Examination of Witnesses (Questions 323-333)
Professor Nebojsa Nakicenovic
8 MARCH 2005
Q323Chairman: Professor, I am sorry, the workings
of democracy do cause some inconvenience from time to time, but
I am grateful to you for coming along. I would not guarantee that
was the only division we are going to have, and so I have asked
my colleagues, including myself, to try and put our questions
as shortly as we can and if you can make your central points brief
in the answers we will get on much better. I am also told it is
important to speak up so that the record is absolutely straight.
May I start off with the first question? We have had a lot of
evidence which has criticised the IPCC emission scenarios. The
general criticism is that they are not credible, that there are
methodology problems, and I wondered whether we could just take
those criticisms in turn. The first is that the scenarios appear
to bear no relation to past trends, so that high emission scenarios
assume growth rates of the world economy that have no historical
precedent. Is that a correct point?
Professor Nakicenovic: Good afternoon. First,
I would like to thank you for the invitation to this inquiry and
for the opportunity to respond to some of these questions. As
far as the issues are concerned, and your question whether the
scenarios bear resemblance to historical rates of change and whether
they are rooted in the history, I would definitely answer in the
affirmative that they are indeed rooted in the history and I will
try to give you some examples. I think one of the main reasons
why this is important is that history teaches us quite a lot about
the rates of change, about the great transitions in the economy
and the energy system, land-use changes, all other driving forces
that are important for the emissions. I do not think that anybody
on the writing team of the IPCC Special Report on Emissions Scenarios
(SRES) believed that the history will repeat itself, but rather
that the rates of change are relevant. I think that it is also
the sense of your question. May I just spend one minute to set
the background? First, I would like to identify some of the terms
of reference that were behind the scenarios, because I think it
is important to have that up front. The SRES Report and the resulting
emissions scenarios of it was not one single event in the work
of the IPCC; but rather a part of a process. First scenarios were
published in 1990, then a second set in 1992 with a newer knowledge,
these scenarios were evaluated in 1994 and this led to the recommendations
for the development of SRES scenarios. I think what is really
important is that the SRES terms of reference specify that these
scenarios have the same range of driving forces from the demography,
through technological change, economics, land-use changes as the
scenarios in the literature and that the range of emissions should
be representative of that the literature, and in general, that
the scenarios should be representative of the knowledge. There
are about 500 scenarios in the literature, just so that you have
an impression. It is a very large set there that served as the
basis for SRES. A number of models were used to develop new scenarios,
six different models. Modelling groups were not appointed; they
volunteered to do the work. You will see later, (perhaps, in response
to some other questions that might come up) why that is important.
I would also like to mention, and with that I will conclude my
brief introduction, that the writing team included 50 authors,
many of whom were economists, but I would also like to stress,
they were not all researchers and scientists, some were also from
the private sector and from the environmental NGOs to bring in
different perspectives. Five colleagues were from the United Kingdom.
I am delighted that Professor Dennis Anderson will be giving evidence
after me, who is one of the authors from the UK, but also included
we have, for example, Dr Ged Davis, who was the head of the planning
unit at Shell at that time of SRES and now is the Director General
of the strategic insight to the Davos Economic Forum, and we had
three more colleagues from the United Kingdom[1].
This is just the background I wanted to give you. The 40 SRES
scenarios that were developed and the range of emissions are deeply
embedded in the literature and in different methodological approaches,
specifically the history, and I will try to be brief. I would
like to refer to the work of Professor Angus Maddison, who is
one of the great students of the history of economics, to his
seminal book published in 2001, on the World Economy. He calculates
the history of the economic growth, or estimates, for the last
1,000 years, but what is relevant for us here is perhaps starting
in the 1820s, or so, at the beginning of the industrial revolution.
His number for the economic development on a per capita basis
(per person) for this last 200 years is about 1.2 per cent per
year, so every year the economy grew 1.2 per cent higher. This
estimate refers to the purchasing power parity (PPP). The most
rapid period of human development economically was from the 1950s
to 1970s. At that time the world economy expanded on a per capita
basis per person at about 3 per cent per year (again in purchasing
power parity). Let me compare that with the scenarios that were
presented in the Special Report on Emission Scenarios of the IPCC.
