Here is the melting glacier chart from right up front on page 18, in the section on sea level rise (ironic, since if you really read the IPCC report closely, sea level rise comes mainly from thermal expansion of the oceans – glacier melting is offset in most models by increased snow in Antarctica**).

Wow, this looks scary.  Of course, it is clever chartsmanship, making it look like they have melted down to zero by choice of scale.   How large is this compared to the total area of glaciers?  We don’t know from the chart — percentages would have been more helpful.

Anyway, I could criticize these minor chartsmanship games throughout the paper, but on glaciers I want to focus on the selected time frame.  What, one might ask, were glaciers doing before 1960?  Well, if we accept the logic of the caption that losses are driven by temperature, then I guess it must have been flat.  But why didn’t they show that?  Wouldn’t that be a powerful chart, showing flat glacier size with this falloff to the right?

Well, as you may have guessed, the truncated time frame on the left side of this chart is not flat.  I can’t find evidence that Meier et al looted back further than 1960, but others have, including Oerlemans as published in Science in 2005.  (The far right hand side really should be truncated by 5-10 years, as they are missing a lot of datapoints in the last 5 years, making the results odd and unreliable).

OK, this is length rather than volume, but they should be closely related.  The conclusion is that glaciers have been receding since the early 19th century, LONG before any build-up of CO2, and coincident with a series of cold decades in the last 18th century  (think Valley Forge and Napoleon in Russia).

I hope you can see why it is unbelievably disingenuous to truncate the whole period from 1800-1960 and call this trend a) recent and b) due to man-made global warming.  If it is indeed due to man-made global warming since 1960, then there must have been some other natural effect shrinking glaciers since 1825 that fortuitously shut off at the precise moment anthropogenic warming took over.  Paging William of Occam, call your office please.

Similarly, sea levels have been rising steadily for hundreds, even thousands of years, and current sea level increases are not far off their average pace for the last 200 years.

** The climate models show warming of the waters around Antarctica, creating more precipitation over the climate.  This precipitation falls and remains as snow or ice, and is unlikely to melt even at very high numbers for global warming as Antarctica is so freaking cold to begin with.

Now, the authors might object to that and say, “we don’t believe that.”  But in fact they must, since in the report, any US climate trend in the last 20 years (more rain, less rain, more storms, fewer storms, more snow, less snow, etc) is all blamed on man.   Why else discuss a given trend in climate in a report on man-made climate change except to create the impression that each and every trend in climate is due to man, and can therefore be extrapolated a hundred years in to the future?

I am going to take on many of these charts in this series, but here is an example from page 30:

So what?   Do you really think there is a single 50-year period in the history of North America where you wouldn’t see this kind of effect?  Where, sans man, the chart would be all white with no changes?  And even trying to pull regional conclusions out of this is almost impossible — for example, the brown in the Southeast is heavily driven by the 2008 endpoint with a big drought.  Shift the period by even a few years and the chart has the same mixture of blue and brown, but distributed differently.

Of course,this assumption of underlying stability is absurd.  History is full of short, medium, and long-term climate cycles.  An honest scientific discussion would look at the degree of variation over time, say hundreds or thousands of years, and then put recent variations in this context.  Are recent changes unprecedented, or not?  Well, we’ll never know from this report.

I guess this may be an interesting exercise in probability theory for autocorrellated functions, but that is about it.  I mean, does anyone really doubt that there has been some sort of upward trend in world temperatures?

More relevent are the questions

• Is this upward trend unique or is it within the range of normal natural fluctuations?
• Is this trend exaggerated by upwards biases in surface temperature measurements?
• What proportion of this trend is due to anthropogenic factors (e.g. Co2) and what proportion is due to natural variations (e.g. unusually strong solar cycles in late 20th century)?
• How can one reconcile the trend over the last 100 years with climate models, which use assumptions that imply that past warming should have been much higher?

Also, the Arctic has been the hot spot of the world over the last 30 years or so:

Increasing far more than global averages:

So the question is not necessarily why Arctic Sea ice continues to retreat – this appears part of a long term trend that in fact pre-dates things like, say, man’s production of substantial amounts of CO2.  But the more worrisome question has been, why has this retreat seemed to have accelerated the past several years:

Its hard to fully correlate recent activity with Arctic temperatures.  In fact, in the last three or four years (see above) we have seen decreasing Attic temperatures, not increasing ones.  But never-the-less, this ice picture is often used as exhibit #1 to prove anthropogenic warming.  The "tipping point is near" cry supporters of the theory that Earth’s climate, unlike nearly every other long-term stable natural system, is dominated by positive feedback (and ignoring anecdotal evidence that the Arctic experienced similar melting in the 1930s).

