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Tropical storm Fay gathers over the Georgia coast last year - but what's causing an increase in bad weather?

IT WAS back in 1998, and some terrible international weather events were unfolding.

There were floods across the world, with China the worst hit as the Yangtze River basin flooded and caused 2,500 deaths, displaced 56 million people, made 230 million homeless and caused damage estimated at a total of $30 billion. In New Zealand, the floods in July and October were the worst in 100 years, while Hurricane Mitch caused 11,000 deaths in the Caribbean and throughout Central America.

The USA also suffered, with temperatures so hot during the winter that Lake Erie (the world’s 10^th largest lake) failed to freeze over for only the third time on record. A mix of drought in Texas in the summer of 1998, immediately followed by a wet winter and spring in California (which caused a spread of soil-fungus), resulted in a cotton crop some 25% lower than in the previous year. In October 1998, the rain finally arrived in Texas. It killed 22 people and caused the worst flooding since the late 1920s. Throughout the world an estimated 16% of the world’s coral reef was destroyed.

The concept of a man-made cause linked to increasing CO² emissions was quickly identified. The news stories of the time show that while the phrase ‘climate change’ was not in common use, there was a clear view that these types of temperature changes could become a regular occurance. And the objective measure of the average global temperature*, as carried out by Climate Research Unit at the University of East Anglia with the Hadley Centre at the Met Office, showed a dramatic increase over the previous 20 years.

However, there was another explanation: El Nino.

The cyclical variation of ocean temperatures in the Pacific Ocean was well documented at the time. El Nino is defined as a change of 0.5 degree in ocean temperatures, and lasts between nine months and two years.

The El Niño-Southern Oscillation – to give it its proper name – struck again in 2002, when Vietnam had its worst drought in 27 years. In the USA, 26 states suffered drought, with one of the lowest harvests for 30 years. Australia was particularly badly hit, with the economic impact reducing GDP by 1%, the equivalent of $2bn.

The complexity and inter-relationship of El Nino and global warming does not make analysis easy, but potentially there a causal link, with the increased recent frequency of El Nino caused by global warming. Or maybe it’s the other way round, because in 1998 the air temperature temporarily increased by 1.5^oC.

No one really believes that global warming is a myth, but almost-breathless news stories seems to be accelerating and the impact of the climate change on worldwide political agenda has, arguably, passed both international terrorism and recession as the top issue for world leaders.

The credibility of the science is rarely contested. The IPCC (International Panel on Climate Change) is a UN body, and is comprised of 100’s of respected scientists from many different disciplines. Some are climate specialists, but there are a number of others (chemists, biologists) as well. And in the UK there is very little challenge to the global-warming idea although, in several parts of the world, it is strongly contested.

From a scientific perspective, the climate change discussion is hideously complex. Significant factors affecting the actual temperature of the earth include the heat retained by the oceans, the reflective nature of both polar ice-caps, as well as the ability of the earth to process CO². However, the actual measure (the temperature of the earth) is pretty simple to understand, rising steadily through peaks and troughs since 1980.

But the data for just the past 10 years makes for a far less dramatic impression, and some statistical tricks are played and charting begins in the El Nino year of 1998 (while excluding the current year on the basis that the data is only available until August for 2009) then actual temperature begins to fall away quite steadily.

So does this suggest that global warming is a myth?

No, it doesn’t. Clearly the world has increased its temperature over the past few decades, and placing the blame on greenhouse gases, primarily CO², has much scientific evidence in its favour. However, climatologists are keen to point out that their science is very complex and extremely difficult to predict. Those in the CO² denial camp still believe that there are other explanations for the current increases, including increases sun spot activity. A recent Channel 4 documentary presented this controversial argument.

What is clear is that the data by itself is open to very wise interpretation.  Whilst 1997 and 1998 might have been cause by El Nino, there is no discernable rise in temperature over the past 10 years. This presents a challenge for the scientific community, as every local flood or brief heat wave can be seen as an example of long-term, man-made environmental change.

Outside the propeller-head brigade, no-one really thinks that there is a conspiracy by the Western democracies to inflate concern about global warming.  But there is a real risk that Western industrialised guilt will overshadow other, less dramatic problems, including the big killers of Africa – diarrhoea, HIV and Aids, and malaria.

In 2004, an attempt was made by Bjorn Lomborg (the poster-child for the alternative climate change lobbyists) to apply sober economics to the question of how Western aid can be most effectively targeted at the developing world. This analysed the impact of aid budgets, essentially measuring how much good they would deliver for their cost.

The top of the list was

-          Control of HIV and Aids

-          Tackling malnutrition through distribution of micronutrients

-          Trade liberalization

-          Control of malaria

At the bottom were the Kyoto Protocol and carbon taxes.

The scientific community is currently in a safe place with climate change. There is little challenge to the fundamental principle of man-made causes, principally CO² emissions. But if the next few years see a continuing plateau of global temperatures, then a backlash to this received wisdom is quite possible.

* The data is for global temperatures (rather than specifically northern or southern hemispheres) for an average across each year.