Examination of Witnesses (Questions 70
- 79)
WEDNESDAY 8 DECEMBER 2004
PROFESSOR DAVID
POWLSON, PROFESSOR
ALASTAIR FITTER
AND DR
AUSILIO BAUEN
Q70 Chairman: Gentlemen, you are
very welcome indeed. For the record, from the Biosciences Federation
we have Professor David Powlson from the Rothamsted Research Institute
and the British Society of Soil Science—I think in my days
at University I must have read one of your books about soil, that
is why I have got an allotment—Professor Alastair Fitter
from the University of York and the President of the British Ecological
Society and Dr Ausilio Bauen from Imperial College. You are all
very welcome indeed. I apologise in advance that we are a little
bit time constrained, because there is likely to be a vote some
time in the next 20, 25 minutes or thereabouts. Would you give
us a couple of minutes on the effects of climate change on UK
biodiversity? What are the key things that you think we should
be aware of?
Professor Fitter: Our inability
to predict what is going to happen, I think, is the big problem.
Q71 Chairman: It happens to politicians
all the time.
Professor Fitter: You are used
to that, I realise that, but scientists like to have greater certainty,
and we do not like the situation when we do not have it. We have
some pretty good indicators of what is going on. There are some
marked changes already taking place even though the really significant
climate change is perhaps only 10 to 15 years old. Even at that
time we can see marked changes in natural systems. The obvious
changes are in timing of events, which in themselves are curious
rather than anything else, but they are the canary in the mine;
basically they are telling us that the natural world has noticed
what is going on, and they give us real cause for concern for
the longer term implications. We are already seeing changes in
range boundaries, so species are moving north, and that means
eventually they hit buffers, because if you hit the north coast
or the top of a mountain, or whatever, you cannot go any further.
The big problem is (a) we do not know exactly what will happen,
and that is very common in these things, obviously, but (b) we
do know that different species respond in quite different ways,
and that means that there can be a disruptive effect within communities
so that some things will profit, some will suffer. There will
be big changes in the way that communities are constructed, and
that will have implications for the way in which they function,
and that means that the way the global ecosystem serves us to
keep the world ticking will change, and that is a real concern.
The compounding problem is that this is all happening against
a background of an extraordinarily human affected environment
anyway. We have extremely fragmented habitats so that parts of
the habitat which are suitable for a species may be separated
by large areas which are unsuitable from the next possible patch.
You can imagine that if climate change makes the first patch unsuitable
it will make it very hard for that species to get to another possible
island which is a refuge, as it were.
Q72 Mr Mitchell: The Watership Down
syndrome?
Professor Fitter: Absolutely.
What a perfect scenario to capture that. You are absolutely right.
It is exactly that. We also have other insults taking place, such
as nitrogen deposition and other forms of pollution, slow erosion,
etcetera, you name it. Think of something nasty and we are doing
it to the environment in various ways, and that is making it even
more likely that species will find it difficult to respond effectively
to adapt to climate change. The final real complication is that
when this last happened, which is about 12,000 years ago, when
climate warmed dramatically, we know exactly what did happen.
We have a wonderful fossil record telling us, and there was a
stately progress of species responding to this, migrating across
Europe as the ice retreated. We are going through the same process
now of rapid warming, but the problem is we now have huge numbers
of species in situ which are not native to this country. Gardens
hold something like 10 times as many species as there are native
plants in Britain. There is a reservoir of species waiting to
escape and invade natural communities, and some of them have done
so already, and some of them are very serious problems already,
and that will be a continuing complication. Just to put it in
context, in the US it is estimated that invasive species cost
the economy well over $100 billion a year.
Q73 Chairman: What are they, in case
I have got any in my back garden?
Professor Fitter: You will have,
for example, Japanese knotweed somewhere near you; you will have
Himalayan balsam too, but think of the new pests that are coming
in: sudden oak death, New Zealand flatworm. There are lots of
these things which are appearing now. These are brought about
by the fact that we are very good at moving species across the
globe—from New Zealand, for example, to here—which
could never possibly have got here otherwise. In the last model
we have, which is the post glacial situation, when the ice retreated
and everything warmed up, everything was migrating under its own
steam, but we have short-circuited that entire process now. We
are saying if anything wants to grow here, "Come on, we will
bring you here, you can have a free ride and see how you do."
Some of them will do hopelessly, and they will not survive, but
others—and we can not predict which—unfortunately,
will become serious pests.
Q74 Chairman: You mention the word
adaptation. In policy terms of you giving advice to the Government,
what should they do? Should they concentrate on adaptation or
mitigation as a strategy, or are you going to say we have got
to do a bit of everything?
