Oceans to blame for ice shelf collapse? 25 February 05

Of the world, and/or specific areas after high end projected sea level rise by 2100, & 2200, then we could show people…

We need to be getting displays ready for Earth Day. My GW display has 3 panels in cartoon-exaggerated form. 1) CAUSES: a drawing of the earth & sun, with rays coming from the sun going through an atmospheric layer on which I’ve written CO2, CH4, NOX, CFCs, etc, hitting earth, bouncing back to the layer, then bouncing back to earth; I also have drawings with cars and smokestacks with billowing gray puffs coming out. 2) CONSEQUENCES: I show Florida about 1/2 submerged under water, with the outline underwater of the present Florida; a gigantic insect and a giant weed about to devour a tiny grain plant (studies show plants will grow larger in a CO2 atmosphere, but weeds will outstrip food crops & the crops will be less nutritious, causing insects to eat a lot more); a giant tornado with the words “severe & frequent storms”; and an emaciated African madonna & child, with the words “severe droughts.” 3) SOLUTIONS, with pictures of wind generators, efficient car (with tiny gray emissions-puff), mass transit, clothes line, CF bulb, SunFrost frig, etc.

Better to keep it simple, so people can look at the drawings & understand. Then also have a more detailed tri-fold pamphlet that explains in more detail, with lots more solutions.

The retreat on glaciers/ice caps is indeed not necessarily always connected to warming and could be natural. Alpine glacial retreat is conected to changes in the north atlantic oscillation (NAO), just as growing glaciers in scandinavia are the corresponding result of NAO variance.

However glacial retreat on for example Mt Kenya/ Kilamanjaro has to be a warming signal, as no such weather oscillation exists which would affect snow fall patterns. (ENSO is too longterm and remote to directly affect)

There are always going to be examples that may question the theory. There are too many more which prove it.

Is there really any hope that what is occurring in Antarctica may be caused by some natural climate oscillation?

It seems to me at this point that no one knows enough with regard to climate yet we must make prudent decisions regardless based on the risk.

We have to do give our best effort in the face of this uncertainty which provides us no guarantee for success.

What is your best assessment of the future Antarctica, the cause and effect, and if we can do anything about it?

Or is it just a BIG unknown at this time whereby anything can happen at any time and we just have to live with that prospect.

I ask just in case you might be able to provide us more insight.

Best, Dan

Brendon, the NAO changes in themselves don’t change glacial mass balance. The resultant weather pattern changes make the difference – warming, less precipitation, etc.

Second, there is good evidence the Kilimanjaro glacial retreat is due in part to changes in precipitation brought about by deforestation – human changes. Certainly there may be some warming involved.

But your conclusion is correct that there is plenty of evidence that anthropogenic causes are likely largely to blame for current climate conditions.

Best,

D

Hi

I thought that it would be understood by implication, the NAO variance impacts on warming/precipitation. Apologies for not making myself clear.

I am interested in the other possible causes for east african glacial retreat.

Could you forward me any links/info on where this information/research comes from. It could be relavant to other areas too.

many thanks

Brendon

I’m not sure why you’re trying to identify specific mechanisms in specific areas. Tropical glaciers are retreating across the Andes, West Papua and East Africa. As are mid-latitude glaciers. It’s a global phenomenon, which must have a global causal mechanism driving it. That is clearly the increase of temperatures – there has been no global fluctuation of precipitation to drive this. For a good visual view of global mass balance, see the World Glacier Monitoring Service graph. See blog post above.

Mark, it was a direct reply to another poster. I addressed specific items in that particular post I replied to. I’m well aware of differing mechanisms – viz. Kilimanjaro and precipitation changes, most likely brought on by deforestation.

The point is anthropogenic changes can take more than one form, which has implications for policy-makers.

HTH,

D

No problem, Brendon, I could have been reading too closely as well. Here’s some stuff that may be helpful:

1. Molg T, Hardy DR 2004. Ablation and associated energy balance of a horizontal glacier surface on Kilimanjaro. Journal of Geophysical Research-Atmospheres 109:(D16) Art. No. D16104.

Attempts to explain precipitation variability on K.

2. Kaser G, Hardy DR, Molg T, Bradley RS, Hyera TM 2004. Modern glacier retreat on Kilimanjaro as evidence of climate change: Observations and facts. Int Journ Clim 24:3 pp. 329-339.

Re-write of above, more detail about precipitation.

3. Hastenrath S 2001. Variations of East African climate during the past two centuries. Climatic Change 50 (1-2): 209-217.

Says not really sure why E Africa got drier and warmer, but sort of coincident with New Guinea and Andes.

4. Molg T, Hardy DR, Kaser G 2003. Solar-radiation-maintained glacier recession on Kilimanjaro drawn from combined ice-radiation geometry modeling. Journal of Geophysical Research-Atmospheres 108:D23 Art. No. 4731.

Uses a model to recreate climate since 1880 and concludes solar radiation is main culprit (note authors).

5. Thompson LG, Mosley-Thompson E, Davis ME, Lin PN, Henderson K, Mashiotta TA 2003. Tropical glacier and ice core evidence of climate change on annual to millennial time scales. Climatic Change 59:1-2 pp. 137-155.

Looks at Himalaya, Andes, more and finds warming at low latitudes, much of this is driver for some areas, last sentence of abstract has good phrase: The isotopic composition of precipitation should be viewed not only as a powerful proxy indicator of climate change, but also as an additional parameter to aid our understanding of the linkages between changes in the hydrologic cycle and global climate.

We know precipitation patterns and events are changing – the mean amounts may be the same, but precip is more episodic in the interiors of many continents.

HTH,

D

very grateful for the citations Dano. By the way your profile says you are a planner, what kind?

regards

Brendon.

Yer welcome, sir. Any time.

I’m a city planner. Environmental Planning specialization for my Master’s. I try to improve human ecology by lessening the amount of concrete in cities, either exposed to the air by covering with trees, or replacing/remaining in plants. Hopefully, happy humans are more aware of their environment and will seek to protect it.

Best,

D