The lowest scenarios with respect to economic growth have average
per capita PPP growth, economic growth, over the century of 1
per cent per year; the next lowest about 1.4 per cent per year—and
you can see they bracket these 200 year rates—the two highest
scenarios with respect to economic growth rates of about 2 per
cent per year and 2.5 per cent per year. They are still well below
the world experience between the 1950s and the 1970s; so I think
one can indeed argue, and lots of effort went into that, that
the future outlook in SRES is consistent with what we have seen
in the history. There is a Chapter three in the SRES report, which
is a huge book. Chapter three is 70 pages long and it goes into
great detail about the historical context of these scenarios,
not only with respect to the economics but also the demography,
technology, land use changes, and so on.
Q324Lord Elder: Sticking for the moment with
the criticisms of IPCC emission scenarios, it appears that all
emission scenarios are given equal status, and yet inevitably
some will be more credible than others. Should there not be some
attempt to see which are the most credible and perhaps to avoid
in so doing giving some sort of alarmist outcomes as possibilities?
Would it not be better for us to quantify the likelihood of the
scenarios?
Professor Nakicenovic: Thank you very much for
that question. The language that was used in the special report,
to which all of the 50 authors agreed, is that all of the 40 scenarios
are plausible. I think the plausibility is based on a number of
factors: one is, as I tried to explain before, that they are rooted
in the historical rates of change; secondly, that they are representative
of the 500 scenarios in the literature, both with respect to driving
forces from demography to economic change and with respect to
all the range of emissions. I think that is also important. Thirdly,
six different models were used, developed by six different modelling
groups, which represent different modelling approaches. There
were macro-economic models used, sometimes called top-down models,
that have much more detail about the economy and the relationship
of the economy in particular to the energy demand and how that
leads to the emissions, but there were also so-called systems-engineering
models—those are the models that would represent single
power plants, automobiles, user-devices—so they would go
from the engineering detail up and calculate the emissions. There
was this methodological pluralism that also, I think, supports
the idea of the plausibility. Perhaps another important thing
I would like to mention is that these SRES scenarios were published
in 2000 in a report by the IPCC. We have had in the meantime five
years of new literature. The new scenarios in the literature are
also consistent with SRES range. They fall within this range,
and it is not so that the SRES ranges of the driving forces or
the emissions were biased in one way or the other. To indicate
to you that the range of the emissions, which I think is a big
concern in the criticisms, is credible or at least plausible,
I do not even need to go into the area of economics. Let me just
give you a very brief example that will illustrate why the emissions
range is credible. We have today six billion people in the world
and we emit six billion tons of carbon. That means that each of
us emits one ton of carbon every single year. The highest population
projections in the literature from a number of institutions that
do global projections indicate that the highest global population
is perhaps doubling to 12 billion people[2].
That is the highest (if we use the language of your question),
credible population projection (but 15 is also imaginable) so
that 12 billion people would already double our emissions to about
12 billion tons of carbon. If the whole world in 100 years from
now would have the same emissions as we have on average in the
wealthy countries, in the OECD countries (that include Western
Europe, North America) of averages about three tons per person
on average per year. that gives you 36 billion tons worldwide.
That is about the upper SRES range. That is about the range I
have given you. That results even though there is also efficiency
improvement in the higher scenarios. The lower part of the range
constructs similarly. The lowest population projections are—and
this might be a little bit surprising—as little as four
billion people, a substantial decline from today. That would be
a much more elderly population, in particular in the northern
regions of the world with most affluent societies. If they would
be also only emitting one ton of carbon on average, that would
be four billion tons, and the lowest SRES scenarios are in that
range. One can assume much higher efficiency of the energy system,
introduction of carbon-free energy sources, and one could cut
that down to about two or so (tons of carbon per capita per year),
and there are scenarios in the literature that have climate policies
that reduce emissions far down. In the SRES scenarios climate
policies were not allowed by the terms of reference—in mitigation
scenarios we find climate policies—so no additional post-Kyoto
agreements or anything of that sort was assumed in SRES. I think
that if one looks at my very, very simple calculation, the SRES
range is plausible, even without going into the economics and
other factors, simply because energy is essential for human activities,
and currently energy is fossil-based so even transitions away
from fossil would still lead to some of the emissions over the
next century.
