Examination of Witnesses (Questions 100
- 115)
WEDNESDAY 13 DECEMBER 2000
PROFESSOR DAVID
QUENTIN BOWEN,
PROFESSOR ALAN
O'NEILL AND
DR SIMON
SHACKLEY
100. The Hague conference was very much about
carbon sinks and their role. Do you think that in European research,
our contribution to the IPCC, we have tended not to have researched
enough into that area or given it sufficient recognition?
(Professor O'Neill) I would tend to agree with you.
It is an area that we are recognising is important. There are
important feedbacks that need to be brought into these climate
models. The fact is that science evolves. It is not an oversight.
We are starting to appreciate more and more the potential for
these feedbacks and the importance of representing them. If you
go back, say, ten years, it is only in the last decade or so that
we have attempted to represent properly the role of oceans in
these climate models. That is absolutely fundamental. We have
to realise that we are involved in a very rapidly evolving and
developing science.
101. 20 or 30 years ago, of the coal, oil gas
and all fossil fuels that have been used in the last century or
whatever, the rise in carbon dioxide concentrations in the atmosphere
would be much greater were it not for the amount already absorbed
by the world's forests and oceans. It would be twice the rise
that it has been. That is the case, is it?
(Professor O'Neill) I do not know if it is a factor
of two exactly but certainly there would have been much more carbon
dioxide in the atmosphere it had not been for the natural absorption.
102. In that Hague compromise, do you have a
feeling overnight, and since then, that there is a compromise
there and what is the shape of that?
(Professor O'Neill) It is difficult because this is
very much an area of considerable uncertainty. If we are talking
about the role of, say, vegetation and planting forests as a way
of absorbing the excess carbon dioxide that we are emitting, that
could be slightly dangerous in the longer term because the existence
of climate change could end up with vegetation which currently
acts as a carbon dioxide sink under present conditions and could
then become a source rather precipitously.
103. How?
(Professor O'Neill) For example, if we have changes
in climate zones and vegetation dies away—it is not able
to rapidly respond to a change of climate—or the type of
vegetation that exists is a less strong carbon sink, the end result
of that is that more carbon dioxide is released into the atmosphere.
104. The higher is the per cent of tree cover
of the land mass, the greater the concentration of carbon dioxide.
(Professor O'Neill) If everything else is static.
The problem also is that in between putting large bands of forest
changes the reflectivity of the earth and the forests tend to
be darker and they tend to absorb more solar radiation. When we
are talking about the land surface by vegetation feedback in the
climate, this is precisely the area that we do not know anything
like enough about.
105. Dr Shackley, as a social scientist, are
social sciences adequately reflected in the work of the Hadley
Centre?
(Dr Shackley) No. They do not do any social science
work. They rely on other social scientists, for example, to provide
them with scenarios of future greenhouse gas emissions from different
regions of the world, making different assumptions about economic
growth rates or population change. They use other people's social
science. Their mission is not within social science. Within the
new Tyndall Centre that I am part of, part of the mission of that
is to integrate social science much more effectively into the
existing natural science. We will be working with the Hadley Centre
to aim to do that.
Dr Gibson
106. You have indicated there is not a lot of
coherence; there are a lot of things missing and people doing
different things in the way that academics do for the great fives
and five stars and so on and this is full of five stars all doing
their own thing, competing against each other. Do you think there
would be a major advance if we worked together? People are getting
a bit fed up with you crying wolf about global warming. It can
be said too many times. Would a coherent science policy reflect
any way of getting the message over much more substantially in
a social context but also in the academic arena of scientific
research as well? I am aware of the stuff coming from Norwich
about to heck with it all; just let the coastline disappear. Why
bother? It is too much money. Just do not let people build their
houses too close to it. Build them in Norwich, not on the coast.
People are getting rather fed up. It has been going on a long
time. How can we get the arguments that you are portraying, and
obviously care about, over in a coherent way in terms of selecting
a science? You have said there are some gaps. What can we do to
bring it all together in terms of a really big scientific message
that looks coherent and not just groups competing with each other?
(Professor Bowen) It is an extremely tall order. Had
it been readily possible, I suspect it would have been done by
now. Turning again to the States, people there are not anything
like as bothered about global warming as they are in this country.
I cannot tell you what the reasons might be, but they are more
relaxed about things. Maybe there is something in that system
that can help us, but yes, as one talks to ordinary people these
days, people are getting fed up with it and they seem to sense
that something is wrong. It is the same story and there is no
great step forward to elaborate it.
