Warmest October in decades may signify global changes

Records tumbled as both Ireland and Britain experienced the warmest October in decades, and in some cases, centuries

Records tumbled as both Ireland and Britain experienced the warmest October in decades, and in some cases, centuries. The usual autumn chill was forgotten in many places with October's average temperatures almost matching those of September.

The Met ╔ireann weather station at Rosslare achieved an average temperature of 13.5 degrees, matching the previous warmest October in its 45-year history. Many other stations had their warmest October since 1969, according to Mr Peter Lennon, a Met ╔ireann climatologist.

Temperatures reached about 2 degrees above the 30-year 1961-1990 average which is taken as "normal", Mr Lennon said. "Month by month it is all within the variability that is expected," he added, but overall temperatures are consistently rising.

The common wisdom, and now many climatologists, hold that the reason for this change is global warming. "I think there is general agreement that global warming is happening and the trend is likely to continue," Mr Lennon said.

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Weather experts in Britain take a similar view given the stunning October temperature record set there. Last month in Britain was the warmest since records began in 1659. Britain's long term average is 10.6 degrees but October 2001 outstripped this by a full 3 degrees.

The Republic had also been set to break all existing records but temperatures dropped during the last few days of the month. This in turn helped to drag down the monthly average, Mr Lennon explained. Temperatures still registered two degrees above normal for most Irish weather stations, however.

Rainfall totals overall were also above average for October, Mr Lennon pointed out, typically running about 125 per cent of normal. Kilkenny got a real soaking during the month with 177 per cent of normal rainfall. It was generally drier in the north, however, with some stations running at or below average. Sunshine totals were also well ahead of what is typical of October, with Casement Aerodrome enjoying its sunniest since 1994.

These weather statistics fit in well with those usually presented as indicative of global warming. The typical climate change model says that average temperatures are rising and will continue to do so for at least 50 years.

The cause is given as a gradual rise in the levels of carbon dioxide and other "greenhouse" gases in the upper atmosphere, released by the burning of fossil fuels and also by intensive agricultural practices. Once in place these gases act like a blanket, trapping warmth from the sun and preventing it from escaping into space.

Climatologists have been slow to attribute this gradual warming trend to a genuine change in climate. Weather can be notoriously variable and a few years of warmth might well be followed by a cool period, causing temperatures to level off.

This scepticism has gradually given way in the face of accumulated statistics, which have shown a relentless rise in average global temperatures. These are averages, however, and mask the high temperature spikes. The five hottest years on record have all occurred during the 1990s, in turn making it the hottest decade on record. Since the mid-1990s there have been fewer record years, yet no one is suggesting that climate change has reached its peak.

It is this which this week has brought officials from 150 countries to a climate change meeting in Morocco. It follows on from earlier meetings and accords in- cluding that hammered out at Kyoto, Japan. Consensus that global warming is happening is easy to achieve; what to do about it continues to cause problems.