Q325Lord Vallance of Tummel: Professor, may
I bring you back to the economics for a moment, because I suppose
the third main criticism of the scenarios is that they use market
exchange rates rather than PPP in their projections. We know that
you responded to Henderson-Castles' critique on this, but we would
welcome an update on what the current state of play is, because
I noticed in your answers to one of the earlier questions that
you were talking in PPP terms. Does that mean that you now acknowledge
that PPP is the right way of approaching this, and, if you do,
what difference might that make to the emissions forecasts?
Professor Nakicenovic: First, I would like to
state that the scenarios as published in 2000 were formulated
both in PPP and in market exchange terms, so it is counter-factual
to say that PPP was ignored. I think it is important that I stress
that. I also want to explain to you how PPP is accounted, and,
indeed, I am still puzzled why this is continuously being ignored.
SRES report has an appendix of 200 pages (from pages 380 to 580)
where every single scenario is precisely documented, and I will
be happy to leave a copy here as evidence. Six models, as I mentioned,
were used, according to intergraded assessment models, to develop
the scenarios. One of those models, the model we have developed
at IIASA, where I work, is calibrated in PPP and, since all of
the models developed all of the four scenario families, we have
PPP trajectories for all of the 40 scenarios, and this is why
it was possible for me to compare the future PPP growth rates
in the scenarios with those that Professor Angus Maddison published
two years later after SRES report was published. I think it is
really essential that I point this out, that there is a PPP calibration
in SRES. At the same time, I think I also need to state that most
of the literature—I mentioned that there are about 500 scenarios
in the literature-at the time of the writing of the report (there
are in the order of 600 scenarios now)—is still in market
exchange rates. Perhaps this will change in the future. But it
has stayed in market exchange rates for a long time. The reason
why we developed a model in PPP is that during the 1990s I chaired
a joint study of IIASA and the World Energy Council (WEC) that
is situated here in London. It is the largest energy association
in the world and they regularly do scenarios. Our group developed
a set of scenarios, the IIASA-WEC scenarios that were published
in 1998 by Cambridge University Press in a book called Global
Energy Perspectives. One of the requirements of that study was
to look—
Q326Chairman: We are going to have to vote in
a minute, so can you pause when you get to a good point?
Professor Nakicenovic: I can pause in 30 seconds,
if that is okay. I just wanted to complete this thought. One of
the objectives was to look at why two billion people do not have
access to electricity. This is a huge challenge today, partially
because there is no infrastructure but partially because they
cannot afford energy, and PPPs that I have measured to look at
it, because people buy energy usually at different prices than
the International Exchange Rate prices in many of the developing
countries. So that was the reason why we developed it, for cross
country comparison.
Chairman: I am afraid we have to go and
vote. We will be back as soon as we can.
The Committee suspended from 4.12 pm to
4.20 pm for a Division in the House
Q327Lord Vallance of Tummel: Could you come
to the second part of the question: how sensitive are the emission
forecasts to the choice between MER and PPP?
Professor Nakicenovic: If you will permit me,
I wanted to add a few more points to the first part of your question,
and then I will come to the second. I also wanted to mention that
Mr Castles and Professor Henderson actually cited IIASA joint
study with the World Energy Council as an example of how they
feel these things (eg PPP calibration) should be done, but that
is an example of a counter-critique on the IPCC scenarios because
the same methodology was used in SRES. I would like to also mention
that to my knowledge IIASA-WEC study was the first attempt to
do a 100 year scenario using PPP. In the meantime there are a
number of other studies, and let me just mention some of them
for completeness so that you know that there is work going on.
