Comments 1 to 8:

1. nigelj at 07:48 AM on 16 June, 2018

   Other research: Antarctic ice is melting three times as fast as a decade ago.  This is obviously very concerning. What are implications for sea level rise by 2100? Has anyone calculated this? 

   I find the list of research above very comprehensive, but in a confusing order. Wouldn't it make more sense to order it science first, then human impacts, then mitigation?

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2. Riduna at 11:48 AM on 16 June, 2018

   In their Paper, Hansen et al 2016 note that . . . . ‘sea level reached +6.9 m in the Eemian, a time that we have concluded was probably no more than a few tenths of a degree warmer than to-day’. Mean global temperature is predicted to be well in excess of the Eemian by 2100.

   While the Paper does specify the magnitude of sea level rise likely by 2100, it can be argued that, given that CO2/CH4 concentrations in the atmosphere already exceed by 40%/267% the levels present during the Eemian thermal meximum, sea level rise in excess of the level then reached is at least possible by 2100.

   You may also be interested in this video in which Dr Hansen discusses the work embodied in Hansen et al 2016. Based on decadal doubling of ice mass loss during the 21st century, I estimate SLR by 2100 would exceed 6 metres. This view seems to be supported by recent research undertaken by the IMBIE Team and published on 12 June 18 in Nature.

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3. Riduna at 11:52 AM on 16 June, 2018

   Correction:  The 2nd para should begin by saying 'While the Paper does not specify the magnitude ...

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4. Ari Jokimäki at 15:10 PM on 16 June, 2018

   Nigelj, I change the order of the papers weekly so that each subsection gets the "headline section" once in three weeks.

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5. william5331 at 06:10 AM on 17 June, 2018

   I wonder if that is indeed true - that the poorest will suffer the most.  Yes, the poor in the slums and favelas of the world will likely be in dire straights but the bigger they are the harder they fall.  If sea level rise overcomes the cities of the world that have been placed where rivers meet the sea, the economic strain on these countries will be extreem.  We have seen how poorly even a very rich country like the USA coped with Katrina.  Multiply that an order of magnitude or two and the highly over-extended economies of such countries may well collapse.

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6. william5331 at 06:16 AM on 17 June, 2018

   1 Nigel

   Depends if this is part of an exponential curve or just a blip in a linear curve.  (can we call a linear graph a curve.  Probably).  A few more years should clarify this.  If each decade we tripple the melting then we raise 1.03 to the eighth power to get the melting by the end of the century and integrate under the curve to see how much total water has entered the oceans.  Not a pretty picture.

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7. william5331 at 10:13 AM on 17 June, 2018

   Apologies.  I must have been having a mathematical melt down.  The story is more like this.  If we are indeed trebbling the melt rate every decade and if this is truly an exponential curve then it means that the melt rate is increasing by about 11.6% each year (1.116 raised to the tenth power equals 2.997).  You then have to raise 1.116 to the eighty second power (number of years remaining in the century)  to see what the melt rate will be at the end of this century.  Clearly a ridiculous answer (I hope).  I think we will find that after a couple of more decades, we won't see a trippling each decade from the previous decade.  It does suggest, though, that we are in for far more than 3.5mm per year for the rest of the century.

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8. nigelj at 13:12 PM on 17 June, 2018

   It's hard for me to see exponential rise in melting of the antarctic, like a doubling or tripling per decade, given most climate trends are following more of a quadratic trend. But I agree its going to be far more than 3.5mm per year, and I think multi metre sea level rise by 2100 is a real possibility.

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