Development & Aid, Environment, Tierramerica

Climate Change Just One Factor in Coastal Erosion

BUENOS AIRES, Oct 12 2009 (IPS) - To understand the link between global climate change and coastal erosion requires an integration of the otherwise reductionist specialization on the issue, says Argentine scientist Jorge Codignotto.

The Paraná River delta in eastern Argentina is the only one in the world that is not disappearing, and that is due to deforestation for cultivating soybeans, explains geologist Jorge Codignotto, a former member of the Intergovernmental Panel on Climate Change, in this interview.

“All of the deltas in the world are on the way to disappearing,” except for the one formed where the Paraná River runs into the Río de la Plata (River Plate) estuary, said Codignotto, who sat on the IPCC from 1999 to 2007 and has spent years studying Argentina's coastal areas.

“By deforesting the Yungas jungle, in the northwest, in order to grow soybeans, the Bermejo River continues to provide more sediment that ends up in the delta. If that situation continues, in 2050 the delta will extend to Buenos Aires, and it will be polluted,” he said.

This is one example of the factors, in addition to climate change, that affect nearly 5,000 kilometres of shoreline – from the Rio de la Plata estuary to the Beagle Channel – that make Argentina one of the 25 countries with the most coastline.

It is necessary to “diagnose” coastal erosion in a “holistic” way, and the government should regulate human activities in those areas, says Codignotto, who holds a PhD in geological sciences from the University of Buenos Aires, and is lead researcher for the National Council of Scientific and Technical Research.

TIERRAMÉRICA: What is the current outlook for Argentina's coasts?

JORGE CODIGNOTTO: The Argentine coast is affected by a broad phenomenon of erosion, which has been increasing since the 1970s.

This has normally been attributed to global warming, because as the planet heats up – the causes of which are being debated – the anticyclones (areas of slowly rotating high atmospheric pressure) move towards the poles, which means more frequent and more intense storms in more southerly areas that normally don't have them, so there are more waves, more energy, and stronger currents in coastal areas.

But there is also an increase in erosion from human causes.

TIERRAMÉRICA: How does the rising sea level influence erosion?

JC: Actually, the sea level rises just three millimetres per year, but the important thing is the domino effect: there are more coastal currents that cause erosion, and it is raining more in some places, and that carries soil towards the sea, which modifies ecosystems.

It is estimated that in 2025 there will be one billion more people on the planet and a notable shortage of food, because the key ecosystems will have collapsed. Ecosystems can adapt, but they need more time.

By 2025, the United Nations calculates that 85 percent of the world's population will be living in coastal areas, which are inherently unstable and will suffer even more from human pressures.

And there is another problem: pollution. A 1,000 to 1,200-metre stretch of the Río de la Plata coast in this country is contaminated with mercury, cyanide, chromium, detergents, etc., from waste that is not treated because it would be very expensive.

Fourteen million people in this country drink water that comes from the Río de la Plata. At the rate the delta is advancing, it is going to reach Buenos Aires by 2050, with all its pollution.

TIERRAMÉRICA: How is erosion affecting the Argentine coast?

JG: Erosion varies from area to area. On the Buenos Aires coast, concrete houses and coastal avenues have collapsed. That is basically money dumped into the sea out of ignorance. People build in coastal areas, but aren't aware that the land moves in all directions and more so along the coasts.

It's hard to understand that coastlines change. However, when the Spaniards reached the Río de la Plata, they sailed to Escobar, 50 kilometres north of what is now Buenos Aires. And 19,000 years ago, you could reach the Malvinas Islands (known by local inhabitants as the Falklands) on foot.

Another problem is flooding. The town of General Lavalle, in the bay of Samborombón (Buenos Aires province), is practically at sea level. It has tidal canals that fill with rubble and they sell off the plots. This, in a context of rising sea level, makes no sense.

TIERRAMÉRICA: In the city of Buenos Aires they added, on average, 20 hectares of land per year with coastal landfill since 1925. What do you think of these efforts to gain land from the river?

JC: We should spend money on something that is more useful and economical, such as discouraging people from populating coastal areas.

TIERRAMÉRICA: Is it feasible to educate the population about these issues?

JC: First we need legislation for rational land use. In the resort cities of the Buenos Aires province coast there are often streets perpendicular to the shore. When it rains and southeasterly winds come up, the runoff isn't absorbed by the sand to prevent erosion, but instead ends up out at sea, leaving big channels on the beach – a phenomenon that is worsening due to the destruction of the sand dunes in order to facilitate access to the beaches.

In Villa Ostende, 365 kilometres south of the city of Buenos Aires, they designed broad, green areas along the coast that every so often have a depression for rainwater to accumulate and filter into the ground.

TIERRAMÉRICA: Do municipal governments have adequate solutions?

JC: No, but one thing we do have is Decree 3202 on coastal management, which the province of Buenos Aires enacted in November 2006.

We are lucky that our Civil Code, with regard to the coasts, is based on the ancient Roman concept of the “tow line route.” Back then, a 35-metre wide strip along seas and rivers was reserved for public use, so that horses pulling tow lines could move boats that couldn't use sails so close to land.

The Argentine coast cannot be privatised thanks to Dalmacio Vélez Sarsfield, author of the Civil Code. Although on occasion it has been bought off.

TIERRAMÉRICA: Is there any possible long-term solution?

JC: Information with a holistic outlook is essential. There are many experts, but specialisation tends to narrow people's focus. Specialists should integrate their studies with the broader context. And the government must establish regulations.