There is the model of Dr Chris Hope, the PAGE model, that is calibrated
in PPP as far as I know, then there is the Global Scenario Group
that has developed PPP scenarios with a simulation framework,
then Dr Rich Richels and Professor Alan Manne from Stanford who
have calibrated MEGRE model also with PPP, and then the World
Energy Outlook that is published in regular periods by the International
Energy Agency—the last one was 2004—is also calibrated
in PPP, but this is a shorter term study. World Energy Outlook
was for 2030, then there is the European Union's work on the World
Energy Technology and Climate Report, the scenarios that were
developed by Dr Patrick Criqui, (with POLES model) from France—that
is also calibrated in PPP to 2030—and most recently (I think
that is particularly interesting) Professor Angus Maddison has
also produced a PPP scenario to 2015. All of these new scenarios
have an economic growth rate on a per capita basis in the order
of about 2.2 per cent per year[3],
and that is in the upper range of SRES. I just wanted to point
that out as well. Before I come to the second question, let me
also say that great progress has been done in the PPP data in
particular with the International Comparisons Projects, so the
data is quite available on the expenditure side, but one of the
big issues is that we often deal with trade. In particular in
this kind of long-term scenarios, it is not only trade in oil
and other commodities, in the future there might be also trade
in pollution, in carbon, for example. That occurs at a market
exchange rate; and not in PPP terms. There are also some other
reasons, depending on the question, for why most scenarios stay
with the MER (the market exchange rate) calibration. I think there
is no universal approach to that (and expect that both PPP and
MER will continue to be used in parallel). Another barrier to
using PPP more widely is that the data are very sparse still.
My personal impression is that they are about 100 times more sparse
than the market exchange rate data. In particular, they are mostly
expenditure oriented, there is very little information about the
input, output relationships that we need in many of the models—for
example, production accounting, and so on. The last thing I want
to mention is that the engineering models of the types that we
use (at IIASA), model individual facilities, they use prices to
do that, and when we achieve cost minimum in the model, according
to the theory, that is called the duality theory, that is supposed
to emulate an location of very scarce resources by competitive
markets. In other words the model is supposed to behave in the
same way as the market would allocate scarce resources. If we
would do that in PPP we would get the wrong answer; so here one
has to use market exchange rates. There are also attempts to use
hybrid approaches, but (what I would like to communicate to you)
in particular is that most of the literature continues to be in
MER. For whatever reason, that is the reality. Less than one per
cent of all the scenarios are in the market exchange rate. The
second question: what difference does it make whether you use
PPP or MER? Let me try to illustrate that with the following argument.
Let us take up a hypothetical situation of China, but we could
take India or any other developing country. If we measure the
Chinese economic output in market exchange rates, it would be
four times lower than in purchasing power, roughly four times
higher, but the factual situation on the ground is that the emissions
are what they are. China is emitting about half a ton of carbon
per person whether you measure Chinese affluence and standard
in PPP or market exchange rates. There are compensating mechanisms
in one shifting from one to another—in measuring economic
activities in purchasing power parity results in lower energy
intensity and carbon intensity and lower all of the other physical
intensities of the economy. China in PPP has about four times
higher GDP than in market exchange rates, but it also has about
four times lower carbon energy intensity, so the emissions at
the end of the day are the same; and in history that is, of course,
the same. If you use Angus Maddison's PPP data for history or
whether you use market exchange rate data for GDP and we look
back in time, emissions factually do not change because they have
been estimated from physical quantities, like how much coal was
used, how much oil was used, and in principle the same thing should
hold for the models and for the future scenarios, and in our case
(IIASA scenarios) it does, and in our model of calibration it
does so because of the off-setting mechanisms. So, when we evaluate
one country in PPP terms and its possible development trajectory
for the future, the energy intensities of that country are lower
than if they would have been estimated in the terms of market
exchange rates and carbon intensities are lower, so those two
things offset each other so that the emissions are in principle
the same[4].
In practice the models are complicated, so I use the words "in
principle". In practice it is very complicated and one cannot
turn all of the knobs and whistles always ideally, so there might
be some discrepancy. In fact, maybe you have had evidence to that
account in this Committee. For example, Dr Rich Richels and Professor
Alan Manne in their PPP calibration of their model MERGE come
up with 18 per cent difference. What other groups will come up
with if they do PPP, I cannot judge. In our case we have really
gone to a great effort to account for all of these compensating
mechanisms and we do not see any noticeable difference, but I
know that colleagues like Professor Richard Tol says that in his
model it makes a great difference. I do not know whether he will
change his mind if he looks at some of the, let me call it, behavioural
equations (eg energy and carbon intensities), but it is important
to say that an energy intensity measured in PPP of developing
countries is very similar to the energy intensity of this (ie
developed) country. If you measure it in market exchange rates
it is four times higher and it looks more like our energy intensity
perhaps 100 years ago. So I would argue very strongly that in
principle it should make no difference on the future emissions
trajectories. If it does make a difference, then that is because
of the lack of data, lack of time to recalibrate the model. From
my point of view doing a model in PPP instead of doing it in market
exchange rates is almost the same amount of work as developing
a new model. In any case, it is the same amount of work as developing
a new base year for the model; so it is a huge effort.
