Wednesday, March 2, 2011

The Nature of Arctic Sea Ice Lesson Series - 2

Polar ice basics
Due to the tilt of the earth's axis, the Arctic warms as the Antarctic cools and vice versa.  It appears as if the snow and ice are somehow transported from pole to pole during the course of a year.  In reality, each hemisphere has its own atmospheric circulation patterns, its own land-sea distributions and hence its own climatic variations.  Thus, there is a fairly large natural variability in the distribution of the planet's total amount of polar snow and ice.


Source: Wikimedia.

The annual melt at both poles is pack ice: sea ice.  It should not be confused with the older shelf ice which is bonded to land.  In general, the sea ice in the Antarctic melts and reforms every year.  By contrast, the Arctic sea ice melts and reforms by only a percentage annually and there is normally no long term trend.  Of recent decades there has been a definite and continual decadal trend towards more and more annual ice loss.

In that context, melting at one pole isn't news.  It happens every year.  But if the global amount of ice is shrinking, or if one pole is regularly losing ice mass over the years, that is a matter worthy of further investigation.

The Arctic sea ice extent at the end of the melt season continues to shrink.  No scientific theory has been put forward to suggest a mechanism by which the ice might reverse that trend this year.  Within that context, let us examine what people have been saying recently about the Arctic.


A small sample of recent news reports
Melting Arctic Ice: What Satellite Images Don't See
Jan. 28, 2010, Michael D. Lemonick, time.com

... as Barber and his colleagues explain in a recent paper in Geophysical Review Letters, the analysis of what the satellites were seeing was wrong. Some of what satellites identified as thick, melt-resistant multiyear ice turned out to be, in Barber's words, "full of holes, like Swiss cheese. We haven't seen this sort of thing before."


Scant Arctic ice could mean summer "double whammy"
Feb. 4, 2010, Deborah Zabarenko, Environment Correspondent, WASHINGTON
Reuters US reuters.com
Scant ice over the Arctic Sea this winter could mean a "double whammy" of powerful ice-melt next summer, a top U.S. climate scientist said on Thursday.


Arctic ice increased during freezing winter
Apr. 4 2010 , Alastair Jamieson, telegraph.co.uk
Unusually cold weather, caused by the same patterns that have given Britain its coldest winter for decades, has resulted in levels of ice cover in line with longer-term averages for the first time since 2001.


Arctic ice recovers from the great melt
Apr 4, 2010, Jonathan Leake, Environment Editor, timesonline.co.uk
IF you thought it was cold in Britain for the time of year, you should see what is happening around the North Pole. Scientists have discovered that the size of the Arctic ice cap has increased sharply to levels not seen since 2001.

Arctic winter ice recovers slightly despite record year low, scientists say
7 April 2010 Juliette Jowit guardian.co.uk
Figures from the National Snow and Ice Data Centre indicate six or seven- year low over past three decades


Recent reports on the state of the Arctic sea ice cover range from 'some recovery' all the way through to ' recovery to extent not seen since 2001'.

There is a world of difference between 'extent' and 'mass'.  Consolidation, a major factor in the overall resistance of sea ice to melting, also needs to be considered.  Overall geographical extent takes no account whatsoever of thickness, much less consolidation.

Recent reports on Arctic sea ice recovery were based on a 'blip', arrowed in red below, on a chart of sea ice extent of at least 15% coverage and with no reference to thickness.  By definition, 15% sea ice is raft ice - it is not consolidated ice.

Apr. 4 2010, area of Arctic ocean with at least 15% sea ice extent.
Source: http://nsidc.org/arcticseaicenews/


An aside on reportage
Since about 1910 we have lived in an age of ever-increasing division of labor.  As we rely more and more on the skills of others we need ever fewer skills ourselves.  Many people can't change a tap washer, a fuse or a spark plug.  They rely on others to exercise the required skills with due diligence.  Unfortunately, many people adopt that attitude with news.  Just about anybody would agree that there are good and bad mechanics, electricians and plumbers.  Is it so hard to accept, then, that there are good and bad reporters?  But how to tell them apart?

A conscientious worker will show you the new part, show you the part replaced, explain why it needed replacing, put that in writing and give you an itemised bill.  A bad workman will sell you a bill of goods.  Asked for the old component a bodger will claim to have thrown it away.  Bodgers don't like evidence.

A good reporter will cite sources in sufficient terms that any interested reader can find the original report or data.  A bad reporter will either not cite sources, or, citing a single scientist will use plural terms such as 'scientists say'.  Climate agendists do this a lot.  By telling the public that 'scientists say' such and such, they give a false appearance of general agreement amongst scientists.


A few more recent reports and blogs
Arctic ice scare seems to be history
Apr. 8 2010 Barry Brill, gisborneherald.co.nz
The size of the Arctic ice cap has increased sharply, to comfortably reverse the “great melt” of 2007, and extending coverage over a vast area of the Arctic Sea, to levels not seen since 2001.

Scientists emphasise the fluctuations of ice in the Arctic are natural variations in weather which have little relevance for long-term climate change.
    ...
    The Earth has two poles, and for reasons which are not well understood, when one pole warms, the other pole cools.
    ...
    With Arctic sea ice back to normal, the oft–mentioned threat to polar bears seems unlikely to eventuate.

Brill: "reasons which are not well understood".
Peary: 
"Every school boy learns that at the two ends of the earth the year is composed of one day and one night of equal length, and the intervening periods of twilight; but the mere recital of that fact makes no real impression on his consciousness. "


Climate Cools But Arctic Ice Scares ContinueDr. Tim Ball  Monday, January 18, 2010, canadafreepress.com, climatechangefraud.com,grendelreport.posterous.com and many other blogs.  I have already written about Tim Ball's Nonsense On Ice.  No need to repeat my analysis here.

Tim Ball is a frequent poster on climaterealists.com, as is Piers Corbyn of weatheraction.com.

Piers Corbyn thinks that global warming is over.  He has a theory - which he won't reveal in detail -  that the sun causes all climatic events.  He makes weather predictions and claims audited successes, but doesn't name the auditors.  He rather likes what Lord Monckton and Marc Moranohave to say about climate science.

------------------------------------------------------

There we have it - lot's of views on the Arctic, and on global climate in general ranging the full spectrum from caution to beyond the the fringes of science.

What is the reality?  
In the third part of this short series - Arctic Ice 2010 #3 - The State Of The Ice - I describe the state of the Arctic ice as of April 09 2010.  I show lots of evidence, so that you can decide who to trust amongst the writers on climate science quoted above - and amongst many others.


Continued on next post

No comments:

Post a Comment