There will be no Shark Week without Sharks

ROTMAN_N13VZweb_1Grace Hanley, OECD Environment Directorate

As an American, it’s nearly impossible to go through summer without hearing the chatter or joining in on the festivities around “Shark Week.” In case you haven’t heard of it, it’s an annual week-long television series produced by the Discovery Channel that features all sorts of action-packed shark videos. People host parties carving shark heads out of watermelons, while sporting fin hats and snacking on all sorts of marine-themed appetizers. It’s a week to celebrate and learn about these amazing creatures that have been around for over 400 million years, surviving 5 major planet extinctions. But right now, sharks are fighting against becoming the sixth major extinction, and it’s our fault.

It’s important that we expose the ugly truth about the endangerment of sharks so that we can start taking action to adequately protect them.  To start, humans are their number one predator.  This is largely attributed to overfishing—and illegally for that matter.  Humans reportedly kill 100 million sharks each year. As highlighted in “Racing Extinction,” a film that exposes the threats to shark endangerment, wildlife trade is second to the drug market in terms of profit.  This makes conservation an even greater challenge, as there are significant economic incentives for traffickers.

To make matters worse, sharks have a low reproduction rate and thus cannot recover their populations quickly or easily. For some species, such as whale sharks, maturity  is reached at the age of 30, and most are caught before they have the chance to repopulate. In extreme cases, the wait can be a century—no, that’s not an exaggeration. The Greenland shark, which was recently reported to shatter the longevity record as the longest lived vertebrate, is predicted to live for more than 400 years.  With this considered, the females becoming ready to reproduce after they turn 156 seems to prove that it really is all relative.  However, it also speaks to the challenges of reproduction, as it takes a substantial amount of time.

Over-fishing affects even deep-sea sharks, as they are targeted by the cosmetic industry for their liver oil, which has a desirable moisturizing appeal. On top of this, sharks are also exposed to threats directly caused by humans such as climate change, pollution and habitat destruction.

We should care because biodiversity matters and sharks play a key role in balancing their marine ecosystems. In fact, they have an efficient method of preying that is also beneficial to other marine life. They target the old, sick and slower fish, which helps maintain the health of other species populations.  So contrary to their Jaws-inspired portrayal of being human-threatening cold-blood killers of summer beach-goers, sharks tend to target their feedings in a strategically balanced manner. Hence, our deep fear of sharks is unfounded, as the likelihood of humans being attacked by sharks is extremely low.

We need to be realistic about our fears and the statistics that support them. Despite the fact that it is also quite unlikely, we are much more likely to be killed by fireworks than sharks. Yet, we intentionally play with fire to celebrate events such as national holidays and then act as if stepping into the ocean is a summoning for certain death.  The truth is we are much more aggressive toward sharks than they are to us and that needs to stop. With only 3% of the 500 species of sharks known to attack humans, we shouldn’t be so worried about attacks.

However, we should be worried about losing sharks because we need them. Without sharks, the marine ecosystem will lose its balance as it loses its top predator. Removing sharks will trigger a trophic cascade effect on the marine ecosystem, with the potential to permanently alter it.  The presence of sharks—and even the fear they incite, has a positive influence on ecosystems. For example, a group of scientists in Hawaii found that their presence encouraged turtles to graze over a broader area of sea grass rather than focus on the best quality of sea grass and deplete a concentrated area, which they would do had they not had the lingering threat of sharks influencing their feeding patterns.

The stability of our planet requires a balance—and unfortunately, humans tend to be at fault for disturbing that balance. Maintaining a healthy equilibrium of biodiversity is critical to the well-being of the planet and we have the power to responsibly control this, so long as we are willing to change our habits. The enthusiasm for Shark Week is a positive example of celebrating our biodiversity, but sitting down to a “delicacy” meal of shark fin soup shows we still have a long way to go. If we want to continue celebrating our biodiversity, it is important that we educate ourselves on the best ways to protect it.

The good news is, now is the perfect time to act. In 2010, the Parties to the Convention on Biological Diversity (CBD) declared 2011-2020 to be the “Decade of Biodiversity.” More importantly, the CBD set forth the concept of mainstreaming biodiversity to eliminate the idea that biodiversity and ecosystem services are separate from the goals of development and growth. In November of this year, the Parties will meet again in Mexico for COP 13 to discuss the integration of biodiversity into relevant policy sectors.