Q328Lord Lawson of Blaby: I would like to follow
on with that, if I may, first, but shall try and be brief because
we are very pressed for time because of the divisions that have
been taking place on an important issue today. You quoted Angus
Maddison as a great authority, and that is absolutely right—he
is on growth rates. He has given us written evidence in which
he has said, among other things, "An explanation of the importance
of using PPP converters rather than exchange rates in comparing
levels of performance between countries and in establishing measures
of aggregate world output, with an illustration of the implausibility
of using exchange rate converters in historical analysis of futurology
as in the IPCC's Special Report on Emissions Scenarios."
That is his view, that your scenarios are implausible, and he
is the authority that you prayed in aid. You say that you have
produced a PPP series. Are you aware that Mr Ian Castles, a very
distinguished Australian statistician, again has submitted written
evidence to us saying that the so-called PPP-based figures in
the MESSAGE scenarios are not genuine measures of GDP? Also, are
you aware that you have quoted in your preliminary remarks measures
of population which go far in excess of anything that the United
Nations or anybody else has put as likely population growth and
population projections for 2050, which is not all that far away
in population terms? We have a pretty good idea of what the population
is going to be then, and yet yours go way above that. You also
assume, in addition, that you get these high figures by saying
that it is in the upper end of the range, that global per capita
carbon dioxide emissions will increase significantly, whereas,
in fact, global per capita carbon dioxide emissions have remained
totally almost absolutely constant for the past 25 to 30 years,
and that is an established fact. So it does seem that your scenarios
are doubtful, and yet you seem to be content simply to defend
everything you have done, to take no notice of informed criticisms
that have been made. Are you aware, finally, that Professor McKitrick,
a Canadian economist specialising in this area, has given evidence
to us in which he says inter alia that one of the striking
differences between the second assessment report of 1995 and the
third assessment report of 2001 is the loss of participation of
mainstream economists in the latter, and he gives details of that.
He concludes, "Of even more concern to me is that even after
serious flaws in the SRES have come to light, the IPCC has chosen
to use the same scenarios for the fourth assessment report even
though it is not due out until 2007." Would it not be better,
instead of trying to defend the intellectual capital which you
feel that the IPCC has built up, if you were to respond properly
to the intelligent and informed critiques that have been made
and produce something which is closer to the probable truth?
Professor Nakicenovic: With respect, I beg to
disagree on a number of points that you have raised. In particular
the first two. I have not seen Professor Maddison's submission
to this Committee, but I am not surprised that he says that PPP
should be used because he uses PPP in his work; and I am of course
aware of Mr Castles' critique on a number of occasions, but as
I have tried to say in response to the other questions, SRES report
does also use PPP and it would be good to at least hear whether
the experts are contesting the fact that the report uses PPP or
whether they feel it should have been done better. Simply to say
that this is not PPP is not good enough as far as I am concerned.
It is important to know what the development prospects should
be and how the PPP trajectory should look. It is easy to talk
hypothetically, but Professor Maddison's scenario goes to 2015.
We would have to see longer-term PPP scenarios developed by this
gentleman and other experts that go to 2100, and, of course, I
would be very happy to include that into my own assessment and
compare it to our results, but for the time being we are discussing
most of those things hypothetically. There are many questions.
