91av

El Niño is back. Well, probably. The see-saw in weather conditions
across the Pacific Ocean is tipping once again, and its baleful effects could be
upon us within six months. That’s the verdict of most of the climate modellers
who have been number crunching temperature data from the middle of the
Pacific.

Four years ago, the “El Niño of the century” wreaked havoc worth
$32 billion around the world, to homes, farming, forestry and tourism.
Many governments are still bruised. This time, forewarned by timely predictions,
they are likely to be thinking up plans to counter the threat. Fatalism in the
face of the weather may be a thing of the past, but there’s a danger that we’ll
replace it with something worse.

The stakes are high. Indonesia won’t want to repeat the burning of Borneo’s
rainforests, which having been dried by El Niño, choked its neighbours in
smoke. And as President Robert Mugabe campaigns for re-election in Zimbabwe he
won’t want the drought that often coincides with El Niño to turn existing
food shortages into famine. The UN, in a report last year, urged governments to
“prepare now for the next El Niño”. But prepare how, exactly?

The certainties are few. For a start, El Niño forecasting is still a
very tentative affair. Not all climate modellers working on the case are
confident that El Niño will arrive as predicted in six months’ time.
Those that are, say that it will be weaker than before. But that could be wrong,
too. Six months before the last El Niño, few of the models predicted that
it would be anything out of the ordinary
(91av, 31 May 1997, p 6).

El Niño’s impact isn’t always predictable either. It’s supposed to
bring drought to East Africa—but try telling that to the Kenyans. At the
height of its last appearance, the country was hit by massive rains in the
middle of what should have been the dry season. Widespread floods brought Rift
Valley fever to cattle herders and cholera to the capital.

And on the other side of the world, in Costa Rica, the environmentally savvy
government advised moving large herds of cattle from the area normally hit by
drought. Sadly, the rains failed right where the hapless animals had been moved
to. Cattle died by the thousand.

The danger, now that governments have got wind of the importance of El
Niño, is that they look at the forecasters’ predictions and then take the
wrong action. For scientists, it may be a triumph to be able to announce a
probability of, say, 70 per cent that El Niño will arrive in six months.
But for governments it creates serious problems. You can look pretty
stupid—and waste a lot of money—acting to forestall an act of God
that never shows.

Sure, climatologists are making excellent progress. They are getting to grips
not only with the dynamics of El Niño, but also with the vagaries of the
Asian monsoon, the North Atlantic Oscillation and other features of the global
climate which are slowly emerging from the chaos of our weather. But there is
much to learn before the dream of worldwide long-range weather forecasting
becomes a reality.

Forecasters have long associated El Niño years with drought in India.
But that link also seems to have broken down. Why? Is it, as some have
suggested, caused by a recent flip in the North Atlantic Oscillation, which has
strengthened the jet stream over Asia? We need to know, too, what causes East
Africa’s hit-and-miss relationship with El Niño. Has it got something to
do with precisely when the phenomenon kicks in? Or perhaps how strong it is?
It’s a confusing picture that global warming may already be complicating.

There are some things that prudent governments certainly should be doing.
Unblocking the rubbish-clogged drains of Nairobi and putting the city’s cholera
teams on alert makes good sense, as do refilling the grain stores of Zimbabwe
and banning people from setting fires in the rainforests of Borneo.

But the overriding lesson may be that while vulnerable countries should
prepare for the worst, they shouldn’t bank on it happening. Last year the UN
bemoaned “a general lack of belief among potential forecast users around the
world in the reliability of [El Niño] forecasts”. Maybe that scepticism
isn’t so bad. Like stereotypical Englishmen, countries should learn to carry
umbrellas when the forecast even hints at rain. Just don’t open them until the
rain starts to fall.