It has become increasingly evident that the biodiversity within our ecosystems is a vital component to our life and we must implement policies that not only reflect that message, but also sufficiently protect it. Moreover, ecosystems have proved to be adaptable in both positive and negative ways as species have become transient due to changes in their habitats caused by climate change, pollution, and other factors. Therefore, the importance of a global consensus that encourages the integration of biodiversity protection into legislation will be an integral part of our sustainable development as it will allow us to collectively protect our planet and shared heritage.

Useful links

OECD work on fisheries

What does mainstreaming biodiversity mean?

IDB-2016-logo-En Before there was the Insights blog, there were the Insights books. One of the first, on sustainable development, mentioned “a magical place, seemingly untouched for thousands of years”, on the Poland-Belarus border. Well, this “last remaining fragment of a primeval forest”, Białowieża National Park, is about to be touched, by loggers. The decision has sparked an impassioned debate, in Poland and far beyond. Forests seem to be anchored deep in the psyches of many peoples. There is even a theory that the story of the Garden of Eden refers to deforestation in the Middle East 10,000 years ago, and three millennia later, The Epic of Gilgamesh would describe how the gods curse Sumeria because the hero cut down the sacred forests.

The OECD is as Jungian as the next intergovernmental organisation, but on International Day for Biological Diversity we’re angsty about the loss of forests and other forms of life for material as well as subjective reasons. Biodiversity worldwide is in decline as the pursuit of economic growth and development leads to the conversion, and in many cases over-exploitation, of natural resources for inputs to production and consumption.

The theme of Biodiversity Day this year is “Mainstreaming biodiversity; sustaining people and their livelihoods”. According to World Bank figures, “natural capital accounts for an estimated 30% of total wealth in low income countries compared to only 2% in OECD countries”. Developing countries could learn a few (negative) lessons from what happened to the developed countries on their way to OECD status. The European Potato Famine of the 19th century killed in more or less direct proportion to the lack of diversity in the poor’s diet, with a million victims in Ireland where a third of the population relied almost exclusively on potatoes for food. The Dust Bowl that devastated the North American prairies in the 1930s was in large part due to farmers destroying the grass that held the topsoil in place.

If biodiversity is so important, and neglecting or damaging it so harmful, why don’t countries “mainstream” it?  For a start, although preserving as many species as possible goes back as far as Noah’s Ark (based on Gilgamesh), biodiversity as a scientific concept is recent, dating from a 1985 US National Research Council/National Academy of Sciences forum on biological diversity, while the term “biological diversity” itself first appeared in Raymond F. Dasmann’s 1968 book A Different Kind of Country.

Even so, most of us probably have a pretty good idea of what biodiversity means. But what about “mainstreaming”? Outside the OECD and like-minded institutions, it now has a faintly negative connotation – mainstream media, mainstream tastes for instance. There are various definitions, but they all give the idea that it involves integrating biodiversity into growth and development processes and in sector policies in a systematic way (notably in agriculture, forestry and fisheries, among others).

This is going to be extremely difficult in practice, whatever the rhetoric. One of the main reasons biodiversity isn’t adequately mainstreamed is that it has to compete with other (often more visible) national priorities for growth and development, so there is insufficient political recognition of biodiversity and the underlying ecosystem services it provides. Hopefully, the new Sustainable Development Goals (SDGs) will help to change this and raise the profile of biodiversity to a higher political level. Two of the 17 SDGs focus on biodiversity (terrestrial and marine).

The way in which the political will for change comes about reminds me of one of the grim conclusions of another Insights book, on fisheries. Fishing is a good illustration of how the unsustainable exploitation of natural resources poses a problem of political economy. The impetus for change is often a major catastrophe, such as the collapse of the industry when the fish stocks suddenly disappear. However, doing what is sustainable may mean a sudden, visible, loss for a small group of people who can organise to block change, while the benefit is much more long-term, less visible and less important on an individual basis, so there is less political pressure to implement what would be the best, long-term solution overall. An OECD contribution raised a similar point at a Convention on Biological Diversity (CBD) event in Montreal earlier this month, citing “Long timeframes for mainstreaming results to occur” as one of the challenges that also arises in the context of mainstreaming biodiversity in development co-operation.

Another lesson from fisheries is that biological systems do not behave in a linear fashion. You may think a slow decline in fish numbers gives you time to find a solution, or that stocks may recover as they did sometimes in the past, but when an ecosystem reaches a tipping point, change can then become sudden and catastrophic. And usually, that tipping point is only identifiable afterwards, it can’t be forecast.