Professor Fitter: You have obviously
got to do both. It would be crazy to do one or the other. We have
no option but to accept that over the next 30 years or so, whatever
is an appropriate timescale, but let us take that sort of timescale,
there is going to be a major change taking place enforced upon
the biodiversity of the UK, and we have to allow the natural communities
in the UK to adapt to that. We also have to mitigate those effects
longer term, but in that relatively short term what we need are
policies which allow some of those negative impacts which are
synergistic with climate change to be minimised, because climate
change is going to happen anyway. We want to reduce nitrogen depositions,
we want to reduce habitat fragmentation, we want to reduce the
problem of invasive species, and so on and so forth, all those
things. If you like, that is the mitigation which allows the systems
to adapt.
Q75 Patrick Hall: Are we assuming
that climate change means a reduction of biodiversity in Europe.
Professor Fitter: It could mean
an increase, but it might be rather an alarming increase. The
probability is that it will result ultimately in a reduction,
but it may not. We cannot predict that. It will probably produce
reductions in some places but not in others.
Q76 Alan Simpson: I wanted to move
to the issue of transport, carbon emissions from the fuels that
we use and the significance of biofuels. I am not sure how long
ago it was now, but the Committee went to look at some of this
in relation to Brazil, and it was quite a humbling experience,
I think, for us to realise that Brazil has been running the entirety
of its public transport system on biofuels since 1930. They took
us through some very interesting calculations that showed that
there was more carbon absorbed in the growing of sugar cane than
was generated in the cutting, processing and then consumption
as fuel, so they had a net carbon gain equation. I am just wondering
if you have done any calculations on the significance of biofuels
in the UK, because we cannot run on a presumption that suddenly
we will all grow sugar cane. In a sense we as a community are
getting very different messages about the significance of biofuels,
one part saying you start to displace traditional agriculture
and you have a significant amount of cost; you look at the costs
in terms of agro-chemicals that go into the scale of production
and you have a massive additional hit. In fact, it is not even
an economic proposition. We would be better off going for short
crop coppicing. Somewhere, as the non-scientists, we have got
to do some serious number-crunching. Have you done any of this
work?
Dr Bauen: Yes, we have actually
done some of this work, and we have looked at other situations
in Brazil and elsewhere in the world. You are correct when you
say that sugar cane is, first of all, a very efficient crop. It
has very high yields. In southern Brazil it reaches something
like one hundred tons per hectare, which is an extremely high
yield. Secondly, when the ethanol is produced at the processing
plant it uses the left over fibre after the pressing of the cane
to provide energy to the process. So it is practically an entirely
renewable energy process. That is why you get something like 90%
reductions in carbon emissions when you substitute gasoline with
ethanol in Brazil. As you say, some people may claim that you
get a benefit because you are storing carbon somewhere in the
system, in the soil, for example. That could be replicated in
tropical countries with other species. If we go to the UK, a temperate
climate, the situation is slightly different because of the crops,
the products we can grow. The two principal options in the UK
for the production of biofuels today are bio-diesel from rape
seed and bio-ethanol from wheat grain principally, possibly to
some extent from sugar beet. Both of these options are from crops
that have lower yields compared to cane. Also, the crops require
a certain amount of fertiliser, which requires energy and has
emissions to the atmosphere as well, and the process to produce
the fuels is fairly energy intense. It depends how they are fuelled.[20]
Clearly a renewable energy to the system will affect the carbon
balance. But if we look at what the carbon balance for the biofuels
produced in the UK is we could say that for bio-diesel—if
you were to substitute fossil-diesel you would get a reduction
of up to about 60%. The range in the evaluations we have done
is between 40 and 60% in terms of emissions reduction. For bio-ethanol,
because the process is more energy intensive, depending on the
technologies used, the carbon emission reduction compared to gasoline
is somewhere between 20 and 50%. Several reports and work have
been done in the UK on this. Recently the Low Carbon Vehicle Partnership
produced a report on bio-ethanol from wheat which shows you can
go up to 50% or more reductions in emissions. Compared to Brazilian
ethanol the reductions in emissions are lower. Is there a need
to go a biofuel route in the UK given that the emission reductions
are lower? Is there a potential for that? I think there are several
things that you need to consider. Biomass can also be used and
grown for producing electricity and heat. Probably in the short
term the biggest benefit in terms of carbon reductions will be
from substituting heating oil—where there is no gas connection
for heating purposes—and substituting coal-generated electricity
possibly through coal firing. You could use probably a variety
of residues and wastes from agriculture and from the forestry
sector to fuel the heat and electricity sector. If you used energy
crops for the electricity sector, you could get 90 to 95% emissions
reduction compared to a fossil alternative. But if you wanted
to go the energy crop route to supplying, for example, wood-chips
for heat and for electricity, then you would have to grow a short
rotation coppice. Short rotation coppice is a new crop. It is
less established. Yields are making progress but are still not
commercially viable. There is a need to develop this route, but
for heat and electricity what you want to do is dedicate your
residues and your wastes to this route for heat and electricity.
