Considerable publicity has been given to high-efficiency electric light
bulbs, which are much less wasteful of energy than normal filament bulbs.
However, I find many of the arguments for them, so often put for-ward by
environmental organisations, very unconvincing. It is no doubt true, as
an advertisement in New ÐÓ°ÉÔ­´´ claimed, that low-energy bulbs costing
£22.95 (as against 39p for a filament bulb) are equivalent in their
light output to an ordinary 75-watt bulb for a use of some 20 per cent of
the current used by the filament bulb. This appears to be a substantial
saving, but would it seriously reduce electricity bills?

I live in a tall, 100-year-old terrace house in central Cambridge. This
is well insulated on both sides by neighbours who keep their houses warm
– as I also contribute to their comfort. The narrower walls at the back
and front of the house are mostly window, which is, of course, double glazed
(to keep out student noise as well as keeping in the heat). The roof is
well protected by a thick layer of fibre glass. Our only source of energy
is electricity, which is used for space heating (night storage), cooking
and hot water, as well as light. We appear to have 41 lights through the
house. Were I to replace all these by low-energy bulbs the capital outlay
would be well over £900. If this sum were invested in a building
society it would produce an annual, tax-free income of over £100.
This is more than I spend on illumination, and for replacing filament bulbs
as well.

I realise that it would be foolish to install expensive low-energy bulbs
in places where they are seldom used – the spare rooms, cupboards, lavatories.
But even in most of the rest of the house they would be a doubtful investment.
Electric bulbs of the ordinary type may be inefficient, but the current
they use is comparatively small. I would reduce my electricity bill more
by cutting room temperatures by a degree, by occasionally switching off
one heater, or by taking fewer hot baths.

According to my calculations, it would begin to pay to convert any ordinary
light only if it were used for considerably more than 1000 hours a year.
Using smaller bulbs and switching off more rigorously might prove more effective.
Finally, is the increased energy costs of manufacturing low-energy bulbs
always allowed for?

Greater savings might well be obtained in factories, stores and offices
where lights burn for 8 or even 24 hours a day. This is true, but in many
such places efficient fluorescent tubes are already in use. Actually, in
my own house I have already installed a tube in a dark kitchen, and I am
sure many householders have done the same. So the situations where low-energy
bulbs might be used are often overestimated.

One other point should be borne in mind. The heat produced by filament
bulbs is not all ‘wasted’. It helps to warm some buildings. In fact, with
really good insulation, this may be all that is required to produce acceptable
warmth. With low-energy lights, supplementary heaters would sometimes be
necessary.

We should concentrate on obtaining real economies. In many existing
buildings, particularly factories, insulation could be greatly improved.
Public buildings, including offices, stores and hotels are generally overheated.
Here economies could produce results several orders of magnitude greater
than would any substantial increase in the use of low-energy bulbs in our
houses.

Kenneth Mellanby was the first director of Monks Wood Experimental Station,
set up by the Nature Conservancy, and founder-editor of the journal Environmental
Pollution.

What the results on our climate will be no one knows, though many have
opinions. Complex and expensive computer models suggest figures for global
warming of between 1 and 9 Degree C by the year 2050; this scatter of results
reinforces my view that, while these exercises may be fun, there is so little
firm data that back-of-envelope calculations would be more sensible. Nevertheless,
a substantial number of responsible scientists believe that there is a serious
possibility that these rises in greenhouse gases will produce disasters
on a scale that mankind has never faced before. The warming of the oceans,
and the melting of Antarctic and Greenland ice, could cause the ocean levels
to rise, drowning much of the low-lying and densely inhabited land throughout
the world. Climatic changes could make the grain belt of America too dry
to grow cereals. Global food shortages, with an increasing world population,
could be horrific.

If these disasters are possible, it is sensible to work out how the
output of greenhouse gases could be controlled. It is likely that concern
about the ozone layer will result in the end of the release of CFCs, but
plans for controlling carbon dioxide seem to me to be totally ineffective,
and those to control methane (which is potentially more important) are nonexistent.

