Latest science on sea level rise

Last Tuesday I attended the Inaugural Lecture by Professor Tim Naish – Understanding Ice Sheets and Sea-levels

Project Rameka Trustee Simon Johnson suggested I put some lecture notes on this blog as Dr Nick Smith is currently travelling around the country consulting with the public on emissions targest for 2020. He will be in Nelson on Friday the 17th July. Paul Kennett has put further details on

Professor Naish gave a fascinating lecture to a packed house. Here is a summary of the notes:

Background: In 2001 IPCC said the max expected sea level rise this century would be 0.88m. Then in 2007 IPCC decided to remove all scientific uncertainties and said it would be 0.18 min to max 0.59m (the range is because there are a range of emissions scenarios – note that earlier this year IPCC said global emissions were higher than their highest scenario had projected). This has resulted in a lot of scientific work to remove the uncertainties.

Prof Naish has specialised in sea level rise, and recently managed the Andril Program in Antarctica where four nations collaborated to get the best icecore samples ever (98% readable), and deeper than ever (1000m). The results correlated surprisingly well with scientific work done in other parts of the world.

In summary, 1.0 m sea level rise this century is now the mainstream expectation in the scientific community.
2m by 2100 is possible if there is ‘Runaway Retreat” (ie, the West Antarctic Ice Sheet erodes rapidly) and some scientists believe that we are seeing the start of this now.

This rise will not be globally uniform.

If, as some expect, runaway retreat happens then parts of the northern hemisphere (ie Canada and the USA) will have 4m sea level rise by 2200.

He finished by saying that Copenhagen negotiations later this year were critical to determine future pathways. The last time we had 350-400 mil ppm co2 in the atmosphere the world was +3-4 degrees warmer (in 1900 we had 280-290 co2 ppm).

He pointed out that 60 million people now live within 1 m of sea level, and that that will grow to 130 million people this century.

In a nutshell, he didn’t want to be scare mongering, but the less that is done, the faster and more severe will be the climate change.

Unfortunately, judging from Dr Nick Smith’s address, our government will be using 2007 science at Copenhagen. This underestimates the impacts of climate change.

Professor Naish’s final slide was of his two small children.

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