I will try to take one at a time. The comment on the population
growth and that it is not credible, I would unfortunately also
have to reject that. The scenarios reported in this (SRES) book
as the scenarios were done with knowledge about the future population
roughly state of the art of the year 1996, and I do have to say
a few things just by way of introduction. In the early 1990s it
was felt that the most likely or medium population projection
for the world was about 12 billion people, the top range perhaps
18 or so. By the time we were writing this (SRES) report the medium
was 10 billion people. The highest range about 15, the lowest
about six billion people. I am talking about the year 2100, 100
years from now. The two main organisations that do population
projections for the world is IIASA that I am affiliated with—it
is a very strong demographic group that publishes global population
projections at regular intervals—plus, what was mentioned,
the United Nations. Those scenarios are done very, very seriously
and also reviewed with many, many groups and, as it happens, the
two projections do tend to coincide. Ever since this (SRES) report
has been published the population projections have been revised,
and that is perhaps the biggest change in the literature since
the publication of this report; and so that you have a feeling
for the order of magnitude of the exchange, the medium projection
is now no longer 10 billion people but about eight billion people;
the higher is now in the range of about 12 and the lower is in
the range of about four instead of six. One way to imagine it
is that the global population 100 years from now is moving by
two billion people down. That can be good news, of course, but
it can also be bad news. The bad news is that the population is
ageing and we will probably have to invest quite a lot in many
of the support systems for the elderly population, but that in
many of the developing countries that have a rampant and explosive
population growth the population is going to be likely lower.
I would like to pose the following argument just to conclude on
the population issue (and this is a fact underlying the scenario
literature behind this report and the new literature), that higher
the rates of economic growth usually are associated with lower
population—I think that is good news—but also with
lower rates of emissions growth. It is not necessarily true that
high economic growth rates lead to the highest range of emissions.
High economic growth rates, because there is lots of capital investment,
lots of research and development, lots of education and capacity
building, usually mean that the newest technologies are applied,
and usually the newest technologies are not only the saving of
the input of energy but they are also emission saving; so high
growth scenarios do tend to have, everything else being equal,
lower emissions than the low growth scenarios. I think that is
also important to keep in mind. Then it was stated that per capita
emissions had not increased in the world. That is simply not correct.
Per capita emissions have unfortunately increased over the last
200 years and continue to increase. In the long term the average
per capita emissions increase is about point 5 per cent to about
point 7 per cent per year. Every year emissions increase because
the population is increasing a little bit over 1 per cent. We
have 1.7 per cent increase in total emissions.
Q329Lord Lawson of Blaby: Are we talking about
emissions per capita?
Professor Nakicenovic: If you divide it by population,
they are still increasing on average, in particular in the developing
countries. It is true that in some of the most industrialised
countries the increase has been relatively low over the last two
decades, but in the developing countries it is still increasing.
If you take a country like China, there is an increase, they have
revised recently their coal statistics, so emissions are indeed
increasing around the world. I hope that I have addressed most
of the points. I think there was one: why the four scenarios are
used if there was such strong evidence that the scenarios should
be revised. As far as I know, IPPC or its fourth assessment report
is going to not develop new scenarios—that is simply not
possible from my point of view[5]—but
it is going to review all of the new literature. I have tried
to give a glimpse to this Committee of my own analysis of how
the literature looks. There is some revision on the population,
there is very little revision, if any, on the economic growth
rates across the range, on the technology it is very similar,
and certainly the range of the emissions is still valid as published
in this (SRES) report vis-a"-vis the new literature.
I just want to stress that, because we put quite a lot of effort
into looking at most of the new sources.
Q330Lord Layard: I want to come back to the
issue that was raised just now of whether the special report receives
little exposure to mainstream economists and national accountants.
Is this a fair impression and do you yourself have views as to
how the scenario might be improved?
Professor Nakicenovic: Many of the colleagues
who participated in writing this report and in particular in modelling
are economists, I would say roughly about a third are of the economic
profession. I am trained as an economist and I am Professor of
Energy and Economics. There were a number of colleagues also who
are very, very close to national accountants that have been associated
with the (SRES) exercise. I think it is probably unfair to say
that it was completely decoupled from the mainstream, whatever
that might mean, economic profession. In particular, the larger
energy modelling community and the economic modelling community
in general has a number of networks in which scenarios are compared
all the time, for example the Energy Modelling Forum at Stanford
University with which the authors of this (SRES) team had very
strong collaboration and many of those were actually lead authors
and who are themselves economists. Let me also mention Dr Knut
Alfsen, who is the Director of Research at the Statistics, Norway.
