Warming threatens Mediterranean

A diver takes part in a waste spotting operation on the eve of a cleaning campaign of Marseille's "Vieux port" harbour sub sea floor in the Mediterranean sea, on November 6, 2015. AFP PHOTO / BORIS HORVAT

TANGIER, Morocco/BEIRUT: Cradled by three continents, one of the Earth’s most bio-rich marine environments, and a vital source of economic activity, the Mediterranean Sea is facing serious threats that will affect all 22 countries it connects. The world’s largest inland sea, the Mediterranean possesses its own unique characteristics that make it at once both very fragile and resilient.

It is a semiclosed basin, with only the narrow Strait of Gibraltar allowing water to flow into the Atlantic Ocean. This is the chief element of the sea’s fragility, according to Antonio Troya, director of the Center for Mediterranean Cooperation at the International Union for the Conservation of Nature.

“The water renewal in the Mediterranean region has a very long rate of about 80 years. To put it in perspective, one single drop that enters the Mediterranean through Gibraltar will be back out again in 80 years,” Troya told The Daily Star on the margins of the MedCOP Climate 2016 conference in the Moroccan city of Tangier.

This oceanographic feature makes the Mediterranean Sea vulnerable to increases of temperature and decreases of precipitation. The outflow occurs through deep water layers, aggravating the accumulation of debris, especially plastics, found in upper layers of the basin.

According to a research report conducted in 2015, entitled “Plastic accumulation in the Mediterranean Sea,” there exists between 1,000 and 3,000 tons of floating plastic in the Mediterranean, a buildup that is “comparable to the accumulation zones described for the five subtropical ocean gyres.”

The temperature of the Mediterranean’s shallow water has risen 1 degree Celsius over the past 40 years and is expected to increase a further 2.5 degrees Celsius in the next 70 years, an IUCN study indicates.

Slow as it may be, this small increase in temperature is enough to generate significant impact on both marine and human conditions, according to Troya. The warming process, as he described, is gradually occurring from the southern rim to the northern rim and it is leading to two interesting phenomena: “tropicalization” and “meridionalization.”

“Tropicalization means as the water temperature is increasing, more species from mainly the Red Sea, tropical areas and the Atlantic area are entering the Mediterranean, where they find good conditions,” Troya explained.

This colonization by the new “invader” species could, in all likelihood, disrupt ecosystems and overrun native inhabitants.

Meanwhile, meridionalization represents the redistribution of species in the Mediterranean basin, mainly from the southern rim to the northern rim, which is witnessing a slower pace of temperature increase.

“So the species that like the cold temperature are moving back, their distribution range is narrowing little by little, which is a problem; this could lead to their extinction” Troya said.

Unfortunately, it is difficult to project the exact long-term effects of these changes. “We can make some predictions and try to elaborate by modelization of the species on how this could occur ... but what is going to be the dimension of those movements” is not fully known, Troya said.

“The Mediterranean is going to face a tough scenario. There are clear changes happening and the main issue that was discussed in COP21 in Paris and will be discussed in COP22 in November is: How are we going to cope with this problem?”

Although in recent years the tangible danger of climate change has finally gained the global attention it deserves, the process of dealing with its consequences has been slow, and in some cases the impacts have reached a point of no return.

According to Troya, independently of the efforts to maintain the average increase of temperature below 2 degrees Celsius, the world will keep facing an increase from now until 2100. “We have put so much CO2 in the atmosphere that now the effects are going to occur even if we are now taking measures to avoid higher increases in temperature,” he said.

But on a positive note, Troya said the Mediterranean Sea harbors enough species and ecosystems that it can respond and adapt to the changes it is undergoing.

“This is a very important feature of the Mediterranean ecosystems. We have such a huge variety of species – some of which are inconspicuous yet essential – plants, habitats, etc., that there is an internal capacity to respond positively to those impacts. It’s encouraging,” he said, adding that ecosystems in other regions have a narrower capacity of response.

However, Troya insisted that the Mediterranean Sea needs human cooperation in order to increase and maintain its natural resistance capacities to climate change, which can be done through conservation and the implementation of adequate tools and policies.

Through these tools, the southern Mediterranean societies in particular will be able to cope with climate change, Troya added.

The CMC director also warned that although concern exists at a political level, considerable work and cooperation between Mediterranean countries is needed and it is up to world leaders to ensure that occurs. “The potential solutions are there but you need to construct the social, political and economic means to make them real.”

A version of this article appeared in the print edition of The Daily Star on July 23, 2016, on page 11.




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