Rainfall last month was a third of the norm, and total rainfall so far this season was 40 per cent of the average, raising concerns for farmers but also adding weight to fears about desertification as the lack of rain persists year after year. 

Environmentalist Alan Deidun notes in The Sunday Times of Malta today that this is the third consecutive dry year and the situation can have serious implications on the island’s natural wild flora and fauna and on agriculture.

Rainfall last month was just 35.3mm, equivalent to just 30 per cent of the average for December since the 1930s.

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The total volume of rainfall recorded so far during this rainy season (which, for recording purposes, kicks off on September 1) amounted to some210mm, which was just 40 per cent of the average total for a whole rainy season.

Given that rains normally subside in this part of the world by the end of March, it is highly unlikely that this season’s rainfall will come anywhere close to the average total of 520-550mm, Prof Deidun observes.

This will make 2017-2018 the third dry season in a row, following 2015-2016 (with total rainfall below 300mm) and 2016-2017 (total rainfall was below 400mm).

To compound matters, a blistering wind has removed any surface moisture that the island’s topsoil might have absorbed and reduced terrain to a tinderbox well ahead of springtime. 

"It is not just farmers who find themselves holding the short end of the stick with such weather but also the country as a whole. The desertification of the island will gain traction in these arid conditions, with the reduction in the topsoil’s productivity over time, the stunting of plant growth and fewer roots compacting soil particles together," he says.

The desertification of the island will gain traction in these arid conditions

Local freshwater communities, such as those found along watercourses, and those associated with freshwater rock pools and semi-natural wetlands, such as Għadira, Simar and Magħluq, will face the brunt of reduced rainfall, especially once summer kicks in.

"The general dearth in natural vegetation, and in blooming, come next spring, will reverberate on other food web components, including insects and pollinators, effectively resulting in a vicious cycle for plants."

Each summer, he points out, witnesses the shrivelling of scores of mature trees, including Aleppo pines, almonds and even carobs, whose death occurs unnoticed.

"When will we finally realise that our dependence on desalination (for tap water) will not spare us completely from the ravages of changing climactic patterns?"  

TECHNICAL EXPLANATION

The Gozo Weather Page, an observatory of weather patterns, yesterday also discussed the current worrying situation on its Facebook page.

It said it has been generally warmer and drier than average so far this season.

"The mean temperature since last September 21st is currently at 16.8 C, significantly higher than the climate average of 15.9 C. With just over 200 mm of rain since last September 1st, we have received less than half of what we would normally have gotten by now."

It explained that the main suspect behind the weather situation is an atmospheric pressure pattern called the Arctic Oscillation, which circles the high Northern Hemisphere.

Its lower edge is known as the North Atlantic Oscillation (NAO). Together, they influence the path and strength of the jet stream - a very strong air current that flows west to east across the northern hemisphere, altering temperature and precipitation as portions of it dip southward or crest northward, the observatory said.

The NAO can either be negative or positive. This year, it is positive. A positive NAO oscillation causes a stronger than normal Azores High to prevail out over the Atlantic. On the other hand, the Icelandic Low is abnormally weak. As a result of this, the jet stream is keeping to the north. This allows warm air from over Africa to rise freely towards the Mediterranean. It also prevents cold fronts from descending from the north and clashing with the warm air locally. Conversely, northern Europe has been experiencing more frequent windstorms. The jet stream has been locked in that position by the positive NAO since mid-autumn.

A variable NAO is part of a cycle.

"We have had similar autumns and winters on numerous occasions in the past. The most notable include 1990, 1996, 1998, 2000, 2009 and 2015. The latter was record-breaking."

Scientists, however, have discovered a very serious abnormality, it adds.

"The oscillations are becoming increasingly unpredictable. They have been varying more dramatically recently. Scientists say the loss of Arctic sea ice due to global warming is causing the Icelandic Low to weaken.

"This would mean a more frequent positive NAO, and hence an increase in the frequency of warm and dry winters for the Maltese Islands. Summers will also become longer and hotter because of this. Others have noticed a correlation with sunspot activity. They have not yet proposed a mechanism whereby sunspots would directly alter the Arctic Oscillation.

Projections for the future?

Winter has many weeks to go, so the oscillations could shift, but as winter progresses, the chance of a shift becomes less likely.

"The previous two winters have also been notable drier, with 2015 in particular, being the driest on record. We are still suffering from the lack of water from those years. Over time, it will become difficult to regain what we have lost in the past," the Gozo Weather Page warned.

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