If in the short-term there is also a need to decarbonise the electricity
sector. If you take the Government targets, for example, in the
UK climate change programme, going to 60% reductions will essentially
mean doing some back-up table calculations entirely decarbonising
the energy supply sector, and the business and the domestic sector
practically, if you want to achieve that 60%. Is that feasible?
Probably at some stage transport will have to be tackled. You
can improve efficiency through vehicles—that is the first
thing to do. Then you can also have an input in terms of renewable
fuels and that is something that will be probably necessary, because
if you introduce high efficiency vehicles what will happen is,
because there is a trend in growth in CO2 emissions
from transport, the high efficiency vehicles will only help you
stabilise the emissions from the sector rather than reduce them.
If you want to lower them you need a renewable fuel input.[21]
Q77 Chairman: It seems you could
short-circuit a lot of this very complex description you have
been giving us by building more nuclear power stations and making
better batteries?
Dr Bauen: These are alternatives
as well. You could entirely decarbonise the electricity sector
through a nuclear route. You can significantly reduce emissions
from the energy supply sector, practically reduce them to zero,
if you built sufficient power plants. Will that be viable? Will
that be acceptable? To what extent? Most likely it will not be
enough to tackle also, let us say, the heating demand. You could
have a system in the future that is all electric: electric for
driving appliances, etcetera, electric heating and electric vehicles[22].
Also, with regard to electric vehicles, what appears to be the
case is that batteries have not delivered in terms of costs, have
not delivered in terms of range, in particular to be able to let
us say satisfy customer demands and long distances especially.
That is why I think I advocate the hybrid route, the diesel hybrid
route in particular, is a fundamental development. Biofuels would
only be able to supply a fraction of the fuels that we need in
this country. Optimistically, about a third, if you consider energy
crops and all other residues and wastes, and that is including
also efficiency gains in vehicles. The efficiency gains will be
fundamental; they will have to be obtained through some form of
electric drive tank in any case. But decarbonisation options in
the electricity sector and batteries in the transport sector will
not be able to provide us with the full answer to achieving ambitious
carbon reductions. Just going back to one point in terms of biofuels,
if we were to use one million hectares, which is less than about
20% of arable land in the UK, we could produce roughly 5% of our
road transport energy needs based on current crops and technologies,
I would say that we are talking about roughly a 2½% emission
reduction based on commercial biofuels. One thing that is very
important is that there is technology development in the biofuels
sector, and that in order to expand the resource base, a biomass
resourced base to take advantage of that, you have to go towards
lignocellolosic biofuel production routes; so you need to be able
to use, for example, not only the wheat grain but the wheat straw,
and this requires enzymatic processes that are now pre-commercial
in the US and being developed. The other one is a route that allows
you to produce synthetic diesel using residues and wastes and
energy crops such as short rotation coppice—it is a gasification
process followed by a gas to liquid process, a process which is
commonly used in the energy/oil industry. If you want to be able
to get more out of biomass you will eventually have to innovate,
and I think we are moving along this curve. That also allows much
better emission reductions.
Q78 Chairman: Professor Powlson wanted
to come in.
Professor Powlson: Could I add
to that. In terms of land use, we need to remember, of course,
that in the UK and throughout the EU about 10% of arable land
is set aside at the moment; so that is a potential use, if you
like. We have done some simple calculations. If you use not quite
all but 80% of current set aside land in this country and grew
biomass crops in it—we were thinking of electricity generation,
not liquid fuels, and this could be coppice willows, and so on,
or miscanthus, which is a big grass that looks very much like
sugar cane, which gives a very big yield and needs very small
inputs, very interestingly—if you use that area of land,
or a bit less than current set aside, you could provide, with
current technology, about 3% of the country's electricity. There
are huge ways in which you could increase that. If you started
using extra land, partly because things like sugar beet might
not become profitable in the future, there is some grass land
that is potentially available and you brought in other wastes,
and so on, you could get to 12%.
Q79 Chairman: Let me ask you a practical
question. You have got land set aside scattered everywhere and
you have to produce 3% of the nation's electricity at possibly
one or two points on the map?
Professor Powlson: No. I do not
think going to one or two points is the way to do it. You could
go for a few big stations or lots of small ones, and many people
who know much more about that end of things than I do seem to
think that many small ones is the way that makes sense.
20 Footnote by witness: The impact of the process
depends on how the energy is provided. Back
21
Footnote by witness: This can be achieved in the short-term
through the bio-diesel and bio-ethanol routes mentioned. Back
22
Footnote by witness: However, heating demand is currently
strongly dependent on natural gas. Back
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