Arctic sea ice melting faster than expected

[bascule]

http://scienceblogs.com/islandofdoubt/2007/05/be_afraid_be_very_very_afraid_1.php?utm_source=mostemailed&utm_medium=link

 

New estimates show that arctic ice may almost completely melted by 2020

[Icemelt]

Posted by: Doug Alder | May 1, 2007 06:17 PM

"My overriding concern is with the thermohaline pump because if the polar ice cap is melting at a much faster rate then it stands to reason that so are Greenland's glaciers and that means a much greater influx of fresh water into the northern Atlantic, reducing salinity and halting or at least severely slowing down the great Atlantic "conveyor belt". The result of that will not be pretty - that will be "interesting times" a la the old Chinese curse indeed"

 

I seem to recall, a while ago a large frozen lake in Canada melted, discharging a massive amount of fresh water into the North Atlantic and stopping / slowing the conveyor belt / pump. I believe the result was a fairly rapid entry into a glacial period.

 

Surely the global warming enthusiasts should therefore view the possible "halting or at least severely slowing down the great Atlantic "conveyor belt" resulting in a reversal of the current trend as our salvation, although the effects in Northern Europe could I suspect be disastrous.

 

So are we back to worrying about a rapid descent into next glacial period ? Whilst this is what many have been suggesting for some time, it would seem that this might happen rather sooner than expected if these calculations are correct and the thermohaline pump stops.

[jackson33]

there are many sources, indicating ice melting is very slow in the north and non-existent in the south.

 

as for salinity and fresh water introducing to the oceans, man has blocked run off water from the continents at ever increasing rates. the US alone has done so to a said 65% or so efficiency. that a mighty big chuck of water.

 

i would concede rain water into the oceans from storms could make a difference. there also seems to be no natural response in nature or that it could not react to lack of salt, opposed to reactions to heat.

[Icemelt]

130,000 years ago, when global temperatures were almost 4°C higher than at present, most if not all of the Northern hemisphere ice melted. However by 25,000 YBP global temperatures had plummeted to 9°C less than today, and the refreezing of the Arctic Ocean was well under way. Temperatures remained at 8°C to 9°C below current levels until about 12,000 YBP when there was a very rapid rise. During only 250 years temperatures had risen by 6°C (0.024°C pa) to just 2°C below current levels, and by 10,000 YBP they were only half a degree below today’s temperature.

 

Greenland temperatures rose even more dramatically during this period, dwarfing any increases we currently experience, as can be seen in the chart below.

 

 

Now the CO2 level during the Arctic refreezing years varied between 230ppm to 185ppm, as compared to the current ~380ppm today. Whilst the volume of water produce from Arctic ice is small in comparison to all the oceans, might it be reasonable to suggest that, if all the Arctic ice should melt, this should provide an additional sink into which a significant proportion of CO2 might dissolve without increasing the current CO2 concentration in the oceans and closing the gap to saturation. Let’s not forget that really cold water loves to gobble up CO2 really quickly.

 

Taking this one stage further, if the atmospheric CO2 concentration should begin to decrease under these circumstances, and as a result temperatures begin to fall, perhaps the combination of this and other factors, such as the interruption of the ocean pumps, might indeed reverse the current trend and herald our entry into the next glacial period.

 

As can be seen in the chart above, the falls in temperature have historically been almost as sudden as the increases.

[1veedo]

there are many sources, indicating ice melting is very slow in the north and non-existent in the south.

Really? Like can you give an example?

 

PS: This means I want a reference.

[bascule]

I seem to recall, a while ago a large frozen lake in Canada melted, discharging a massive amount of fresh water into the North Atlantic and stopping / slowing the conveyor belt / pump. I believe the result was a fairly rapid entry into a glacial period.[/color]

 

Source?

 

Surely the global warming enthusiasts should therefore view the possible "halting or at least severely slowing down the great Atlantic "conveyor belt" resulting in a reversal of the current trend as our salvation, although the effects in Northern Europe could I suspect be disastrous.

 

Reversal of the current trend? Source?

 

So are we back to worrying about a rapid descent into next glacial period ?

 

Are we? Source?

 

Whilst this is what many have been suggesting for some time, it would seem that this might happen rather sooner than expected if these calculations are correct and the thermohaline pump stops.

 

Source?

 

I'm sorry, I'm just not one for prolonged anecdotes...

 

Do you have a peer reviewed scientific paper arguing each of these specific claims? Or are you perhaps drawing facts from one paper then using them to come to your own conclusions?

[Icemelt]

So here we have it - temperatures are rising faster than ever

 

Er - well maybe not in Greenland then

 

But then who cares what happens to the temperature in Greenland

 

[iNow]

New estimates show that arctic ice may almost completely melted by 2020

 

 

http://dsc.discovery.com/news/2007/10/08/walrus_pla_zoom0.html?category=animals&guid=20071008104500

 

Scientists and conservationists are expressing alarm at the appearance of thousands of walrus on Alaska's northwest coast, a dramatic demonstration of the effects of diminished Arctic sea ice brought on by global warming....

 

 

 

http://www.youtube.com/watch?v=5B0JT6Qbp-E