Well, last year, there was some preliminary findings form NASA that said that the unusual low ice pack in 2008 may have been due to shifting wind patterns.  Now, Anthony Watts points us to two new studies that both conclude something other than global warming and CO2 may be behind recent ice pack trends in the Arctic.

Observations over the past decades show a rapid acceleration of several outlet glaciers in Greenland and Antarctica¹. One of the largest changes is a sudden switch of Jakobshavn Isbræ, a large outlet glacier feeding a deep-ocean fjord on Greenland’s west coast, from slow thickening to rapid thinning² in 1997, associated with a doubling in glacier velocity³. Suggested explanations for the speed-up of Jakobshavn Isbræ include increased lubrication of the ice-bedrock interface as more meltwater has drained to the glacier bed during recent warmer summers⁴ and weakening and break-up of the floating ice tongue that buttressed the glacier⁵. Here we present hydrographic data that show a sudden increase in subsurface ocean temperature in 1997 along the entire west coast of Greenland, suggesting that the changes in Jakobshavn Isbræ were instead triggered by the arrival of relatively warm water originating from the Irminger Sea near Iceland. We trace these oceanic changes back to changes in the atmospheric circulation in the North Atlantic region. We conclude that the prediction of future rapid dynamic responses of other outlet glaciers to climate change will require an improved understanding of the effect of changes in regional ocean and atmosphere circulation on the delivery of warm subsurface waters to the periphery of the ice sheets.

The scientists said their data showed that significantly warmer periods and significantly colder periods had occurred during the last interval between glacial epochs, about 115,000 to 135,000 years ago. They said they could not tell whether that meant similar changes were in store. Their findings were reported today in two papers in the journal Nature. [...]

The new studies found that the average global temperature can change as much as 18 degrees Fahrenheit in a couple of decades during interglacial periods, [Dr. J. W. C. White of the Institute of Arctic and Alpine Research of the University of Colorado] said. The current average global temperature is 59 degrees Fahrenheit. …

At one point between the last two glacial epochs, the climate melted enough polar ice to raise sea levels some 30 feet. As noted by a member of the drilling team, Dr. David A. Peel of the British Antarctic Survey, it was so warm in England that hippopotamuses wallowed in the Thames and lions roamed its banks….

In his commentary, Dr. White wrote: "We humans have built a remarkable socioeconomic system during perhaps the only time when it could be built, when climate was sufficiently stable to allow us to develop the agricultural infrastructure required to maintain an advanced society. We don’t know why we have been so blessed, but even without human intervention, the climate system is capable of stunning variability.

Well, it seems that those of use who were offended by the notion of a long-term stable natural process being dominated by positive feedback may have been right after all (via Tom Nelson):

Cirrus clouds are performing a disappearing act which is taking scientists by surprise.

In the global warming debate, it is assumed that temperature rises will lead to more rainfall, which in turn will see an increase in high-altitude cloud cover that will trap infrared heat.

But research on tropical climate systems has found the opposite is happening, with cirrus clouds thinning as the air warms, leading to rapid cooling as infrared heat escapes from the atmosphere to outer space.

Rank:	Name / Areas of Largest Loss:	Year:	Ocean Area:	Deaths:
1	Great Bhola Cyclone, Bangladesh	1970	Bay of Bengal	550,000
2	Hooghly River Cyclone, India and Bangladesh	1737	Bay of Bengal	350,000
3	Haiphong Typhoon, Vietnam	1881	West Pacific	300,000
3	Coringa, India	1839	Bay of Bengal	300,000
5	Backerganj Cyclone, Bangladesh	1584	Bay of Bengal	200,000
6	Great Backerganj Cyclone, Bangladesh	1876	Bay of Bengal	200,000
7	Chittagong, Bangladesh	1897	Bay of Bengal	175,000
8	Super Typhoon Nina, China	1975	West Pacific	171,000
9	Cyclone 02B, Bangladesh	1991	Bay of Bengal	140,000
10	Great Bombay Cyclone, India	1882	Arabian Sea	100,000
11	Hakata Bay Typhoon, Japan	1281	West Pacific	65,000
12	Calcutta, India	1864	Bay of Bengal	60,000
13	Swatlow, China	1922	West Pacific	60,000
14	Barisal, Bangladesh	1822	Bay of Bengal	50,000
15	Sunderbans coast, Bangladesh	1699	Bay of Bengal	50,000
16	Bengal Cyclone, Calcutta, India	1942	Bay of Bengal	40,000
17	Canton, China	1862	West Pacific	37,000
18	Backerganj (Barisal), Bangladesh	1767	Bay of Bengal	30,000
19	Barisal, Bangladesh	1831	Bay of Bengal	22,000
20	Great Hurricane, Lesser Antilles Islands	1780	Atlantic	22,000
21	Devi Taluk, SE India	1977	Bay of Bengal	20,000
21	Great Coringa Cyclone, India	1789	Bay of Bengal	20,000

