to the end of the century.

The paper’s made headlines around the world — see The Guardian, Independent, and Climate Central — most focussing on the inevitability of more, and more intense, heat events in the near future. Dana Nuccitelli at The Guardian provides an excellent discussion of the science behind the new paper so, to avoid reinventing the wheel, I’m going to focus on a fascinating chart from the paper, and then ponder the implications for climate policy.

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Moon-walking with due legal process to a very hot place – Neil Armstrong, coal mining & global warming


On the same day as the death of Neil Armstrong, the first astronaut to step onto the Moon, became public, the NZ High Court moonwalked its way to an off-the-world moment. It decided that greenhouse gas emissions and global warming are off-limits in the planning for an open cast coal mine. That’s as just as ‘out of this world’ as denying that the Moon landings ever happened, argues Simon Johnson.

On Saturday, two bits of news struck home to me very strongly. The first was the death of moon-landing astronaut Neil Armstrong. The second was the High Court decision that open-cast coal mines and global warming are legally and jurisdictionally unrelated in the Resource Management Act.

The moon landing in 1969 I remember very well. As a seven year old, I listened attentively to the ‘one small step’ broadcast. The whole class was silent under the spell of our teacher’s scratchy transistor radio. It’s one of my most strongly held memories of those days. I guess that reflects quite well on that class of seven year olds. They stopped playing bullrush, sniffing with colds, and fighting over lunches to listen attentively to the unfolding of one of humanity’s most historic moments.

While I was still fondly remembering the Moon landing, the next news item struck.

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Uncertainty overdone

Earlier this month James Hansen wrote a trenchant op-ed in the New York Times.  He reiterated the warning that the exploitation of the Canadian tar sands will be game over for the climate, spelt out some of the long-term drought consequences for the US of continued warming and identified notable heat waves of the last decade as most likely due to human-caused climate change. He was clearly anxious to drive home the message that humanity is in serious danger if we carry on exploiting all the fossil fuels we can find. “If it sounds apocalyptic, it is.”

On cue, journalist Andrew Revkin in his Dot Earth blog on the New York Times a few days later reported a meteorologist, Martin Hoerling, who claimed that Hansen had exceeded his brief as a scientist and allowed his policy commitment to overrule scientific caution. Revkin then asked climatologist Kerry Emanuel for his reaction to both Hansen and Hoerling. He received the comment that Emanuel saw overstatements on all sides, and, unsurprisingly, aligned himself with Emanuel.

But there was more to come on Revkin’s blog. A few days later he posted a response to Hoerling by Dan Miller who had assisted Hansen in the preparation of his op-ed. Miller had also been in touch with Emanuel to find out what his concerns were. It turned out they were hardly substantial:

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