(Part of the How to Talk to a Global Warming Skeptic guide)
Objection: Sure, sea ice is shrinking in the Arctic, but it is growing in the Antarctic. Sounds like natural fluctuations that balance out in the end.
Answer: Overall, it is true that sea ice in the Antarctic is increasing.
Around the peninsula, where there is a lot of warming [PDF], the ice is retreating. This is the area of the recent and dramatic Larsen B and Ross ice shelf breakups.
But the rest of the continent has not shown any clear warming or cooling and sea ice has increased over the last decade or so.
This is not actually a big surprise.
In fact, it is completely in line with model expectations that CO2-dominated forcing will have a disproportionately large effect in the north. The reasons lie in the much larger amount of land in the northern hemisphere and the fact that the ocean's thermal inertia and ability to mix delay any temperature signal from the ongoing absorption of heat. The local geography also plays a dominating role. The circumpolar current acts as a buffer preventing warm water from the tropics from transporting heat to the South Pole, a buffer that does not exist in the north. You can read some more details about that here.
Does it "balance out" in the end? Not really. Sea ice in the Arctic is reaching dramatic record lows. There are other components of the cryosphere that we can look at as well, permafrost, the Greenland ice sheet, global glacier mass, and these all carry the Global Warming signal.
One must look at the balance of evidence, not just those bits one likes. And this balance is clearly in agreement with all other indicators that warming is real and rapid.
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Comments View as Flat
wacki Posted 6:49 am
09 Nov 2006
explanation....
The reasons lie in the much larger amount of land in the northern hemisphere and the fact that the ocean's thermal inertia and ability to mix delay any temperature signal from the ongoing absorption of heat.
Did they explain this on RC? I don't remember this being clarified.
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Coby Beck Posted 8:06 am
09 Nov 2006
Pretty sure
I'm pretty sure that this came up on RC at least a couple of times...maybe if Andrew Dessler reads this he can provide an more authoritative confirmation!
Invent a clever saying, and your name will live forever! -- Anonymous
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wacki Posted 9:32 am
09 Nov 2006
found it......
The presence of a deep and circulating ocean component is key because ocean heat uptake increases most in the Southern Ocean as the climate warms (see Gregory 2000).
polar amplification
Heh, your way of explaining it is 1,000x better. As for the circumpolar currents, this image might come in handy:
Image link
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wacki Posted 9:45 am
09 Nov 2006
crappy search engine.......
I just did a search on real climate using the:
ttp://www.realclimate.org/index.php?s="SEARCH TERM"&submit=Search
hack. I found the word "circumpolar" in one and only one main post. And that post was not about polar amplification. Sometimes I wonder about those guys.
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Coby Beck Posted 11:42 am
09 Nov 2006
at least they try
yes, well, the gulf between scientists and the rest of us is hard for them to see! But kudos go to them for the fine effort RC makes, as I know you would agree.
Invent a clever saying, and your name will live forever! -- Anonymous
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wacki Posted 12:21 pm
09 Nov 2006
Re: at least they try
yes, well, the gulf between scientists and the rest of us is hard for them to see!
Heh, I am a scientist! I'm just in bio-tech and not climatology. But yes, I know what you mean. Heck I've given presentations that have gone over other peoples heads before. So I guess I'm a sinner too. :p
But kudos go to them for the fine effort RC makes, as I know you would agree.
Yes, I would agree. I did not mean to insult them. The guys at RC are world class researchers and even heroes IMO. I'm just glad there are people like you. Although I very rarely learn anything scientific from your blog posts I frequently learn a new way of communicating and bringing clarity to a concept. And that is just as valuable! So for that I consider you a world class communicator.
Keep up the great work.
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wacki Posted 2:37 pm
09 Nov 2006
clarification
"Although I very rarely learn anything scientific from your blog posts"
That's just because I read the RC forum first. :p
The unintentional jerk,
wacki
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Coby Beck Posted 3:46 pm
09 Nov 2006
don't sweat it!
Not to worry, I took it to mean that. I won't complain, not after all the other kind words!
Invent a clever saying, and your name will live forever! -- Anonymous
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grif Posted 5:01 pm
06 Jan 2007
Ice not increasing per NASA
>> Overall, it is true that sea ice in
>> the Antarctic is increasing.
Not true, according to this recent NASA study:
http://www.nasa.gov/home/hqnews/2006/mar/HQ_06085_arctic_...
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DaveR Posted 8:27 am
15 Feb 2007
Re. Ice not increasing per NASA
You've misunderstood the report you linked to, which is referring to total Antarctic ice mass, rather than to sea ice.
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dpercy Posted 9:10 am
04 Mar 2008
Antarctic and Arctic Sea Ice increases
Wow, the reasons the Global warming crowd through at us For more Sea Ice are just laughable. I'm a Sea Ice Forecaster in Alaska. there is at leat 33% more Antarctic Sea Ice than March 3, 2007. There was also an increase in 2007 from 2006 and maybe a minor one from 2005 to 2006. These so called climo experts say its due to warmer temps and water? Thats like telling me I'm cold because someone turned up the heat, or, my pop froze in the refrig beause I turned up the heat. How stupid do you think we are? The FACT is its getting colder. Antarctic cooling always begins first. You know the warmest earth year was 1998, 10 years ago. Maybe we have peaked the warming that began in the late 70s and now the earth is cooling. My gosh the Climo researchers might lose grant money over this. TWO more FACTS, Temperature rises always LEAD CO2 increases. Arctic sea Ice rebounded this winter to levels not seen, in some areas such as Iceland, in more than 40 years.
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dpercy Posted 9:22 am
04 Mar 2008
Total Ice vs Sea Ice
Sea Ice increases first, then Glacial, depending on precipitation. There is also a lag time from the warming to the cooling for ice increases. The recent warming ended in August 2005 and the cooling will increase further after about 7 to 10 years. Care to make a wager?
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Pangolin Posted 11:15 am
04 Mar 2008
Thermohaline oscillation?
I typed the following hypothesis before I googled but there seems to be partial validation here and here.
The situation with any temporary increase in Antarctic sea ice could be the result of a slowdown of thermohaline circulation. This is just a wild-ass guess but it would be possible for slowed thermal transport to result in local cooling.
While the amount of heat in the system is increased the amount available locally is always variable. Slowed thermohaline transfer of heat southwards from the tropics could result in temporary increases in sea ice cover while total systemic heat increases.
As mixing with the circumpolar current with the south pacific picks up warmer pacific waters this may reverse drastically. As on a smaller scale adding heat to one end of a fluid system could result in harmonic oscillation.
It's a very big system and the oscillation period could years but such oscillation would increase the thermal transport in the long run.
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rcglinsk Posted 5:44 am
24 Mar 2008
Hooray! Melt Arctic Melt!
Hooray for the melting of the Arctic! I call first dibs on the undersea oil and natural gas reserves. Also, I'm selling futures on good Newfoundland coastal spots for ports and fisheries. You all are just so confident the Arctic is going to melt. I wish I could share your optomism, but the future is hard to predict, and I'm cynical by nature.
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