Polar Ice Loss Quickens

[Greedave]

Hi to anyone who is reading. I am new to this forum and I saw this story on the BBC News website about the acceleration in ice loss in Antarctica and Greenland and thought it would be of interest.

http://www.bbc.co.uk/news/science-environment-12687272

I really wish people would start climate change much more seriously (I know I am preaching to the converted on here).

[clv101]

Welcome Greedave. Indeed the ice-sheet response to climate forcing is a fascinating and critical area. It's quite likely that Greenland has already past a 'tipping point', the question is whether it loses most of its mass in hundreds or thousands of years.

It is worth noting though, that even if the acceleration rates continue (22 Gt/yr Greenland and 14.5 Gt/yr Antarctica), which few think is realistic, today's loss of 475 Gt/yr only reaches 3760 Gt/yr by 2100 and represents a total of 53cm of sea level rise.

Those folk talking of more than 1 meter by 2100 have a hard time justifying it!

[Greedave]

Thanks for the reply. You make a very valid point about people trying to justify a rise of 1m by 2100. I believe that we shouldn't exaggerate the facts when trying to raise awareness of this issue as it discredits the cause, which is exactly what we don’t want. If it’s 53cm then it’s 53cm, just because it’s smaller number doesn’t mean we shouldn’t do something about it. Anyway I will stop ranting now before I really go off on one!

[kenneal - lagger]

This is a good source of Ice data straight from the horse's mouth, David - http://nsidc.org/ - with weekly updates here - http://nsidc.org/arcticseaicenews/.

A linear rate of loss may only give 560 sea level rise but so many of the changes we are seeing are changing at an exponential rate that I don't see the ice melt not following this trend. Expect the best rate but plan for the worst would be my maxim.

I wouldn't buy anywhere within 10m of sea level. If word gets out that sea levels are rising faster than at first thought, you could end up with a house that you couldn't sell. That goes for proximity to an eroding coastline. I'd give that about 10 miles, just in case.

Rising sea levels will float ice off the bedrock much sooner which will allow it to be attacked by warm sea water from underneath as well as warm air above. The water attack will cause more melting than the air attack as the water has a much greater specific heat, i.e. it can carry much more heat than air. The thinning of the ice from top as well as bottom will, in turn, cause more uplift at an ever increasing rate.

[biffvernon]

Speaking as somebody who now lives below sea level (at high tide) I think that's unnecessarily alarmist. Our house survived the 1953 breaches of the flood defences and it would do the same again. It's not so much about sea level rise as about continued investment in sea defences. There will come a point when further spending becomes uneconomic but we are at least a century away from that.

[caspian]

Those folk talking of more than 1 meter by 2100 have a hard time justifying it!

I think those predictions are based on the assumption of some sort of discontinuity event, such as a large-scale loss of ice from the WAIS. Given the precarious nature of some of the ice shelves and the acceleration of glaciers such as the Pine Island Glacier, there is arguably a potential for sea levels to rise dramatically in a very short space of time. The loss of the WAIS would be a truly apocalyptic event.

[Greedave]

Speaking as somebody who now lives below sea level (at high tide) I think that's unnecessarily alarmist. Our house survived the 1953 breaches of the flood defences and it would do the same again. It's not so much about sea level rise as about continued investment in sea defences. There will come a point when further spending becomes uneconomic but we are at least a century away from that.

Spending money on sea defences doesn't tackle the root cause of the problem, all it does is delay the consequences for our descendants in say 100 years time. I fully respect the fact that you want your home defended but as sea levels rise the potential for flooding also increases and the spend required to mitigate the effects rises exponentially as well.

[Blue Peter]

Those folk talking of more than 1 meter by 2100 have a hard time justifying it!

Stuart has a relevant post, though he's edited it to say that there's a mistake.

Still, things don't stop at 2100, and the trend doesn't look good,


Peter.