107. Let us hear the social scientist tell us
what is wrong.
(Dr Shackley) I am not sure I agree that there is
anything wrong in having different messages and having some diversity
because I think that encourages debate. It is useful to have those
inputs. There is a danger if we try and coordinate things too
much and try to create a single message. What if the message is
the wrong one? Can we be sure that it is the right message? I
think you will find there is disagreement about what the message
should be.
108. What is the message you have for us?
(Dr Shackley) My message would be that climate changes
the global scale. There is a surprisingly high level of confidence
amongst the scientific community that climate change will occur
on a global scale. When you go down to other scales like the regional
scale and the national scale, the science is simply much more
uncertain so it is much more difficult to start to attribute particular
extreme events to the general climate change. Nevertheless, over
the time periods we are talking about, it is likely that climate
change will begin to influence climate at these local levels.
We might as well act in ways that have benefits in terms of preparing
ourselves for climate change but also have other benefits for
other reasons. You mention the coastline. It is not just because
of climate change that people—including noticeably the Environment
Agency—are very keen on managed realignment. There are many
other benefits around managed realignment. I think we have to
be looking at responses that combine a number of different policy
objectives and not just rely on climate change as the sole justification
unless we have very good scientific evidence.
109. Can you think of one piece of scientific
evidence that would do it? That is a terrible thing for scientists
to ever answer but is there one thing, in your wildest moments,
if it was proven, that would do it and convince governments to
sit up and take notice across the world. We are not convinced
that floods are due to all that really. What would really make
a difference? Is it just too long term and too imprecise?
(Professor O'Neill) The fact that you are not convinced
about the recent floods and global warming is absolutely fine
because neither am I. You could not possibly say that that is
the case. What we would be looking to see is that in the longer
run of things there would be increased frequency of these kinds
of events. It is very hard to pick on one single thing. What we
are getting is from different sorts of quarters, different pieces
of evidence fitting together into the big jig-saw puzzle. I do
not see any missing corner piece that would absolutely clinch
it. It is not likely that the west Antarctic ice sheet is going
to fall off its ledge and drop into the ocean. I do not think
there are things like that. It is mounting, cumulative evidence.
Two things strike me in terms of public perception. One is the
longer term in which it takes for the real signal of this global
warming to emerge from the natural variability. Secondly, it is
because perhaps wrongly people have been conditioned to the notion
that scientists can talk about systems with a degree of certainty.
It may be with some control systems we can do that. When we talk
about the natural system, there is uncertainty inherent in that.
It is not just about the fact that we do not know enough about
the equations or we cannot stick them in the computer well enough.
We are dealing with complex systems and frankly, when I went to
university, I was not trained to deal with these kinds of things.
It is a new dialogue we have to get with the public to appreciate
how to balance the uncertainties that we are happy to talk about
with the balance of evidence which is saying yes, there is something
serious going on.
Dr Williams
110. I am disappointed that you are so defensive.
If I was working in your field full time and knew as much about
it as you do, I would want to be reassured about the Arctic ice
and so on. We did that for the ozone problem. Nobody has been
there or found any effects of it and yet people out there, politicians,
were persuaded about CFCs. There is a big consensus about it.
Why are you not on soap boxes attempting to persuade the people
or the politicians themselves?
(Professor O'Neill) I do not think we are being defensive.
I think we are trying to present the evidence with the right balance.
The example of the ozone hole is a nice one because in fact this
is a good example where scientists did work very hard to pin down
the science. There was a huge amount of scepticism about this.
People say, "Oh, it is natural. Look at the scientists coming
up with this nonsense", but scientists have pinned it down.
In this particular case the nations of the world did act and phased
out the damaging CFCs and the United States was included in that.
This was a happy circumstance in which there was a relatively
straightforward technological solution. Of course the solution
was that there were replacement chemicals and other things you
could do. The problem with greenhouse warming is that fossil fuels
are still the basis of energy production. There is no easy solution.
The other point is, and this comes back to this soap box idea
of shouting it from the rooftops, that we always have to recognise
that one piece of evidence like the melting of the sea ice to
some extent is not enough. That could occur naturally. It is the
pattern of changes and the mounting evidence that comes with it,
whereas the ozone hole is much more specific, it opens up every
spring and then closes again. There are greater uncertainties
I would say and the role of natural variability is much more dominant.
111. But in terms of the general public out
there—they take their views from Friends of the Earth and
Greenpeace, rather than from the Labour Party or from MPs or,
unfortunately, from scientists who know a hundred times as much
as those members of Greenpeace in terms of the earth.