That’s why the CBD, the organisers of today’s campaign, are so worried about the interactions of a number of complex systems. Take what they say about fishing, to stick to that example. Overfishing, pollution and unsustainable coastal development are contributing to irreversible damage to habitats, ecological functions and biodiversity, going on to say that “Climate change and ocean acidification are compounding such impacts at a time when the rising global population requires more fish as food, and as coastal areas are becoming home to a growing percentage of the world’s population”.

With respected bodies like the Paleontological Research Institute at Cornell University estimating that because of human actions, current extinction rates are up to 100 times greater than they would have been otherwise, it’s getting urgent not just to act efficiently. Clunky administrative procedures in international and national programmes are a problem, as is the fact that typical projects have a 4 or 5-year cycle rather than the 10-15 years needed to make a difference. As well as that, monitoring and evaluation of mainstreaming efforts have to be more robust than at present to allow you to know what works and what doesn’t.

The SDGs’ targets for life below water and life on land are ambitious but achievable, and they’re certainly far more attractive than the alternative presented in Gilgamesh, where the Annunaki, the seven judges of hell, raise their torches, lighting the land with their livid flame. Don’t say you weren’t warned.

Useful links

The CBD, like the UN climate change convention, has a Conference of the Parties, COP. CBD’s COP 13 in Cancun, Mexico in December this year, will also be focusing on mainstreaming biodiversity as its overarching theme.

OECD work on mainstreaming biodiversity and development

Summary Record of the OECD workshop on Biodiversity and Development: Mainstreaming and Managing for Results, 18 February, 2015

Excerpts from the mainstreaming sections in ‘biodiversity’ chapters of the OECD Environmental Performance Reviews.

Biodiversity and development co-operation OECD Development Co-operation Working Papers

Economics and policies for biodiversity: OECD’s response

Behold the power of fungus… and biodiversity offsets

Korean friendship bell with Ganoderma fungus motif
Korean friendship bell with Ganoderma fungus motif

The Convention on Biological Diversity (COP 12) is taking place in Pyeongchang, Korea, until 17 October 2014. Today’s post is from Naazia Ebrahim of the OECD Environment Directorate

When you think of biodiversity conservation, you probably think of the classic images: the polar bear, the lion, the elephant, the giraffe. The ecological community likes to call them charismatic megafauna, with only a hint of satire.

But did you know that the only thing that can neutralise the deadliest, antibiotic-resistant superbug on this planet is a fungus? Now, note that it was discovered in the soil of a Canadian national park, and it rather makes the argument (well, the anthropogenic argument) for conservation of biodiversity in all its shapes and forms by itself. Behold the power of a fungus!

Unfortunately, most biodiversity has been having a rough time of it lately.

As we have all heard recently, WWF’s 2014 Living Planet Report has reported a 52% decline in mammals, birds, reptiles, amphibians and fish overall from 1970 to 2010, while IUCN’s Red List indicates that a quarter of mammals, over a tenth of birds, and 41% of amphibians are at risk of extinction. The decline is worse in the tropics, and particularly in Latin America, where species populations have dropped by 83% since 1970. Significantly scaled up efforts will be needed if we are to reach the 2011-2020 Aichi Biodiversity Targets – agreed upon at the 2010 conference of the Convention on Biological Diversity – in time. And this is true not only for conservation, but also for the sustainable use of biodiversity and natural resources.

Here at the OECD, we’re looking at how to scale up finance for biodiversity, and how instruments for conservation and sustainable use of biodiversity can be designed and implemented in more effective ways. One instrument, biodiversity offsets, has recently been gaining much attention from government and business alike. Based on the polluter pays approach, biodiversity offsets operate under a “no-net-loss” principle, and have the potential to reduce the costs of achieving environmental objectives.

To be sure, there are difficulties. The most obvious one is that biodiversity is not like carbon: one unit emitted here does not equal one unit saved there. Biodiversity is highly specific, and often highly localised; there are many ecosystems that wouldn’t necessarily exist if ecological conditions changed slightly. So project developers need to be particularly careful at building in safeguards; offsets must be a last resort after avoidance and mitigation; offset design must adhere to strict requirements for ecological equivalence; and monitoring and verification must be extremely robust.

As we work through establishing good practice insights, we hope that biodiversity offsets will be able to provide developers with an additional tool to reduce their adverse impacts on biodiversity in a cost-effective way. That really would be a win-win – and one that would make all superbug-fighting fungi happy.

Useful links

The OECD held a workshop on biodiversity offsets in November 2013, with representation from governments, industry, and civil society. Keep an eye out for our publication, forthcoming in early 2015.

