Messolonghi Lagoon, Greece – Yiannis Theodoropoulos spends most of his time suspended half a metre above water.
The 52-year-old fisherman, his 17-year-old son Alexis, and a hired hand, Thomas, live in a wooden shack on stilts in the middle of the Messolonghi Lagoon, in southwest Greece.
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Early each morning, Thomas collects nets put out the night before and prises fish out of them, while Yiannis and Alexis take shallow-bottomed boats to see what they have caught in their divari – a half-acre-sized enclosure of wooden poles fitted with netting that traps fish.
It is an ingenious method carried out for centuries in Greece’s lagoons. As the tide comes in, fish swim against it to eat incoming nutrients, and fishermen open up gates on the divari’s landward side to catch them. When the tide reverses, they open gates on the seaward side. Theodoropoulos fears that climate change now threatens this way of life.
“This year all the fish were held back,” he says. “I think it might be because of the heat, because there hadn’t been a heatwave like this year’s for many years … not since 1997, and the fish were held back then, too.”
Greece suffered a series of unprecedented heatwaves last summer, defined as days when the temperature soars above 35 degrees Celsius (95 degrees Fahrenheit).
“This heatwave was the longest that ever struck our country,” geophysicist Christos Zerefos told Al Jazeera. The 1997 heatwave Theodoropoulos remembers does not even rank as one of the worst. “In 1987 it lasted five days. In 2007 it was six days. And now 11 days. It keeps on increasing,” Zerefos says.
The Committee for the Study of the Effects of Climate Change, which Zerefos leads, predicted in 2011 that Greece will experience 35-40 more days of heatwaves each year by the end of the century.
Agriculture and fishing will suffer more than other sectors, the committee’s report found. In a no-action scenario, annual gross domestic product (GDP) will drop by 2 percent in 2050 and by 6 percent in 2100, amounting to an overall cost of 701 billion euros ($814bn) in 2008 prices – three and a half times the country’s GDP.
Data compiled for this report by the Athens Observatory confirm that temperatures are already rising. The observatory’s weather-monitoring station in Agrinio, 30km (19 miles) north of Mesolonghi, found that in the last 30 years average annual temperatures have risen nearly 2C (3.6F) to just below 22C (71.6F).
The impact of climate change is already apparent on Theodoropoulos’s livelihood. He rents the hut and divari from the local prefecture for 12,000 euros ($14,000) a year. This year business was so bad he had to sell a boat to help pay the rent.
“I sold the boat for 2,800 euros [$3,235],” he says. “It cost me more than 9,000 euros ($10,400) to build. But I was forced to.”
The prefecture is in theory responsible for the upkeep of the hut as part of the rental agreement, but in practice, it does not bother, says Theodoropoulos. During October, Greece experienced two waves of storms that severely weakened the hut. On one side, its wraparound deck has collapsed.
“I went to the prefecture and told them about the damage done by the last storm, and they said, ‘fix it yourself’. How? Do I have that much money?” says Theodoropoulos, who already pays 5,000 euros ($5,800) a year to renew the wooden poles of the divari. “These decks are all rotten beneath. If we have another bout of bad weather, we’ll all float away.”
The changing climate bodes ill not only for the numbers of fish that enter the lagoon, but also for its waters, which are the key to its biodiversity.
Brackish lagoons such as those of Mesolongi and neighbouring Aitoliko are formed by sweet river water mingling with seawater in the river delta. The lagoons sit between the deltas of the Acheloos and Evinos rivers.
The Zerefos Committee’s worst-case scenario predicts that rainfall will diminish by 17 percent across Greece by the end of the century, weakening rivers. This has not yet been borne out by rainfall measurements.
The Athens Observatory’s readings show rising rainfall at the Agrinio station for the past 30 years, but Kostas Lagouvardos, research director at the observatory, warns that rainfall causes are complex and can change unexpectedly.
A 2009 study commissioned by the Mesolonghi-Aitoliko Lagoon Management Authority predicts that sweet water entering the lagoons from the Acheloos and Evinos will fall by 30 percent by mid-century, making the water less brackish and more saline.
Three hydroelectric dams on the lower reaches of the Acheloos River also cause harm, says the authority’s coordinator Yiannis Selimas.
That is because the Acheloos and Evinos carry silt and sand downstream, which is deposited in the form of sandbars that enclose and protect the lagoons’ delicate water balance.
“The sandbar islands are gradually eroding, partly because of climate change, partly because silt from the Acheloos River is being held back in the dams,” Selimas tells Al Jazeera.
“To preserve them we will have to have more silt. It can happen artificially, but that requires specialised study, and we’d like it to happen naturally as it has done for thousands of years.”
More alarmingly, rising sea levels from melting Arctic ice could eliminate those sandbars altogether, turning the lagoons into open sea.
“A study done for us by the National Observatory suggests coastal areas will flood, and the river deltas of the Acheloos and Evinos appear to be especially vulnerable,” says Selimas.
“We don’t want the lagoons to turn into seawater, because brackish water has high biodiversity. We are in danger of losing species of fish, mammals, even birds.”
A 2017 study by the European Commission’s Joint Research Centre of scientists estimated that sea levels will rise by 57-81cm (22.4-31.9 inches) around Europe by 2100.
The 2009 study explains what that will mean for the low elevation of the Messolonghi area, which hosts farming on the deltas’ rich alluvial plains, and where 80 percent of Greece’s salt extraction takes place.
“If sea levels rise 50cm [19.7 inches], 64 hectares [158 acres] will be flooded by seawater. If the worse scenario of a 100cm [39.4 inches] rise is realised, the estimate is that approximately 165 hectares [408 acres] will flood, of which 132 hectares [326 acres] is inhabited and 33 hectares [81.5 acres] is farmland,” the report says.
As devastating as the implications are for the economy, they extend further.
“A healthy forest, a healthy wetland, absorb CO2, and help mitigate climate change-related extreme weather events, such as floods,” Dimitris Ibrahim of the World Wide Fund for Nature tells Al Jazeera.
Ibrahim, who heads the WWF’s advocacy on climate and energy issues in Greece, says the country is already seeing the effects of climate change.
“The summer period is increasing, meaning more drought and heatwaves – in fact, we’re seeing the first heatwaves in May now – which scientists warned we would … There will be rising sea levels and increased extreme weather phenomena.”
Theodoropoulos feeds a family of 14 with the bream and mullet he catches, and he pays two employees. He has anointed the 17-year-old Alexis to succeed him in feeding the family. A lifetime of living on the water and hoisting nets has given him back pain.
“I have my son. In another 10 years or so I’m going to rest. What can I do?” he says.
He does not appear to have contemplated how Alexis will manage in a complete collapse of the environment that allowed his generation to make a living.