The cost of losing coral: no drop in the ocean

By Bryan Walker 21/10/2009


Climatechallenge Perhaps it will register if it’s expressed in money terms. The latest issue of the New Scientist carries an article reporting an estimate of  the loss of the world’s coral reefs at $172 billion per year. The estimate comes from the work of Pavan Sukhdev and colleagues. He’s an economist with the United Nations Environment Programme, and head of a European Commission study called The Economics of Ecosystems and Biodiversity (TEEB). It’s an international project to raise awareness about the economic benefits of biodiversity. I hadn’t come across its work before, but last month it produced a report TEEB Climate Issues Update. It’s a subset of early conclusions relating to climate change and a fuller report will follow next month.

The report addresses what it sees as three critical issues for the Copenhagen negotiations. First, the imminent loss of coral reefs. Second, an early and appropriate agreement on forest carbon.  Third, the compelling cost-benefit case for public investment in ecological infrastructure (especially restoring and conserving forests, mangroves, river basins, wetlands, etc.)

I might examine issues two and three another time, but for this post I’ll stay with coral reefs. Hot Topic covered John Veron’s lecture to the Royal Society a couple of months ago on the parlous state of coral reefs and the worse dangers ahead as ocean acidification worsens. The TEEB report confirms that outlook, quoting the Royal Society statement. But it goes further in indicating what the effects on human welfare will be.

Coral reefs are an integral part of an extensive and vital landscape of coastal ecosystems which includes estuaries, marshes, mangrove forests, dunes, seagrass beds and lagoons. These ecosystems are  biologically highly productive.

Estimates of the total number of people reliant on coral reefs for their food resources range from 500 million to over one billion. Some 30 million of the world’s poorest and most vulnerable people in coastal and island communities are totally reliant on reef-based resources as their primary means of food production, sources of income and livelihoods.

Coral reefs are often likened to ‘oases’ within marine nutrient deserts. Productivity of coral reefs may be many thousands of times higher than in the surrounding open sea. This high productivity makes the reefs critical to the survival of both marine and coastal ecosystems. It is also the underlying reason why they contribute so significantly to human welfare.

The benefits which analyses have so far attempted to quantify include fisheries, shoreline protection, tourism, recreation, and aesthetic value.  But the report says when an ecosystem is close to a critical threshold, it may become impossible to value because of uncertainty or even ignorance about the potential consequences of nonlinear behaviour.

The reported science suggests that anthropogenic emissions have brought the coral reef ecosystem to the brink of potential irreversible collapse. Thus we may have encountered our first major global ecosystem ‘threshold’. At such a point we need to consider the ethical and social dimensions of value as well as the economic. Right now it can be said:

’The imminent demise of tropical coral reefs is predicted to be an extinction event of proportions never before witnessed by humankind. The loss of this critical ecological infrastructure will damage the productivity of global fisheries and the chances of stock survival. It could thus lead to future food crises. It will impoverish over 500 million people who depend on coral reefs for their livelihoods.’

 This section of the report concludes with the rather forlorn urging that global political leaders and their climate negotiators recognize and address the risks of irreversible loss of most of the world’s tropical coral reefs by:

• providing explicitly for coral reefs in measures for coherent climate change adaptation solutions for coastal areas when establishing climate adaptation strategies and agreeing adaptation funds

• working towards agreeing on more ambitious CO2 reduction, that will improve the chances of survival and recovery of coral reefs.

It can be added that less than 350 ppm CO2 concentration is the level that the Royal Society scientists saw as needed to ensure the long-term viability of coral reefs.