Monday, September 01, 2008

Arctic Ice Growth: How Much?

This link (Arctic Ice Growth: How Much?) is rather relevant to the snippy little exchange of comments that I have had with a reader named PKD re the NSIDC and BBC's reportage thereof.

I think the important point in the article is the selection of the time period over which comparisons are made. Selecting the past 30 years of temperature and ice records captures the warming trend that ended the cooling from 1940 through the late 1970s.
Is it possible that the 30 year satellite record coincidentally represents only one leg of a waveform? Greenland temperature records would hint at that. If you examine only one leg of a waveform, you will absolutely come to the wrong conclusion about the long term behaviour - just as some did during the 1970s ice age panic.

9 comments:

PKD said...

Aah yes - Steve Goddard.

The buffoon went public publishing his claim that there was really over 30% more ice than NSIDC suggest before checking it with them, and his article was picked up by various esteemed publications such as, um, The Register.

http://www.theregister.co.uk/2008/08/15/goddard_arctic_ice_mystery/

Cue one weeks worth of comminique's b/w Goddard and the NSIDC and he produced a mea culpa - yep the NSIDC data was right and Goddard was, well, talking out of his butt. See the editors note at the bottom of the link complete with Goddard's retraction.

So I'd rather say that actually the significant thing in your link Half is your deferrence to someone who by all readings of his blog, is an out and out denialist pretending to be a sceptic scientist.

Still I suppose you must all stick together hmmm?

Halfwise said...

You haven't answered my question about the causes of this year's extent of Arctic Ice. Step up, PKD.

The point I highlighted from Goddard's article was the folly of focusing on a time period that coincides with one leg of a waveform, so while you are at it, you could enlighten us on why that is bad science too.

PKD said...

To answer your oh so innocent question Half firstly there is nothing about Climate Change that states that year-on-year the ice will always be less than the previous year.

It's the climatic average (over 21 years in NSIDC's case) that is gradually receding, which it will do this year given the ice is only slightly off the all-time low of last year, as opposed to being above average.

Once the ice 'growth' goes above the CLIMATIC average for the time of year, well then we'll have some good news worth celebrating.

Until then we have the rather depressing staistic of the 3 lowest ice levels in just 4 years helping push the climatic average down, which sorry to say supports AGW theory...

Hope that helps anyway.

Halfwise said...

PKD I commend you on stating the basis for your comments. A 21 year trend is not a trivial thing.

My opinion is different; the 30 year trend that had me convinced as a student climatologist in the 1970s that the ice age was coming turned out to be one leg of a longer cycle. I think today we are seeing the other leg. CO2 fails to explain any of the periodicity over the past 10,000 years.

I don't think 21 years explains much, you do. Vive la difference.

PKD said...

CO2 fails to explain any of the periodicity over the past 10,000 years.

And nor should it! Obviously the main point of AGW is that CO2 has only become an issue since the Industrial Revolution. Before then it's been much more constant over that period.

And yes, climate is obviously determined by many factors and CO2 is only one, which is why there is nothing wrong with naturally occuring periodicity and cycles.


But FWIW try telling Western Australians that measuring climate over only 21 years is meaningless or doesn't explain much - given the climate change there has shifted the rain patterns much further to the North forcing them to desalinate I think they'd tell you the effects of climate change can happen much more quickly than 10000 years in their region.

Halfwise said...

PKD
I would neither dismiss the suffering of Western Australians in the past drought nor the suffering of Canadians and Americans in the 1930s. Drought is an awful thing. In Canada there is still debate about whether the dry areas of the prairies were settled during an unusually wet period, leading people to believe that the natural conditions would support agriculture when in the long run perhaps they can't.

But it is a real stretch for me to pin a drought on CO2 emissions and then to imagine that reducing CO2 will bring things back to normal. That chain of causalities is not strong enough for me.

If temperatures are higher than ever and if Anthro CO2 is a significant contributor and if nothing in the environment damps CO2 concentrations then one has to consider whether warmer temperatures and higher CO2 are a bad thing or a good thing. Even if we wanted to do something, no one other than Bjorn Lomborg has done much cost-benefit analysis of the suggested remedies. I am far from convinced that the popular path is the right one.

PKD said...

one has to consider whether warmer temperatures and higher CO2 are a bad thing or a good thing.

If the higher CO2 was released naturally then it would be a 'good' thing in that it would be natural. Higher CO2 created by *pollution* on the other hand would not. The main tenents on this whole argument is that,

i) Mankind should not artifically change the climate, especially given
ii) The odds of the overall effects of the change being globally detrimental far outweigh the odds of it being beneficial.

In case you hadn't noticed, mankind does not have a good track record when it comes to changing eco-systems - they generally end up worse off!

Halfwise said...

>Mankind should not artifically change the climate

It's a bit late for that. Every field that is planted, every forest that is cleared, every meadow that is paved over has measurable, directly attributable impacts on local climate whose regional effects are far greater than CO2 ever will be. Climatologists do not all write good models, but they do understand the effect of land use on climate. This is why climatology is found in geography departments not physics departments at universities.

Is CO2 a non-factor in climate? Probably not, I will grant you. But it is so far down the list of important things to worry about that I can only marvel at the air time it gets these days. Take half the AGW research money and put it into water-quality and water supply research and you will see some real benefits to mankind.

We impact the planet by being here. So do ants; we just happen to be more dominant as a species. We have a duty to our environment but we have an obligation to our fellow humans that is equal in importance. It appalls me that we waste good research money on questionable but popular priorities.

PKD said...

Every field that is planted, every forest that is cleared, every meadow that is paved over has measurable, directly attributable impacts on local climate whose regional effects are far greater than CO2 ever will be.

So you do at least agree that mankinds activities impacts and changes the climate? Well at least that's a start! ;)