Suggestions made so far by international conferences, governments and
environmental groups concentrate on reducing carbon dioxide output by more
efficient use of energy and economy in the use of fossil fuels. These economies
are highly desirable, as world resources are limited and need to be conserved.
But many of the suggestions are of a very minor importance. Thus, to substitute
fluorescent tubes for light bulbs has been widely advocated, though the
result would be minute. Other economies would be useful, and in Britain
we might reduce our energy consumption by 20 per cent without any serious
effect on our comfort and our industry. Other advanced nations could do
the same. But this would soon be counteracted by the increased output from
developing countries, which have little alternative to using fossil fuels,
particularly coal, the most polluting and carbon-dioxide generating of all
energy sources.

The next suggestion is that we should make more use of renewable sources
of energy, particularly solar and wind power. This again is sensible, and
in Britain could contribute as much as 20 per cent of our needs. Any greater
development of wind power, like the windmill ‘farms’ of California, would
so damage the environment as to be unacceptable. More importance could be
given to the cleanest and most efficient energy source – hydroelectric generators.
These have only a limited potential in Britain, but worldwide could be of
major importance. The trouble may be that developments such as were proposed
in Tasmania will be opposed by the very environmentalists who are most vocal
about energy pollution.

Forest clearance has clearly added to carbon dioxide levels. Planting
more trees temporarily mops up the gas, though it is released when the wood
is burned or decays. Strict preservation of tropical rainforests, and extensive
planting world wide is highly desirable anyhow (it may give some time for
instituting other actions), but in the long run it will have little effect
on global carbon dioxide levels.

All these proposals have the advantage of being in themselves valuable,
whether we are concerned about the greenhouse effect or not. But even if
fully implemented they will have only a minor effect, delaying the rise
of carbon dioxide for a few years. If we are serious about the problem,
something more drastic is necessary.

The only practicable programme, I believe, would be for the advanced
countries to reduce greatly, and eventually to stop, the use of all fossil
fuels. Some reduction could be made, as has already been indicated, by economies,
by greater efficiency and by the use of renewable sources of energy. But,
in the end, we would have to depend on a vast increase in nuclear power.
It is therefore unfortunate that, just when the British government has discovered
the greenhouse effect, it has become less committed to the nuclear solution.
It will have to reconsider its position.

The public is unduly worried about the dangers of nuclear power. These
dangers, exacerbated by alarmist television programmes, are generally exaggerated,
but even the worst estimates do not compare with the most alarmist forecasts
of the results of global warming. So the nuclear scenario must be taken
seriously.

Critics have suggested that if Britain produced all its electricity
from nuclear power, it would reduce carbon dioxide output only by about
a third. I believe that the figure could approach 100 per cent. Electricity
could be used for all domestic heating and power, and by most of our industry.
It could also power most of our transport. Obvious uses are for an increased
railway network, trams and trolleybuses in towns and cities. Even with present
techniques, electric cars could make three quarters of the journeys made
at present. With more demand, better vehicles would soon be available. Electric
lorries would take goods from rail terminals to their (nearby) destinations.
This programme would have the additional advantage of reducing air pollution
almost to zero, and reducing road building and so safeguarding much of the
countryside.

I believe this programme to be practicable, but the nations of the world
may decide it is too expensive and disruptive to existing industry. In fact,
it might be easier to devise a programme of mass population movements and
great changes in the pattern of food production than to persuade all nations
to make the radical changes in their economy which would be necessary to
control the output of greenhouse gases. If so, they may console themselves
with the knowledge that there is a substantial amount of serious scientific
opinion, particularly in the US, which believes that even with the projected
rise in greenhouse gases no serious warming is likely to occur.

At least for the present they could comfort ourselves with the thought
that it may never happen. This is at least more honest than suggesting that
even the more ambitious proposals of the United Nations will have any effect
on the rising levels of greenhouse gases.

Kenneth Mellanby was the first director of Monks Wood Experimental Station,
set up by the Nature Conservancy, and founder-editor of the journal Environmental
Pollution.