August - global weather notes

[RWood]

NCDC: Climate of 2007 - August Global Analysis

Some sobering stuff here.

[ATO2]

Originally Posted by RWood

NCDC: Climate of 2007 - August Global Analysis

Some sobering stuff here.

For sure. Looks as if many of the politicians are still burying their heads in the sands of hope!

[Grant]

An interesting split between the land temps of the Northern and Southern hemispheres too.

[ATO2]

Originally Posted by Grant

An interesting split between the land temps of the Northern and Southern hemispheres too.

Am I right in assuming that this simply because of our large area of surrounding ocean compared to the northern hemisphere? That this is a time lag and that eventually, in the future, our hemisphere will show land temperatures increases more in line with the northern one?

[RWood]

Originally Posted by ATO2

Am I right in assuming that this simply because of our large area of surrounding ocean compared to the northern hemisphere? That this is a time lag and that eventually, in the future, our hemisphere will show land temperatures increases more in line with the northern one?

I think that's correct, even if it takes quite a long time. It's a complicated matter, of course. I know there are for example "post-CFC" issues with the Antarctic polar vortex. I'll look for a comment I saw from an Australian meteorologist to elaborate on this a bit.

[RWood]

I found this from another forum, comment by a meteorologist, arguing against people who are trying to deny warming by any available means - it at least gives an explanation of why the Antarctic interior has not warmed over the last couple of decades [of course the "deniers" use this fact to twist the story]. I don't think he'd mind it being requoted here.

The ozone hole holds a number of lessons. First the cost of fixing it was trivial - the polluters massively exaggerated the cost. Secondly, atmospheric scientists by way of their conservatism took a look time to raise the alarm. They couldn't believe what they were seeing, and it took a long time before the science was confident enough to establish the CFC-ozone link. Third, its DUMB luck that saved the earth from unimaginable destruction with CFCs. Cl is a relatively poor catalyser of ozone destruction but Br is far far more effective. It was only because of dumb luck and the fact that Cl is a bit cheaper than we used it instead of Br in our CFCs. If this didn't happen, the ozone hole would now be global - a life would be???.

Finally, there have been totally unexpected consequences. The major one is that ozone depletion has completely changed the southern hemisphere polar votex in spring/early summer as it has massively increased the upper tropospheric baroclinicity. As a result the westerlies are much stronger at high latitudes and the polar lows stronger. This has meant very rapid warming in sub-polar latitudes (including the Antarctic peninsula) and a lack of warming over the pole over the last 20 years.

The stronger westerlies mean that the pole has been insulated from global warming and sea ice in the Antarctic after rapid retreat up to around the 1970s has been stationary (this is probably due to enhanced northward drift of sea ice due to Ekman drift). No body saw this coming....

Sounds like a good thing - but problem is as ozone recovers the 1C of warming which has been hidden will hit the continent with a bang on top of any other AGW warming this century. There's also some evidence that part of the reason the subtropics of the southern hemisphere have dried out since the 1970s is also due to ozone depletion pulling the polar storms south (as must happen to conserve angular momentum).