Tuesday, May 20, 2008

Comparative advantage in carbon trading

Do developing countries have a comparative advantage in carbon trading?
This is one of the questions raised by NGM's article Forests of the Tides on mangroves. (Incidentally, there was an excellent exhibit at the KL Aquaria on mangroves which we got to see last summer).
1. "Wherever they live, they share one thing in common: They're brilliant adapters. Each mangrove has an ultrafiltration system to keep much of the salt out and a complex root system that allows it to survive in the intertidal zone. Some have snorkel-like roots called pneumatophores that stick out of the mud to help them take in air; others use prop roots or buttresses to keep their trunks upright in the soft sediments at tide's edge."
2. "Bangladesh has not lost sight of that logic, putting a great premium on the ability of mangroves to stabilize shores and trap sediments. A low-lying country with a long, vulnerable coastline, Bangladesh is also land starved, with a crushing population density of 2,500 persons per square mile (2.6 square kilometers). By planting mangroves on delta sediments washed down from the Himalaya, it has gained over 300,000 acres (120,000 hectares) of new land on the Bay of Bengal."
3. For more than 25 years Jin Eong Ong, a retired professor of marine and coastal studies in Penang, Malaysia, has been exploring a less obvious mangrove contribution: What role might these forests play in climate change? Ong and his colleagues have been studying the carbon budget of mangroves—the balance sheet that compares all the carbon inputs and outputs of the mangrove ecosystem—and they've found that these forests are highly effective carbon sinks. They absorb carbon dioxide, taking carbon out of circulation and reducing the amount of greenhouse gas.

By measuring photosynthesis, sap flow, and other processes in the leaves of the forest canopy, Ong and his team can tell how much carbon is assimilated into mangrove leaves, how much is stored in living trees, and how much eventually makes its way into nearby waterways. The measurements suggest that mangroves may have the highest net productivity of carbon of any natural ecosystem (about a hundred pounds per acre [45 kilograms per 0.4 hectares] per day) and that as much as a third of this may be exported in the form of organic compounds to mudflats. Mangroves, it seems, are carbon factories, and their demolition robs the marine environment of a vital element.

Ong's team has also shown that a significant portion of the carbon ends up in forest sediments, remaining sequestered there for thousands of years. Conversion of a mangrove forest to a shrimp pond changes a carbon sink into a carbon source, liberating the accumulated carbon back into the atmosphere—but 50 times faster than it was sequestered.

If mangroves were to become recognized as carbon-storage assets, that could radically alter the way these forests are valued, says Ong. If carbon trading becomes a reality—that is, if forest-rich, carbon-absorbing countries are able to sell so-called emissions credits to more industrialized, carbon-emitting countries—it could, at the least, provide a stay of execution for mangroves.

But Ong notes that the financial incentives have to be great enough to make forest preservation economically viable. "Take Indonesia, which has the largest total area of mangroves of any country in the world. It can't afford to save them for nothing," he says. "But if the Indonesians could trade the carbon-storage potential of their mangroves as a commodity, that would create a great incentive to stop bulldozing them for shrimp ponds or chipping them for the production of rayon."

4. Eritrea was reeling from war and famine when Sato first traveled there in the mid-1980s. Since water is such a scarce resource in this arid country, Sato wondered if he could develop some form of salt water–based agriculture on Eritrea's long coastline, to help provide food for the hungry. Mangroves seemed a logical, if unconventional, choice. They occurred naturally, though patchily, along the Red Sea shore, they flourished in salt water, and camels were known to eat the leaves. If camels ate them, why not feed the foliage to sheep and goats? Grow enough mangroves, Sato reasoned, and you could provide food security for thousands.

So, like a maritime Johnny Appleseed, he began planting—and failed. All the saplings died. Undaunted, Sato looked closely at places on the Eritrean coast where mangroves were growing naturally, and he noticed they occurred only where fresh water was channeled during the brief rains that fall on this desert coast. Sato reasoned it was not fresh water the trees needed but minerals the water was bringing from inland—specifically nitrogen, phosphorus, and iron, elements in which seawater is deficient.

By conducting a few simple trials, Sato and a small team of helpers from the Eritrean Ministry of Fisheries assessed how much of the three elements mangrove seedlings needed and devised a low-tech method of supplying them. When the propagules are planted, a small piece of iron is buried alongside. So, too, is a small plastic bag with holes punched in it containing a fertilizer rich in nitrogen and phosphorus.

Now, six years on, 700,000 mangroves are growing on the formerly treeless shore of Hirgigo. Sato calls the project Manzanar, after the World War II internment camp in the California desert where, during his teens, he and his family were relocated, along with thousands of other Japanese Americans. It was the memory of older internees there coaxing crops from the arid soil that inspired him all these years later.

At Sato's Manzanar many of the mangrove trees are now well above head height, and the yellow-green coats of ripe propagules are beginning to split open, showing the plump green leaves within. The mangrove mud is sprouting pneumatophores, as if someone had sown a crop of pencils. Barnacles and oysters have started to settle on them, and crab and winkle trails crisscross the sediment. Plant a few trees, and you usher in an ecosystem. Build nature a house, and she makes it her home.

Since planting began, Hirgigo's fishermen have started to catch small species such as mullet. Ibrahim put the equation simply: "No mangroves, no mullet." And the little fish that make the mangroves their home attract bigger, predatory fish—the kind that snag in Ibrahim's net and sell for good prices in the Massawa market.

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