PARIS: Climate change made torrential rains that triggered deadly flooding in Libya up to 50 times more likely, new research said on Tuesday (Sep 19), noting that conflict and poor dam maintenance turned extreme weather into a humanitarian disaster.

An enormous wave of water struck the city of Derna after heavy rains on Sep 10 overwhelmed two dams, washing whole buildings and untold numbers of inhabitants into the Mediterranean Sea.

Scientists from the World Weather Attribution group said a deluge of the magnitude seen in northeastern Libya was an event that occurred once every 300 to 600 years.

They found that the rains were both more likely and heavier as a result of human-caused global warming, with up to 50 per cent more rain during the period.

In a report looking at floods linked to Storm Daniel that swept across large parts of the Mediterranean in early September, they found that climate change made the heavy rainfall up to 10 times more likely in Greece, Bulgaria and Turkey and up to 50 times more likely in Libya.

But researchers stressed that other factors, including conflict and poor dam maintenance, turned the "extreme weather into a humanitarian disaster".

To unpick the potential role of global warming in amplifying extreme events, the WWA scientists use climate data and computer modelling to compare today's climate - with roughly 1.2 degrees Celsius of heating since pre-industrial times - to that of the past.

WWA scientists are normally able to give a more precise estimate of the role climate change has played - or its absence - in a given event.

But in this case they said the study was limited by a lack of observation weather station data, particularly in Libya, and because the events occurred over small areas, which are not as accurately represented in climate models.

That meant the findings have "large mathematical uncertainties", although the study said researchers were "confident that climate change did make the events more likely", because of factors including that current warming is linked to a 10 per cent increase in rainfall intensity.

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