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Climate anomalies and world ice cover -

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Climate anomalies and world ice cover

Richard Peltier was a lead author on the IPCC 4th Assessment Report Chapter 6. This describes what
past climates can reveal about the quality of models that predict future change. He has concluded
that climate models are actually quite accurate. He says the climate anomalies quoted, such as the
Medieval warm period, and the little ice age, were not global, but experienced locally. Richard
Peltier analyses satellite data of world ice cover and sees a clear massive and increasing rate of
ice loss on Greenland and west Antarctica.


Robyn Williams: Up the coast from San Diego is the Scripps Institution of Oceanography where CO2
was first tracked over 50 years ago, and much further north and east is Professor Dick Peltier, one
of the authors of IPCC and expert on the fate of glaciers in these warming times. His models delve
back into the past, and he thinks they're working very well indeed.

Richard Peltier: Well, the conclusion of this work was that the investigation of the ability of
models that are used to make global warming projects to actually reconcile what we know has
happened in the past is a superb way of actually testing their fidelity.

Robyn Williams: How far back do you go? How far back does your own work go, for that matter?

Richard Peltier: My own work goes back as far as 600, 700 million years into the past, but I'm best
known for my work on glacial climates. That is, climates of the Earth going back maybe a few
hundred thousand years, and most strongly actually with the time in the past when the northern
hemisphere continents were last covered by a maximum extent of land ice, which is about 20,000,
21,000 years ago.

Robyn Williams: How extensive was that ice?

Richard Peltier: The ice was extremely extensive at that time. The North American continent,
particularly Canada, was covered by an ice sheet about four kilometres thick, north-western Europe
was heavily glaciated, sea level had fallen by on average about 120 metres. So this was the last
maximum of what we call the late quaternary glacial age.

Robyn Williams: So where we're sitting now in Toronto at your university, we could be looking up
and seeing four kilometres of ice above us.

Richard Peltier: We would have been squashed of 2.5 kilometres of ice thickness at this point.

Robyn Williams: That's enough!

Richard Peltier: Quite enough.

Robyn Williams: Looking at that kind of story, are you also examining some of the examples that
have troubled people who are uneasy about the standard interpretation, like what happened in the
Middle Ages, the warming, the mini ice ages and all that? Are you able to fit those supposed
anomalies into your picture?

Richard Peltier: This is absolutely possible, and one of the sets of calculations we're doing now
is actually a set of millennial timescale simulations using the modern coupled atmosphere ocean
climate models to see to what extent we are able to simulate, for example, the Medieval warm period
and a little ice age, et cetera. But one of the things which is already clear on the basis of the
data is that these instances of warm or cold climate seem not to have had global incidence, they
seem more to have been region characteristics, for example, of Europe or elsewhere.

Robyn Williams: So there was something going on in Europe locally, whereas globally in the Middle
Ages, for that example, there was a different story altogether.

Richard Peltier: Yes, not at all clear. It looks as though the so-called Medieval warm period was
not uniformly warm over the entire surface of the Earth.

Robyn Williams: So it's not an anomaly as it's brought out to be on many occasions by people who
are sceptical about the standard IPCC story.

Richard Peltier: Yes, not necessarily a global anomaly at all but rather one of regional incidence.

Robyn Williams: So how come it works as an argument in public?

Richard Peltier: That's a very interesting question. What I've just said is that the idea of the
Medieval warm period is one that has to be approached with a certain degree of nuance. If it is in
fact true that that warming was only of regional incidence, then the issue as to whether a global
model should be able to reproduce it is really not on.

Robyn Williams: You say you'd handled glaciers, so what was your reaction when there was this
embarrassment about the IPCC version of glaciers in the Himalayas being gone, if you like, by 2035?

Richard Peltier: I think that that's generally accepted to have been an error in the second volume
of the IPCC report. How it got in there is still a little bit unclear but it certainly did not come
from peer-reviewed scientific literature. And I think when you're looking at documents which are
1,000 or more pages long and which involve the interactions of literally hundreds of scientists, it
would be very surprising if there were not flaws of this kind found. However, the more interesting
thing of course is what's happening to land ice worldwide at present.

One of the things which I'm working on actively myself is the interpretation of data that's coming
from the so-called GRACE satellites which are measuring the time dependent gravitational field of
the planet, over Greenland, for example, over Antarctica, over Alaska. And it's very clear on the
basis of the GRACE satellite observations that there is a massive rate of mass loss from the ice
over on Greenland, from the collection of small ice sheets and glaciers which exist over the high
topography in the Canadian Yukon territory and over the American state of Alaska, as well as over
west Antarctica where the rate of mass loss is exceptionally high.

So, rather than focusing on little patches of real estate where there may be issues as to whether
the ice caps are growing or decaying, of much, much greater concern is the fact that these massive
polar ice sheets are not only losing mass but losing mass at an accelerating rate according to the
GRACE satellite observations. This is work on which I have been very active myself and which I
understand something of, and this issue is really one which I think deserves a great deal of
attention by the scientific community and by people in general.

Robyn Williams: Is this recent material?

