 here can be little doubt that human-inspired
global warming is happening. Any other reading would require
a completely new geographical theory of the relationship
between carbon dioxide levels, climate, and the way the Earth’s
natural systems have worked since the formation of the planet.
So it is not just a question of how recent temperature measurements
show global warming, which they certainly do. The evidence
of links between climate and carbon dioxide levels is written
on the history of the planet since it was formed. To deny
it you virtually have to re-invent geography and geology
as subjects.
The problem is that by chucking so much carbon dioxide and
other gases which trap heat we are fiddling with a mechanism
that is fundamental to the Earth’s ecosystem.
Human-induced increases in atmospheric carbon dioxide levels
began with large scale burning of tree coverage. Ten thousand
years ago, for example, practically the whole of the UK was
covered by trees (so much for the ‘naturalness’ of
the British landscape!). However, even using the year 1800
as a base, carbon dioxide levels have increased from around
275 parts per million to over 360 parts per million today,
a change of around 30 per cent. That is a big increase given
the effect of carbon dioxide levels on climate.
In addition to changing atmospheric concentrations of carbon
dioxide and other ‘greenhouse’ gases, there are
various short term and longer term influences on climate.
These include changes in the way the Earth ‘wobbles’ on
its axis as it circles the Sun, the short term impact of
dust thrown up by volcanoes and the occasional big meteorite
strike, and changes in the amount of sunshine.
However we can see the big effect on climate by comparing
temperatures on Earth to the moon. Despite being the same
distance from the sun the temperature on the moon itself
is around 35 degrees C lower than the Earth – this
difference indicates the heating impact of the greenhouse
gases.
Besides the comparison with the moon, another planetary
comparison can be made between Venus and Mercury. Mercury,
which has no atmosphere, is much closer to the Sun, yet its
surface temperature is actually cooler than that of Venus.
Venus, of course, has a thick atmosphere which includes a
lot of carbon dioxide.
There are other potential explanations of global warming
waiting in the wings. The ‘solar cycle’ theory
is one. This says that changes in the levels of sunshine
account for recent changes in temperature. The UN-backed
Intergovernmental Panel on Climate Change (IPCC) says that
it takes all these influences into account, and its models
suggest that human influences generate the large bulk of
the changes in temperature over the last 100 years.
As time goes on there is less questioning about the record
of increases in global temperature in recent decades. All
of the hottest global years in recorded history have occurred
since 1990 and the 20th century was the hottest century over
the past thousand years. Less is known about short-term variations
in temperature before around 1000 AD because of shortages
of tree-ring data.
Estimates of future temperature increases made by the IPCC
average on the most plausible scenarios in the two to three
degrees over the next 100 years. Median projections for sea
levels come in at around 40 to 50 centimetres over the next
100 years. These figures depend on various assumptions, and
certainly some influences, such as the rate of melting glaciers
and ice caps, are subject to considerable uncertainty. Because
warmer air holds more moisture rainfall is likely to rise,
which is associated in many models with an increase in hurricanes
and violent storms.
Of course we might be less lucky than the median estimates
made by the IPCC. Scenarios (like the film The Day After
Tomorrow) that involve the triggering of a big freeze in
the northern hemisphere because of the diversion of the Gulf
Stream, are cast by many as alarmist. However the problem
is that we are making such a big change to our ecosystem,
we have to ask ourselves, just how much of a risk do we want
to take?
We are going to experience significant increases in sea
levels. This is not good news for rich countries which will
have to spend a lot more on flood defences for heavily populated
areas and organise a retreat from other low-lying zones.
It will be disastrous for developing countries with large
river delta populations and positively terminal for many
small island states. One sixth of the votes in the UN General
Assembly come from small island states.
What we can say with reasonable certainty is that rising
sea levels and shifting rainfall patterns offer the possibilities
of severe disruption of human societies as well as the type
of biodiversity patterns (birds, animals, plants) to which
we have become accustomed. The longer that we delay taking
radical counter-measures, then the worse will be the outcome.