He was appointed as the lead author of this (SRES) report, and,
as far as I know, is the lead author of the Fourth Assessment
Report as well and, I believe, was also cited in this Committee
as the Norwegian who did a very good study on the GDP. That is
Dr Knut Alfsen. The other person from the Statistics community
who was involved was Dr Ton Maders from the Central Planning Bureau
in the Netherlands Bureau of Economic Policy Analysis. He was
also involved in the IPCC scenario exercise. Let me also briefly
mention that, after the initial discussions with Mr Castles and
Professor Henderson that took place in Amsterdam two years ago,
we had attained an agreement to organise a scientific meeting
to deal specifically with this (PPP issue), and to invite people
who have been doing PPP, but then there have been lots of polemics
and public discussion and some of us decided to go along with
that idea; and so we did have a meeting in Stanford exactly a
year ago that included, for example, Professor Alan Heston, who
is one of the key people in the PPP area, and many other colleagues.
I understand there was a meeting at OECD later last year, in which
I did not participate, so I cannot report on it, and I believe
it was mentioned also in the proceedings of this Committee that
in January there was a meeting that was organised by IPCC that
spent a considerable amount of time on the issues of how to deal
with PPP, how to calibrate models in PPP, and also spent lots
of time discussing what is new in the literature and how representative
these (SRES) scenarios are to what extent are they up to date
five years later.
Q331Lord Skidelsky: We were able to show that
the global per capita CO2 emissions level is a stationary constant,
neither drifting nor turning upwards, and the trend has not changed
for several decades and, indeed, is trending slightly downwards
since the early 1980s. That is Professor McKitrick. Is he wrong?
It is directly contradictory to what you said. Is he just wrong?
You are asserting he is wrong?
Professor Nakicenovic: Yes, at the world level
he is wrong, not necessarily in every single country[6].
Q332Lord Skidelsky: He is talking the world
over?
Professor Nakicenovic: The world over.
Q333Chairman: That is a good question and a
clear answer, if I may say so. Can I say to you, first of all,
I am sorry that we interrupted you, but you managed extremely
well to keep coherent and clear and we are very grateful to you
for coming to us, for giving us your very clear views on the issues
that we are concerned with. It has been a great help to the Committee.
I am very grateful to you. Thank you very much.
1 Mr Doug Mckay, Shell; Dr Laurie Michaelis, Environment
Change Institute, Oxford; and Dr Ken Gregory, Centre for Business
and the Environment. Back
2
Global population projections are regularly published by the
United Nations (UN) and the International Instituted for Applied
Systems Analysis (IIASA). SRES scenarios were based on the range
of these population projections as published by 1996 ( when the
work on SRES commenced). In the meantime, these projections have
been updated by the UN and IIASA. Back
3
Maddison's contribution to the 2002 OECD publication "Development
is Back" gives global GPD per capita growth rate of 2.1 per
cent per year between 2001 and 2015; the International Energy
Agency in its 2004 World Energy Outlook gives global (PPP) GDP
per capita growth rate of 2.2 per cent per year between 2002 and
2030; and European Commission 2003 report World Energy, Technology
and Climate Policy Outlook gives (PPP) GDP per capita growth rates
of 2.3 per cent per year between 2000 and 2010, 2.1 per cent per
year between 2010 and 2020 and 1.8 per cent per year between 2020
and 2030. Back
4
Higher GDP in terms of PPP is associated with lower emissions
intensity of GDP. The two factors cancel out resulting in the
same future emissions Back
5
Because the process takes a lot of time and requires a large
effort. It would indeed be possible to develop a new set of scenarios
for the next assessment report. There are many new scenarios in
the literature since the publication of SRES and these are being
reviewed and assessed. Back
6
Global energy-related carbon dioxide emissions have increased
at about 1.7 per cent per year during the last 30 years while
population increased 1.6 per cent per year (IEA World Energy Outlook
2004 or BP 2004 Statistical Review of World Energy). At face value
this might imply that per capita increase was very low or stationary.
However, per capita emissions are rapidly increasing in developing
countries, so that temporary per capita decreases in the "North"
during the late 1970s and 1980s no longer offset this pervasive
development. In fact, global carbon dioxide emissions have increased
at 3.1 per cent per year during the last three years (2000 to
2003), while population increased at 1.2 per cent per year, leading
to per capita emissions increase of about 1.9 per cent per year,
well above the average historical experience of the last 200 years
of 1.7 per cent per year. Back
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