Richard Peltier: Yes, this is recent material. My own papers on this have come out only in the past
year. The GRACE satellites themselves were launched only in 2002, so they've been up for only eight
years. There have been many more scientists than simply my own group here in Toronto working on
these data, and they're providing extraordinary insights onto the impact of the global warming
process on those polar accumulations of land ice which should be the most susceptible to the global
warming process, and what we're seeing happening at high latitudes is exactly what we expect to be

Robyn Williams: At the same rate or faster?

Richard Peltier: On Greenland, for example, it's very clear that the rate of mass loss has been
accelerating, and of course the rate of loss of sea ice in the Arctic Ocean has experienced very
significant degrees of melt-back at the time of minimum ice extent, around October, over the past
couple of decades, several decades since the satellite observations first became available
beginning in 1979. So wherever we look at the poles, especially in the northern hemisphere where
there is what we call a polar amplification of the global warming taking place, what we see to be
happening in these icy parts of the Earth's system is exactly what we expect to be happening as a
consequence of the global warming process.

Robyn Williams: And presumably there are other indicators as well apart from that satellite?

Richard Peltier: Absolutely. Other satellite observations such as the passive microwave
observations that are being made of arctic sea ice extent, observations on the cryosphere on land
of the disintegration of permafrost at high latitude which is causing havoc with the building
industry here in Canada...

Robyn Williams: In what way is it causing havoc?

Richard Peltier: When the active layer begins to melt to greater depths, structures that have been
constructed on the active layer begin to slump sideways, buildings basically fall apart, and you
can see this actually in forests at high northern latitudes now; trees tilted at extremely odd
angles because their footing, if you like, in the permafrost is no longer solid.

Robyn Williams: Given that sort of evidence, how do you view the current political debate where the
scientists seem to be up against it in terms of their overall statement on the seriousness of
global warming?

Richard Peltier: What surprises me most about this debate is that people are taking seriously at
all the arguments against the validity of science which have been collected over this long series
of IPCC reports that span now going on 20 years or more. It's extremely surprising to me that the
political right is achieving so much damage in the discourse between scientists and the public. I
understand that this is associated with the fact that the science suggests that we really are
forced to change our lifestyles, in a way, to change our energy systems, to switch away from a
fossil fuel based energy economy, and we all understand that this will require very significant
adjustments in our lifestyles. But I think we really need to get on with it, and what surprises me
is that the public is being so misled by the political right that it's liable to make decisions
which are in its own worst interests.

Robyn Williams: Is that the case in Canada as well as in Australia and Britain?

Richard Peltier: Yes. I mean, the circumstance here in Canada is exactly the same. In Canada of
course we have, superimposed upon this general anti-dialogue between the right and the scientific
community, is the complexity that's caused by the issue in Canada here over the oil sands in the
province of Alberta, which happens to be the home base of the right-wing political party which is
currently in government.

Robyn Williams: Yes, in fact those oil sands, enormously rich in oil, but would be a huge challenge
to extract and very, very costly, and so making a decision about whether to exploit them is very
much a political one, isn't it.

Richard Peltier: The oil sands issue in Canada is enormous. I've visited Fort McMurray, I've flown
over the sites in helicopters and float planes and it really does look like and is a lunar
landscape in many respects. But really the tragedy of the Canadian effort to develop the oil sands
is that it's been allowed to proceed at such a pell-mell rate that the province of Alberta, its
economy has been topsy-turvy at the rate at which it's decided to allow development to proceed.

An interesting contrast is between the province of Alberta and the country of Norway. Of course
Norway has enormous North Sea oil wealth and it is and has become over the last several decades an
extremely wealthy country, but the Norwegians put almost 100% of their yearly earnings in oil into
an equivalent heritage fund for the Norwegian population. In Alberta, the so-called Alberta
heritage funds are verging on bankrupt, it has nothing in terms of resource put aside for the
people of that province. What needs to happen in Canada is that the pace of growth in the oil sands
has to be slowed down to allow technology to catch up to it so that if the resource is exploited it
can be done so in a way which doesn't lead to massive increase in the rate of greenhouse gas

Robyn Williams: Given the kind of booting that the IPCC has had in the last few months, do you
think the scientists and those involved with the process need to do something that opens up what
they do or changes made in some way so that the public can look at this complicated process and
have more confidence in it?

Richard Peltier: That point is very well taken. I'm of the opinion that the debate over this issue
of global warming is so important that scientists need to go all the way into making full
disclosure of all of the data which are used to produce all of the reports that are written on this
subject. It's not that the IPCC has been loath to release the information on the basis of which its
reports are written, but the raw data, the datasets which we employ to come to the conclusions
which we come to, these should be made available for all to investigate if they choose to do so.

So I think the IPCC could gain a great deal by going even further than it has already gone by way
of openness and becoming engaged in direct dialogue with the public. Many of us who are involved in
this science are already going into church basements and talking to the public on these issues, and
certainly one of the things that I found is that people by and large are not happy to receive the
information they receive through newspapers and so on, they actually want to find the information
directly from the mouth of scientists. So I think all of us need to do a lot more of this to talk
to the people in our communities about what we have come to believe and to discuss with them why we
believe what we believe and to go through the arguments as carefully as we possibly can.

Robyn Williams: Richard Peltier, who is professor of physics at the University of Toronto, and the
lead author of chapter 6 of IPCC. And you too can take part in a dialogue on items from this
program by going to The Science Show website.