(Professor O'Neill) Yes.
(Professor Bowen) With respect to the melting ice
in the Arctic, I do think the public are now aware that there
is such a thing as the North Atlantic oscillation and it has been
stuck in its present mode for the last 20 years and warm air is
being pumped up into the Arctic. That could switch suddenly and
as we are having mild, wet winters now, they could switch to the
Mediterranean and we could have very cold winters. If you took
it on a larger scale, possibly as a result of enhanced greenhouse
gases which would produce greater run-off in the North Atlantic,
you might produce fresh water which would freshen the surface
of the ocean and would slow down the thermohaline circulation
which pumps water up there.
112. You are telling me that you have got a
ready explanation for global warming for the Arctic melting?
(Professor Bowen) Yes, an alternative to global warming.
Dr Turner
113. Would it be fair to gather from what you
have been telling us, both verbally and in writing, that having
paleoclimatic evidence of global warming which is going on anyway
now, overlaid with man's activities, makes it very difficult to
disentangle the two processes and do you have any confidence in
scientists' ability ever to predict it with any degree of accuracy
or of governments to be able to respond to the advice if anyone
can ever agree on what it should be?
(Professor Bowen) What you are really asking me is
to disentangle natural variability from anthropogenic forcing
on which the IPCC said in 1996 that they could detect a discernible
human influence. It seems to me that until we understand all the
forcing functions, until we understand all the processes and the
feedbacks, I do not honestly think that we are going to be able
to say confidently what, for example, the global temperature will
be in the middle of the next century.
Dr Iddon
114. I just want to make a quick reference to
volcanoes. The Geological Society have suggested that large volcanic
eruptions can have a significant cooling effect on weather and
climate. To your knowledge has this been addressed adequately
in the debate?
(Professor O'Neill) I think there is ample evidence
that the eruption of volcanoes and the aerosols they release can
have an effect on climate. We detected it in the eighties with
satellite data. The thing is that these aerosols released from
volcanoes tend not to reside that long in the atmosphere so we
can represent if you like an ambient level of natural aerosols,
and in fact in doing that we have got a much better agreement
with the climate models with the recent temperature record than
we had when we did not do that. I do not think it is something
we have forgotten about. Again, it is by no means enough to account
for what we have seen. Call that a natural forcing if you like,
and that will tend to give us a climate cooling typically, whereas
what we are seeing is a warming. We need other things to get that
result.
Dr Gibson
115. If there were one thing you could tell
the Government to do what would it be, each in turn? I could give
you five but what would be the most important thing to manage
climate change as far as the Government is concerned? We have
had lots of talk but what could we do that would be effective
and win the support of the public?
(Professor O'Neill) Try to recognise that there is
a real threat of rapid climate change even acknowledging yet again
the magic word "uncertainty" and that where we can institute
changes in the way we live and the way we operate there are other
longer lasting benefits, in other words a no risk strategy that
we should inevitably try to go that way because when there are
increases in energy efficiency there are knock-on benefits and
what one then gets is sustainability.
(Professor Bowen) Energy efficiency, cut down ruthlessly
on all pollutants, and I do not include carbon dioxide as a pollutant.
Carbon dioxide is an essential part of photosynthesis and the
reason for our being here. If government did concentrate on those
things which are eminently attainable, this would be putting the
precautionary principle into action at a reasonable level.
(Dr Shackley) I agree with the other two in the sense
that we are now in the domain of solutions to the problem of climate
change. The debate has moved on. The Hague aside, the Kyoto protocol
is not going to go away. There will be negotiations. Even if the
US are not involved, it can still be ratified if the industrialised
countries get their act together. Business is taking this incredibly
seriously now, including in the United States. We are moving into
a world which will economically and socially change because of
climate change, even if climate change is not manifest in the
immediate future. The implication of that is what the government
is already doing and it needs to continue to do that in relation
to the climate change levy and emissions trading schemes. There
is a lot of exciting development in the new Carbon Trust which
is using some of the money from the levy to support new energy
technologies, renewable energy, ways of decarbonising the energy
system as well as storage of carbon by forests. There is a lot
of opportunity for captured carbon storage in disused oil and
gas fields, for example, and there are huge opportunities for
business as well. These are the areas that I think government
should continue to support.
Dr Turner: Gentlemen, thank you very much. I
apologise that we have run slightly over time. It is the loquacity
of our members, I am afraid. Thank you very much.
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