Global Warming

[jethro]

jethro: the cooling of the central part of the Antarctic is consistent with a strengthening of the AAO; the Antarctic Oscillation. Because the continent is surrounded by ocean, there are no continental influence, as there are in the North. When it is 'strong' the AAO effectively creates a 'wall' of wind circulation which blocks incoming air (and thus warming). Another contributing factor is the ozone hole, which serves to suppress temperatures due to atmospheric heat loss during the relevant season; effectively, there is nothing to 'block' rising warmer air or reflect back what little heat there is.

This is consistent with what the climate models suggest should happen at this time, given the observed changes in the climate. Some people seem to believe that the 'cool' Antarctic is eveidence that the global climate isn't really changing, but this is not correct.

This is only a basic explanation, and ignores a lot of the complexities, but I hope it tells you what you need to know.

:)P

Thanks P3. I'm still concentrating on our artificial influence on C14; struggling to find anything because of the nuke connection and limited time to spend searching. I'm sure I've read somewhere that there are several areas of ozone thinning around the world; wonder if similar temperature anomolies occur there?

[Hiya]

Thanks P3. I'm still concentrating on our artificial influence on C14; struggling to find anything because of the nuke connection and limited time to spend searching. I'm sure I've read somewhere that there are several areas of ozone thinning around the world; wonder if similar temperature anomolies occur there?

My understanding, don't quote me on this, would be that in an ideal situation the upper troposphere would cool, and the surface temprature would warm, slightly. Although with so much CO2 going about both my warm more than expected.

[parmenides3]

Not just for jethro (but with his interest in mind), this absolute gem from the Journal of Biogeosciences:

http://www.biogeosciences.net/4/215/2007/bg-4-215-2007.html

It is an Open Access journal, so you can read the whole thing by clicking on the internal link at the bottom if you want.

It's about how much CO2 is added to the atmosphere from poo, (and landfill, but that's more boring).

The answer is: a lot! I won't spoil your fun by saying how much; RTFR

:)P

[BLAST FROM THE PAST]

Not just for jethro (but with his interest in mind), this absolute gem from the Journal of Biogeosciences:

http://www.biogeosciences.net/4/215/2007/bg-4-215-2007.html

It is an Open Access journal, so you can read the whole thing by clicking on the internal link at the bottom if you want.

It's about how much CO2 is added to the atmosphere from poo, (and landfill, but that's more boring).

The answer is: a lot! I won't spoil your fun by saying how much; RTFR

:)P

Hi P

Yes it has warmed over last 30 years but are we seeing a levelling off now?. It may or may not matter I don't know but I strongly believe that warmer oceans have lead to sea ice decrease not CO2 increase.

With the much higher levels of CO2 now and the fact the poles should be affected most the scenario is not fitting the bill. That is what concerning me, and non linear doesn't do it for me because the baseline for the recent warming was much higher than the baseline for the period leading up to the 30s and 40s.

Greenland and the arctic was warmer in the 30s and 40s and 85% of Antarctica has been cooling for 30-40 years. It cannot be the air temps melting the ice the 30s and 40s suggest not. Don't have sea ice records for back then but last year matched record minima so it hasn't been lower.

You know me I think cycles are more at play here and currently what I am seeing maintains that viewpoint....for now

Thanks for the link

BFTP

[parmenides3]

Hi BFTP: You have hit the nail on the head when you point out that there isn't much in the way of actual records for the Polar regions prior to the satellite era. Even the Arctic Climate Impacts Assessment made use of local Inuit/tribal testimony to evaluate past conditions. As an example of non-scientific evidence, it is pretty good compared to the normal, because of the long tradition of oral records and the heavy dependence on direct and learned experience to cope with the harsh conditions. But it shows how mittle data there is on which to base an accurate assessment of present conditions compared to the past.

It is pretty clear that the Poles go through decadal-scale climate shifts, from warm to cold and back again, but the mechanisms are still not fully understood. It is also pretty clear that the Arctic was in a different phase of the AO during the 30s-40s than afterwards.My understandng is that there was also a recognisable phase between the 70s-90s. Add to this the exceptional large natural, duirnal, seasonal and interannual variations, and it is easy to see why it is not straightforward to get a clear picture.

The sea-ice level is important, not so much for what it tells us about the Arctic, as what it is supposed to tell us about the entire climate system (Though of course there are connections).

I am not sure about what you mean by 'the poles being affected the most' by CO2-induced (or any other type) warming. The climate models suggest enhanced warming above 60N - S, in comparison to the mid-latitudes and the tropics, due to the larger difference in temps. to start off with, added to which is (in the Arctic), the known Northward progression of the ocean circulation, carrying more heat with it to the seas around the edge of the Arctic. (The way the Basin works is different - it is fed by the Bering Sea & changes are linked to pressure differences between the Aleutian and the Chuckchki areas, as well as the circulation pattern of the Beaufort Gyre).

I agree that cycles are at play, and this is one of the things which concerns me right now. The last time a large amount of ice was ejected Southwards through the Fram Strait, some years ago now, a lot of old ice was lost and replaced by younger, thinner ice. Since then, the internal circulation pattern of the Arctic has meant that ice has not flowed out of the Fram in the same way. Last month, a paper in GRL reported a measured change in the ocean currents, and concluded that, in all likelihood, the circulation was returning to the pattern which saw the previous one-off ice loss. This implies that something similar might well happen again in the next few seasons. If you add further loss from this to the existing picture of near-record lows for the past five years, plus global average temps being in the top five, plus North atlantic SSTAs being in the +3.5C area in some Northern latitudes already...

I am sure you get the picture.

It would be easy for me simply to say 'it is all caused by GW and CO2 is to blame', but in the case of the Cryosphere, to do this would be dishonest. It is probably the case, but by no means definite. It doesn't matter how you cut it, though, in the Arctic, there is less sea-ice than there used to be; it is declining by a measurable amount, and there is no indicator yet that this decline is likely to stop. If we knew what mechanism(s) were involved more clearly, we might be more certain. But I'm backing this year to be a new record low - I might even take bets on it.

I agree with the main point : in the cryosphere, sea temps probably play a bigger part in changes than air temps.

:)P

[BLAST FROM THE PAST]

Hi P

Nice reply. Lots to mull over and to agree with too. Lets see what happens this year it will be interesting as I think it was a pretty cool winter up there. My thoughts are that the oceans are still warming so I think there'll be further wear and tear.

BFTP

[Gray-Wolf]

Hi P

Nice reply. Lots to mull over and to agree with too. Lets see what happens this year it will be interesting as I think it was a pretty cool winter up there. My thoughts are that the oceans are still warming so I think there'll be further wear and tear.

BFTP

Even with a 'cold' season there is still a lot more 'single year ice' than ever before making it far easier to ablate before setting too on the multi-year ice pack. I have to think that GW (whatever the major driver) is the main reason for the excessive melt over the past 15yrs. The opening of the Polynya's last year went to highlight the basal erosion but also the intensification of the sub-polar currents bring warmer waters to the interior of the pack. Because the 'wound' of the Polynya was only dressed with single year ice I would not be surprised to see it open up again (and earlier) leading to a 'multiple edge' ablation of the ice between it and open water.......and more dark water means more warming.......

Edited April 30, 2007 by Gray-Wolf