While US policy makers, driven by Republican scepticism
of ecological doomsayers, are being obliged to recognise
the probability of human-induced global warming, they tend
to argue that the cost of combating the problem is greater
than the problems that will be caused. In a much publicised
general assault on environmentalist priorities, Bjorn Lomborg
in his book The Sceptical Environmentalist said that environmentalists
have exaggerated environmental threats. He argues that money
would be much more cost-effectively spent on providing clean
drinking water for poor Africans rather than reduction of
carbon dioxide emissions. The UN Johannesburg Conference
on the environment endorsed this logic in 2002. On the other
hand why are these two items alternatives to each other?
One might as well pose spending money on educating people
about state-of-the-art energy efficiency techniques rather
than invading Iraq!
Perhaps this brings home the point. Tackling global warming
may not be that costly if people take the problem seriously
in their own lives, as well as if Governments take it seriously
in their own day-to-day activities. Citizens could became
experts in energy efficiency the way that people are now
experts in DIY. It continues to amaze me that if you work
in an office or industry you will be expected to go on all
sorts of professional training schemes, yet there is not
a single training scheme for (the very many) people who make
workplace decisions about what energy systems or new buildings
to order. There are already a lot of low-carbon technologies,
ranging from making sure housing estates run on energy efficient
energy generation systems to using super energy-efficient
(but still zippy) motor vehicles. This Government has set
a target of reducing carbon dioxide emissions by 50 per cent
by 2050. Arguably, even this target is not good enough. Nevertheless,
a target is there, but the means of achieving this target
are still to be made clear.
The global warming problem may not be that difficult or
expensive to solve, given the low-carbon technologies that
already exist. The problem is attitudes. Perhaps therefore
a bit more doomster-mongering might not go amiss in order
to grab people’s attention.
A major problem is the solutions, about which there is fierce
debate among the interest groups. Curbing carbon dioxide
emissions is the biggest single priority. Options which can
achieve this include energy efficiency, renewable energy
sources and nuclear power as non-fossil sources. There is,
and could continue to be, an increasing trend to using natural
gas in place of higher-carbon fuels coal and oil leading
to reductions in carbon dioxide emissions in countries such
as the UK.
Many of us do not relish the prospect of a world becoming
dependent on nuclear power which would itself lead to uranium
resource crises and geopolitical problems such as we see
surrounding oil in the Middle East. We have heard about wars
for oil. What would wars for nuclear power be like? In that
case we could simply be swapping one dangerous problem from
another.
The nuclear power industry sense that there is a competition
for funds to subsidise non-fossil sources and so are helping
the campaign against wind power which is by far the cheapest
renewable energy at present capable of large-scale implementation.
Organisations like Friends of the Earth and Greenpeace have
thus put resources into backing wind power. Any greens that
decide to equivocate in the face of opposition run a very
severe risk of losing credibility in their anti-global warming
strategies. We have to give enthusiastic and well-resourced
backing to various other renewable energy technologies, including
solar power, biofuels, wave power and tidal power. Either
that, or we shall encourage nuclear power.
Of course the great sleeping resource is energy efficiency.
If only everybody was an expert in energy efficiency techniques
we would be making very good progress in curbing rises in
energy demand, because then much more energy efficient equipment
and buildings would be put into use. However, as yet there
is not even an accredited energy efficiency training scheme
for the vast number of people who take energy equipment and
building procurement decisions in commerce, industry and
the public services.
Yet this would be a very cheap way of making significant
progress. It is a measure of our complacency and lack of
real motivation to tackle the challenge of climate change
that we have so far failed even to ensure people go on energy
efficiency training schemes. Indeed, the sheer economic sense
of energy efficiency measures, as well as the declining cost
of renewable energy sources, make a nonsense of claims made
by people like Bjorn Lomborg that countering global warming
is too expensive. |
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