What The IPCC Said About Glaciers In 1990
April 25, 2017
By Paul Homewood
When we talk about glaciers retreating, it is worth recalling what the first IPCC Report in 1990 had to say about the matter:
http://www.ipcc.ch/ipccreports/far/wg_I/ipcc_far_wg_I_full_report.pdf
In other words, glaciers began receding in the second half of the 19thC, and the fastest rate of retreat was 1920-60, before CO2 emissions could have had any significant impact.
The IPCC also added the following chart showing how, on a range of glaciers, rapid retreat began in the 19thC.
They also added:
And:
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NOT A LOT OF PEOPLE KNOW THAT 
An interesting piece Paul. I am aware that the likes of Tyndall and Agassiz remarked on the considerable retreat of the Rhone Glacier. That would have been around 1870 so presumably there was a period of fast retreat before the trace shown in your figure 7.2. It would be interesting to compare these IPCC quotations with their tune in later reports. I would guess that political interference before publication may have given a quite different interpretation.
A great article – of course like any large mass, glaciers take time to respond to changes in heat. (Goes away to work it out)
OK because it’s complex – time for waffle. The simple answer is that thermal diffusivity is not that different to rock. The other way to answer the question is “what happens to temperature change following a sinusoidal at the surface)
If the temperature were to vary as a sinusoidal with period 100years, The temperature at approx 25m deep would be 1/2 that of the surface. The temperature at 60m would be delayed by 25years.
Due to some oddities in the way heat penetrate objects… (don’t blame me it’s the physics)
If that sinusoidal were 1000years long, it would be 1/2 amplitude at ~80m and delayed by 250years at 190m deep.
But if 10,000 years long, heat at around 250m would be responding to half the surface change and it would be delayed by 2500years at 600m deep.
So in rough terms (ignoring water flow through the ice) the ice of a glacier about 100m deep is responding to temperature changes that were occurring around 50-100years ago.
OK this answer is now written up in slightly more detail on my blog (with a pretty graph): http://scottishsceptic.co.uk/2017/04/25/delayed-melting-of-glaciers/
‘before CO2 emissions could have had any significant impact’
If indeed they have ever had any ‘significant impact’, given that CO2 is only a trace gas in the atmosphere (0.04%), only a third of which has appeared in the period in question.
I don’t see why you’d assume that glaciers retreat simply by melting. Wouldn’t they be governed by a “mass balance” whereby new snow increases their mass and melting decreases it? If so, a glacier could retreat if its melting rate was unchanged as long as the relevant precipitation rate declined. No?
We visited Canada and the Athabasca Glacier area in the early 1970s. Crossed a small bridge to the ice front in the morning. A few hours later water covered the bridge to 8 cm. The ice front was dark with small rocks and grit. Great experience.
“Around 1800, the Athabasca Glacier peaked, then went through a period of recession, and then advanced again until 1840, when it began receding until the present day.”
https://www.triposo.com/loc/Columbia_Icefield/history/background
Lat/Long near the “toe” of Athabasca Glacier — at the parking area:
52.21254, -117.23275
‘advanced again until 1840’
Tambora 1815 – ‘the link between the post-eruption climate changes and the Tambora event has been established by various scientists’
http://en.wikipedia.org/wiki/1815_eruption_of_Mount_Tambora
This is IPCC 1990 when they openly talked about the Little Ice Age and the Mediaeval Warm Period – the famous Fig 7.1(c) is on the facing page to Paul’s Fig 7.2 on glacier termini, unattributed, as many have remarked. I believe Steve McIntyre did a forensic analysis of where it may have come from and who produced it (links etc gratefully received). I don’t believe it is in Lamb, who was equivocal about the MWP being a global phenomenon because he didn’t have sufficient historical info except from NW Europe.
As most here know, the LIA and MWP were airbrushed from history by the hockey stick. One great weakness of scientific professionals is that they tend not to read too much history. Were they to do so, the hockey stick would have been laughed off the platform before it ever got endorsed by the IPCC.
One great weakness of scientific professionals is that they tend not to read too much history.
Very true, in my experience.
Reblogged this on Climate Collections.
Antarctic Sea Ice bottom falls out. Need help with this one.
1980 was lower than current
Sea ice area is rapidly gaining on the decadal minimum.
“…bottom falls out…Need help…”
It is ‘anal proplapse.’ Using vaseline…
When the sea-ice round Antarctica was above average, just a year or two ago, we were told that this was “proof positive” of global warming because it validated . Therefore, below-average sea ice must mean that global warming has been cancelled. Rejoice.
Actually, it is mere natural variation which means f-all. If people want to see signs and portents in anything and everything, they will.
“…it validated…”
the models.