Oddly uncorrelated with atmospheric temperature or CO2, huh?  In fact, three of the four most recent occured in the seventies, a time known for its cooling.  Two of the top five occured around the period of the little ice age.

What is normal?  One other thought.  I have often asked, vis a vis climate, the question "What is Normal?"  Because of the quality of observation by sattelites, we tend to define normal by what we have observed since about 1979, when the first satellites began gathering relevent global climate data.  For example, when news stories last year said the Arctic sea ice was at "an all time low," they actually meant the lowest point since satellites began observing the ice c.1979.  "All time" meant the last 30 years.  Note that only one of these 22 storms occured in the last 30 years.  By defining "normal" as the last 30 years, we would in this case miss over 95% of the severest storms.  Even defining "noral" as the time since 1900 would cause us to miss 7 of the top 10 storms.

Spot the correlation:  Do you see a correlation in this list?  How about with poverty?  When cyclones hit US low-lying coastal areas and drive flooding up river valleys and deltas (think Katrina) we get a few hundred or at most a couple of thousand deaths, at most.   A tragedy for sure, but Katrina did not even kill 10% of the people killed by the bottom storm on this list.  What is the difference?  Poverty.  From this data table, which option makes more sense:

1. Reduce CO2 and perhaps ocean temperatures by a few tenths of a degree, in the process limiting economic growth and increasing poverty.
2. Burn all the fossil fuels we can on the path to helping people in Bangladesh and China and India become wealthier.

I am sure I know which would save more lives.

The Pacific Decadal Oscillation (PDO) is a temperature pattern in the Pacific Ocean that spends roughly 20-30 years in the cool phase or the warm phase.

In 1905, PDO switched to a warm phase.
In 1946, PDO switched to a cool phase.
In 1977, PDO switched to a warm phase.
In 1998, PDO showed a few cool years.

In 2008, PDO seems to be switching to a cool phase. (NASA).

The warm (cool) phase is determined by above-the-average (below-the-average) temperatures along the West Coast of the U.S. and Canada.

At the same time, a longer cycle occilation in the Atlantic called the AMO may also be in the cooling part of its occilation over the next decades.

Though from what I read, the PDO mainly affects temperatures around the Pacific Rim, the Pacific is in fact  a very large part of the earth, so I wondered if its cylcling might have some correlation with world temperatures:

Well, that is kind of interesting.  Note by the way I use the GISS surface data in this chart, so one can assume the warming in the last 20 years is overstated for a variety of reasons we have discussed on this site.  Never-the-less, it is interesting.  A few thoughts:

• Catastrophists are spinning that the PDO cool cycles just delay or suppress man-made warming signals.  OK.  But if you argue this, you have to also argue for the converse — that the PDO exaggerate what might be man-made warming signals during its warm cycles.  Catastrophists and in particular the IPCC, however, said that all of the post 1977 warming was due to man – I don’t remember anyone mentioning "PDO" in these discussions (In fact, they argue that some additional warming was being masked).  Catastrophists love to point to natural cycles only when they can be claimed to mask man-made warming.
• I am constantly amazed at how much the 1905-1947 trend on this chart looks like the 1977-2005 trend.  But here is the amazing thing to me:  Catastrophists as well as the IPCC claim that these trends had different causes.  In fact, you MUST believe they had different causes to believe the AGW story (since there was little man-made CO2 in the first period).  In other words, to belive the catastrophic man-made global warming theory, you have to believe some effect, presumably natural but never identified by the IPCC, drove temperatures through 1947 and then switched off, never to return, at the exact same moment that man began producing CO2 in earnest.

Update:  It may be too early to tell if the PDO is doing a major or sort of minor shift, but the past frequency seems to indicate we will see a shift soon.