Preliminary OECD Policy Highlights on Biodiversity Offsets

Chapter on Biodiversity Offsets from Scaling up Finance Mechanisms for Biodiversity

Why biodiversity matters

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Mass murderer

In 1845, Belgian farmers discovered, too late, that a load of seed potatoes they had bought from America was contaminated with Phytophthora infestans, a Mexican fungus that had recently spread northwards. The blight caused by P. infestans rapidly spread from Belgium all over the continent, triggering the European potato famine. In Ireland, 1 million people out of a population of 8 million died of starvation and its side-effects, and another million emigrated. Social, economic and political reasons help explain why the country was so badly affected, but the main cause was that a third of the population was entirely dependent on the potato for food.

The Irish famine is a stark lesson in what happens when monoculture goes wrong, and why the resilience biodiversity brings is important to agriculture. But as we celebrate International Biodiversity Day, the outlook is not very encouraging. Around 12% of birds, 25% of mammals, and at least 32% of amphibians are threatened with extinction over the next century. Humans may have increased the rate of global extinctions by up to 1000 times the “natural” rate typical of Earth’s long-term history.

Plants used for food have been hard hit. Although humans ate around 10,000 plant species in the past, today’s diet is based on just over 100 plant species, a dozen of which represent 80% of human consumption, and four of which (rice, wheat, maize and potatoes) provide more than half of our energy requirements.

China has lost 90% of the wheat varieties it had 60 years ago. The US has lost over 90% of the fruit tree and vegetable varieties it had at the start of the 20th century. Mexico has lost 80% of its corn varieties, India 90% of its rice varieties. In Spain, the number of melon varieties has gone down from nearly 400 in the early 1970s to a dozen.

Biodiversity in itself is not the key to the production, recycling and other services ecosystems provide. What matters is the abundance of the species that are critical in maintaining habitat stability and providing those services. At a local scale, the loss of a species may have an adverse impact on ecosystem services, even if that species is not threatened globally.

In OECD countries agricultural land is a major primary habitat for certain populations of wild species, particularly certain species of birds and insects, in particular butterflies. For nearly all OECD countries, agricultural land area has decreased since the 1990s. Farmland has been converted to use for forestry and urban development, with much smaller areas converted to wetlands and other land uses. While little quantitative information about the biodiversity implications of converting farmland to forestry is available, the high rates of clearance of native vegetation for agricultural use in some countries are damaging biodiversity.

Biodiversity loss can have significant economic costs, but often they are indirect and longer term, while the benefits of the action that causes the loss are more immediate and measurable. For example, clearing mangroves to make room for shrimp farms raises incomes, but mangroves are important natural coastal defences, and the new farms, and the land behind them, are then exposed to destructive flooding that climate change could make even worse.

Most ecosystem services are externalities, meaning their benefits are not bought and sold commercially. This makes it hard to use market mechanisms to protect biodiversity, and governments have to take the lead. Most OECD countries and many others have implemented conservation programmes designed to protect and enhance the populations of endangered livestock breeds, and the number of breeds included under these programmes is increasing. Greater efforts are underway to conserve plant genetic resources useful for crop improvement.

There are also some multilateral initiatives to address biodiversity issues, including the International Treaty on Plant Genetic Resources for Food and Agriculture, also known as the International Seed Treaty. This is a comprehensive international agreement in harmony with Convention on Biological Diversity, designed to guarantee food security through the conservation, exchange and sustainable use of the world’s plant genetic resources for food and agriculture, as well as the fair and equitable benefit sharing arising from its use.

Could a tragedy similar to the Irish famine happen again? Traditional threats to crop production are either acute and of relatively short duration, such as extreme weather events. Chronic threats such as desertification or urban sprawl develop slowly. Strategies for dealing with these exist or are being developed. However, a new disease affecting a major food crop (such as rice), that appeared suddenly, spread easily and resisted known treatments could pose a serious threat if it persisted over a few growing seasons. New viruses and other pathogens appear all the time spontaneously. The vast majority of them die out immediately. Occasionally though, a strain that may have been around for centuries mutates and takes advantage of present day conditions. This is probably what HIV did, and as we discussed last week, recent years have seen the sudden emergence of potentially catastrophic viruses.

Lack of alternatives to infected species and the high mobility of people and goods enabled the 19th century potato blight to spread, and both of these factors are much stronger today.

Useful links

Economics and policies for biodiversity: OECD’s response

Biodiversity Chapter of the OECD Environmental Outlook to 2050: The Consequences of Inaction “Globally, terrestrial biodiversity(measured as mean species abundance – or MSA – an indicator of the intactness of a natural ecosystem) is projected to decrease a further 10% by 2050.”

