Examination of Witnesses (Questions 100
- 105)
MONDAY 10 NOVEMBER 2008
PROFESSOR STEPHEN
SALTER, PROFESSOR
KEN CALDEIRA,
PROFESSOR KLAUS
LACKNER AND
DR VICKY
POPE
Q100 Chairman: If we leave carbon
sequestration to one side as a technology, because I think most
of us would accept that that is a very sensible technology to
use, are there any other geo-engineering solutions that you feel
have a commercial potential, Professor Caldeira, which ultimately
might drive this science?
Professor Caldeira: I think there
are potential areas of research where there could be co-benefits.
One example, and this might also sound as far out as climate engineering,
but a number of people are looking at the potential for extracting
wind energy from high altitude winds where the wind is much stronger
and blows more steadily. One of the big challenges of that is
maintaining a tethered platform at altitude. This could not only
affect high altitude wind power, but if you are going to disperse
particles up high you would like a platform there; also to recharge
electrically powered surveillance planes you might want a platform
up there also. There might be research into maintaining high altitude
platforms that could have co-benefits where climate engineering
would be one of the benefits. I would like to take the opportunity
to comment on your point about the lack of enthusiasm here. I
think that thoughtful people are not enthusiastic about climate
engineering. Thoughtful people would like us to see deep reductions
in carbon dioxide emissions and see those reductions soon. It
is really a certain sense of despair that we are not seeing those
cuts quickly that is pushing us to consider these things. I really
look at Klaus' proposals as a form of carbon capture and storage
and personally I would not classify what Klaus Lackner is researching
as geo-engineering.
Q101 Ian Stewart: There are bodies
like the Tyndall Centre who argue that attention needs to be paid
to the phasing in of schemes in relation to geo-engineering running
alongside other abatement measures. As I understand it, Professor
Salter, amongst others, has argued that it may even be too late
to deploy geo-engineering technologies in line with this. Bearing
that in mind, can you say whether we still should go ahead with
the development of geo-engineering schemes? If so, do we have
the skills in the undergraduates and graduates that would allow
us to do that?
Professor Lackner: If your question
is with respect to manipulating the climate, I do not think we
have the skills to do this today. We should learn about it and
we should have it ready in case we need it, but I would very much
view that as an effort of last resort. We cannot solve the problem.
We cannot stop the CO2 from accumulating by changing the climate
and I would argue that this is such a complex system that you
really do not want to do that unless you really have no choice
left. If the glaciers in Iceland are falling into the ocean maybe
you have no choice, but you should not think of this as the way
you stabilise the system. That, in a way, answers your previous
question. I do not expect people to make money out of the Fire
Department so I really do not expect people to make money out
of those kinds of geo-engineering efforts.
Professor Salter: The most urgent
thing is to try to save the Arctic icecap because, if we lose
that, we have now got another very large input of warming coming
in from the sun. I think that is particularly urgent. The ice
is vanishing much more quickly than the first studies of climate
change predicted; it really is going frighteningly fast. It is
also possible that if we get very large amounts of methane released
from the seabed in the Arctic, and also from the permafrost, that
they could take over from carbon dioxide as the main driver for
global warming and then it would not matter how much carbon we
reduced, we would still have a climate change problem. I would
rather have it available too early than too late.
Professor Caldeira: To address
the moral hazard issue from before, it is not clear what an ethical
course of action would be. If we did find that the sea ice is
melting and threatening polar bears and arctic ecosystems with
extinction and Greenland is sliding into the sea, is it better
to say let's have that ecosystem go extinct, let's lose Greenland
and that will be a good motivator for people to reduce emissions,
or do you say no, we actually care about these ecosystems, we
care about Greenland and maybe we should put some dust in the
stratosphere to prevent this from happening while we are working
on reducing emissions. I do not think the ethical and moral high
ground is necessarily to say let's allow environmental destruction
to proceed unimpeded while we are trying to reduce emissions.
Q102 Ian Stewart: Professor Caldeira,
let's take this example that Professor Salter has given and you
have carried on with. If we were to address that issue, how long
would it take us to develop the geo-engineering and how much would
it cost? Does anybody have any idea?
