We have gone through a cold spell in
Britain, with heavy snowfalls in many parts of the country. I knew,
then, that it was coming and it did come -- right on
the first day: a newspaper article reassuring us that these
fluctuations in weather conditions are no more than noise and do not
affect the well-established existence of man-made global warming.

I will not discuss this or similar
articles because it is evident that a local short-term temperature
change is meaningless against the long-term pattern. I am, though,
interested in the predictability of the appearance of these stories
in the media. The campaign on global warming is on and it has to be
more explicit in moments like this when our subconscious may make us
waver just so faintly. Lest we forget.

The article in the Daily Telegraph said that this spell of bad weather was not simply irrelevant, but
was yet another confirmation of global warming. Curiously, it is a
feature of man-made global warming that every fact confirms it:
rising temperatures or decreasing temperatures, drought or torrential
rain, tornadoes and hurricanes or changes in the habits of migratory
birds. No matter what the weather, some model of global warming
offers a watertight explanation.

For a scientist like me, this sounds
fishy. I imagine that there are a good number of models, each with
different assumptions and results, but we are never given a general
view of these models, what data they use, how their results compare
and where and when their predictions apply. The impression is that
science popularisers cherry-pick whichever happens to provide the
results that match the news of the day.

One very useful tool in this respect
has been the conceptual change from global warming to the more
adaptable one of climate change. The bigger the target, the easier to
hit it. Somebody should take care that the target is not so big that
it becomes impossible to miss.

I was away for my Christmas holidays in
Spain recently, and there I had more first-hand evidence of the
campaign. I met a fellow scientist whom I had not seen in many years.
I knew he had been working on carbon accumulation in soils. When he
began this work at the end of the 1980s, global warming was starting
to make the news. He naturally thought that this was a study of great
potential interest. He carried on for years, during which the
political situation around the issue changed.

The conclusion of his investigation is
that, globally, the ability of soil to accumulate carbon is 100
percent greater than the current estimation. Here is a piece of
science of great relevance to the hottest issue of the moment and one
that deserves to be looked into in detail, as it affects our
predictions substantially.

The response of the research
institution in which my colleague works was to refuse to publish his
results. There was no peer-review of the methods or science in the
work. My colleague’s track record shows that he is a competent
scientist with numerous papers published in highly-regarded
international journals. The quality of his research was not the
issue. The decision was political. His laboratory is directly
dependent on the regional government in that part of Spain, and in
this government’s agenda global warming features prominently. My
colleague’s results were seen as possibly undermining the strength
of their case.

This is not an isolated case. Research
institutions have issued statements positioning themselves in the
matter. They want to be in -- in with the media, in with public acceptance, in with Government policies, in with those who allocate funds.

Ethics is a central issue in the global
warming debate, which is all about protecting future human
generations. But ethical considerations also prescribe that research
institutions should not manoeuvre to make the best of their
opportunities at the cost of coercing researchers. Science’s goal
is truth about nature and this can only be found in a climate of
intellectual freedom.

Global warming has become a powerful
political tool. One can see the reasons. Proving
it wrong (if wrong it is) is
sufficiently difficult to allow using it for quite a long time. There
is an element of personal guilt, as we all contribute to global
warming, but not too much. Basically it is the rich multinationals
which are responsible. Thus we are called both to a cathartic
personal conversion and to a noble struggle against the evil
polluters of our fragile planet. All this helps to suppress the
dissatisfaction of what otherwise could be a life empty of worthwhile
goals. Global warming is therefore an immensely appealing cause.

However, if we are really concerned
about the Earth’s future, here is another serious danger: a large
meteorite impact.

The earth has been struck by large
meteorites regularly, albeit with decreasing frequency. The impact
record is well documented and there is little doubt about the
frequency of such events. We have learned about it from a number of
sources. In some cases, the actual impact crater has been preserved
and we can measure the age of the impact. In other cases the crater
has disappeared, presumably because plate tectonics movement has
caused the corresponding crust slab to sink below the crust, but
there are signs of the impact in other parts of the planet as the
debris settled and generated rocks of measurable age.

Finally, we know about the number of
large bodies going around in the Solar System and their probability
of hitting planets. After all, the planets were formed by accretion
of matter in which larger bodies kept capturing smaller ones passing
by. A sizeable proportion of the mass of the planets was added by
large impacts. The reason why large impacts become less frequent is
that planets have been clearing the solar system of these smaller
bodies by incorporating them.

Well then, statistically, one of these
impacts is overdue. A large meteorite impact is much more lethal than
global warming, if only because the effects are so swift: immediate
and complete destruction locally and extremely severe destruction in
days to months around the globe. For a complete description of the
effects of such an event one can refer to Walter Alvarez’s book
Tyrannosaurus Rex and the Crater of Doom, which tells the
story of the unfolding of the hypothesis of a meteorite impact
causing the mass extinction at the end of the Cretaceous period. It
is great fun to read.

There is recent evidence of these
phenomena. In 1994 we witnessed the collision of the Comet
Shoemaker-Levy 9 with Jupiter. In 1996 the Earth had a near-miss with
an asteroid which missed us by about 450,000 kilometres, an
equivalent in time of four hours. This asteroid was discovered only a
few days before the near-miss.

Bear in mind that there are thousands
of asteroids near us, of all sizes, and they can cause devastation
ranging from local to planetary scale. The Spaceguard and Near-Earth
Object programmes in the US are tracking them. Currently, the ESA is
preparing a mission called Don Quijote to test the deflection of an
asteroid by impact with a spacecraft. Other models of defence have
appeared in the media. However, pleas by scientists for more funding
have been futile.

Why aren't environmentalists
interested? Even a rather small asteroid would cause a local disaster
that would make the worst oil spill a laughable matter by comparison.
The science is there, the catastrophic effects are there. But
something is missing-- there are no baddies. Who is to be blamed if a
big rock drops out of nowhere? And what am I supposed to do about it?
The problem and the response are distant and impersonal. They do not
generate emotion and thus the asteroid menace has no value as a
political weapon.

But, who knows? An intelligently
orchestrated campaign could spiral into an ever-present news story
which pricks our consciences and makes
Small-Solar-System-Body-Counter-Impact policies a political hot
potato, dominates the government's research budget and even provides
thousands of jobs. The time to start is now.

Javier Cuadros is a specialist in
earth science. He works in London.