Periods of extreme heat are becoming more frequent, more intense and longer-lasting as climate change warms the planet, the World Meteorological Organization (WMO), the United Nations' weather agency, said, drawing a direct comparison with Europe's hot summer of 1976. Parts of Europe are currently enduring their fifth heatwave of a summer already marked by drought, wildfires and record-breaking temperatures.
A pattern with no historical precedent
"Extreme heat is becoming more frequent, more intense, lasts longer and covers much wider areas than in cooler climates of the past," said John Kennedy, Head of Climate Monitoring and Prediction at the WMO, speaking at a press briefing in Geneva.
Kennedy said the current heat pattern across Europe, the world's fastest-warming continent, reflects the interaction between a persistent pattern of high-pressure systems across the Northern Hemisphere and a warmer overall climate. High-pressure systems trap warm air, reduce cloud cover and block the movement of cooler air, allowing heat to build over large areas for days or weeks at a time.
El Niño not a factor this year
Kennedy said El Niño, the natural climate phenomenon that typically boosts global temperatures, is not contributing to this year's heat in Europe, since conditions in the tropical Pacific are currently neutral.
How 1976 compares
Kennedy noted that June 1976 broadly featured a similar pattern of high and low-pressure systems to those observed this year, but said the outcomes are markedly different due to decades of global warming since then. "The picture for 1976 was one of a few isolated regions above the average temperature in a much colder world," he said. Today, he added, "the picture has reversed," with much of the planet experiencing above-average temperatures and only a few isolated cooler regions.
Warm seas and dry soil compounding the heat
Exceptionally warm seas and dry land are pushing temperatures higher across Europe, Kennedy said. Marine heatwavesin the Mediterranean and in waters off western Europe are driving warmer conditions on land, feeding additional heat into persistent high-pressure systems. Dry soil compounds the effect further, since land heats up faster once moisture is depleted.
"Many of these factors are coming together to give us the record heat we are seeing this year," Kennedy said.
Source: Reuters