Professor Caldeira: Nobody really
knows but the estimates in terms of cost are in the order of,
within a factor of ten, a billion dollars a year. It is the low
cost—I am thinking now of dust in the stratosphere scheme—of
this that makes it somewhat frightening because it might be so
cheap that people might want to do it because it is cheap and
easy. I think within a few years we could start getting the stuff
up there using aeroplanes or artillery shells or something while
lower cost strategies are developed. It is something that could
be deployed at relatively low cost and relatively quickly. The
question is are there unanticipated damage or even anticipated
damage that doing that would create? It is important to do the
research up front so that if you do find that there are environmental
consequences of global warming that you would like to prevent
using these approaches then you are not just creating bigger problems
and that is why we need the research.
Q103 Ian Stewart: Is there a technology
that seems to hold the most promise in relation to these matters?
Dr Pope: I wanted to come back
to the point that Professor Caldeira made that what we need to
be concentrating on is removing the greenhouse gases from the
atmosphere. Whether that is by reducing emissions or removing
them artificially, those are the key to solving the problem. On
the point about climate engineering—trying to alter the
climate to compensate and of course there is the question of unintended
consequences—many of the changes that we are talking about
are temporary. If we put aerosol into the troposphere, for example,
to seed clouds it only stays in the atmosphere for a couple of
weeks, so you have to keep putting more aerosol in. If you put
aerosol into the stratosphere it stays much longer, perhaps for
a couple of years, but you still have to keep putting the aerosol
in. When you put carbon dioxide in the atmosphere it stays around
for hundreds of years. If you are going to use geo-engineering
as a solution you have got to keep doing it for hundreds of years
because as soon as you stop doing it the warming goes up again,
so either you have to decrease the emissions much more quickly
or you have to put up with even higher warming. You have to bear
that in mind in looking at the consequences.
Q104 Chairman: We are asking you
to stargaze now in terms of which of the geo-engineering techniques
that have been mooted so far if you were a government minister
would you be urging resources to be put into? You have a new President,
Ken. What would you ask him to do?
Professor Caldeira: First of all,
if I was the new President I would be putting a small fraction
of my total effort into climate engineering, but within that effort
putting small dust particles into the stratosphere seems to be
the most promising and cost-effective approach and I would also
put some resources into looking at the sorts of things that Steve
Salter has been talking about. I would also be hesitant to pick
winners at an early stage. It is important to fund a broad diversity,
a wide portfolio, of research options and not think that we have
already thought of the best approach or even thought of the most
important negative consequences that could occur.
Professor Salter: I would agree
completely with that. I think we might need to have all of them.
In particular, we might want to have the widespread effect that
you can get from stratospheric aerosols where they are doing a
very big area which you might, in hi-fi terms, describe as a woofer.
You might also want to have a tweeter, which is the local effect
we can get from treating clouds locally. We might have the Arctic
ice to recover; we might have a particular coral reef, perhaps
the Great Australian Barrier Reef where we focus particular amounts
of cooling in one particular sea area so that the water that flows
from there keeps the coral. At the moment, however, I would be
very hesitant to attack any scheme that I did not know a great
deal more about than I do now.
Professor Caldeira: May I amend
my statement that I would also fund the kind of work that Klaus
Lackner is doing but I would fund it out of a carbon capture and
storage programme because I would not consider it climate engineering.
Q105 Chairman: The last word to you,
Professor Lackner.
Professor Lackner: I would emphasise
the carbon capture and storage and I would advise against large
scale experiments until we really understand how it works. We
are embarking on something mankind might do over the next 200
years but I doubt that we really understand what we are doing
here.
Dr Pope: Of all the solutions
that people might want to look at, it is very important to look
at all of the consequences of any solution that people might come
up with, so I would not advocate anything in particular. It is
important to try and work out what those unintended consequences
might be so that we are in the best position to make decisions.
Chairman: On that note of unanimity,
could we thank you very much indeed Professor Klaus Lackner from
Columbia University, it has been a pleasure to have you on the
video-link; to thank Professor Ken Caldeira from the Carnegie
Institution, thank you for coming to see us this afternoon; to
Professor Stephen Salter, the University of Edinburgh, thank you
very much indeed, and last but by no means least, Dr Vicky Pope
from the Met Office. We are in your debt for joining us today.
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