Environmental journalist Simran Sethi explains what she thinks we all can do to ensure the security and sovereignty of our seed and food:

OECD Environmental Outlook to 2050: We’re all doomed

Click to see the book on OECD iLibrary

While we were launching the OECD Environmental Outlook to 2050, a German TV crew was heading for the zoo in Limbach-Oberfrohna to film an earless rabbit, announced as the Next Big Thing after Paul the Psychic Octopus and Knut the polar bear cub. But the poor bunny turned out to be luckless too, since the cameraman stood on it and killed it. We shouldn’t try to read too much into this, but we will since it sums up so neatly the message of the latest Outlook: humans are causing serious and in some cases irreversible harm to nature.

The Scottish poet Robert Burns was prompted to think about these things when he destroyed the nest of a field mouse with his plough. The most famous part of To a mouse is when he talks about what can happen to “the best laid schemes of mice and men”. But he also regrets that “man’s dominion/Has broken Nature’s social union” justifying the ill-opinion that other creatures have of us.

One rabbit or mouse more or less may be no big deal, but the Outlook paints a depressing picture of what’s happening to life on Earth under our dominion. Terrestrial biodiversity is projected to decrease by a further 10% by 2050, with significant losses in Asia, Europe and Southern Africa. Globally, mature forest areas are projected to shrink by 13%. About one-third of global freshwater biodiversity has already been lost, and further loss is projected to 2050.

Climate change will replace agriculture as the fastest growing driver of biodiversity loss to 2050. Without a significant change in policies, global greenhouse gas (GHG) emissions are projected to increase by 50%, primarily due to a 70% growth in energy-related CO2 emissions. Global average temperature is projected to be 3C to 6C above pre-industrial levels by the end of the century, exceeding the internationally agreed goal of limiting it to 2 degrees.

The GHG mitigation actions pledged by countries in the 2010 Cancún Agreements at the UN Climate Change Conference will not be enough to prevent the global average temperature from exceeding the 2C threshold, unless very rapid and costly emission reductions are realised after 2020.

Projections like these are probably familiar to most people interested in environmental issues, but other figures in the book may prove more of a shock, notably concerning health. We may be damaging the environment, but it’s killing us. Today, unsafe water kills more people than all forms of violence, but air pollution is set to become the world’s top environmental cause of premature mortality, overtaking dirty water and lack of sanitation. The number of premature deaths from exposure to particulate matter (which leads to respiratory failures) is projected to triple from just over 1 million today to nearly 3.6 million per year in 2050, with most deaths occurring in China and India.

The absolute number of premature deaths from exposure to ground-level ozone will more than double worldwide (from 385,000 to nearly 800,000). More than 40% of the world’s ozone-linked premature deaths in 2050 are expected to occur in China and India. However, OECD countries with their ageing and urbanised populations are likely to have one of the highest rates of premature death from ground-level ozone, second only to India when the figures are adjusted for population size.

The subtitle of the Outlook is “The Consequences of Inaction”, but the authors show that actions to protect the environment make economic sense too. For instance, global carbon pricing sufficient to lower GHG emissions by nearly 70% in 2050 compared to the Baseline scenario and limit GHG concentrations to 450 ppm (the level that keeps warming below 2 degrees) would slow economic growth by only 0.2 percentage points per year on average. The potential cost of inaction on climate change could be as high as 14% of average world consumption per capita.

As the international media noted, the data and trends the report sets out are grim. But the Outlook also proposes policies, and strategies for coordinating them, across all the domains it covers. The question is whether we will take the actions required. Too often we give the impression that we’re like skydivers whose only plan is to jump from the plane and hope they’ll find a parachute somewhere on the way down.

Useful links

OECD Environment Ministerial Meeting 29 March to 30 March 2012

OECD Environment Ministers will meet in Paris under the theme of Making Green Growth Deliver. They will discuss future priorities for action based on the OECD Environmental Outlook to 2050, which makes a strong case for green growth policies.

Please feed the animals

Nature's friend

If you kill all the leopards, don’t be surprised if you get diarrhoea or worse. That’s not because of some convoluted karma (though it might be that, too) but because of the many unexpected consequences of the loss of “apex consumers” – the beasts such as large predators at the top of food chains.

In parts of sub-Saharan Africa, with the leopards (and lions) gone, baboons flourished, and came into contact with humans more frequently, attracted by crops and other food resources. Increased population density favoured the spread of intestinal parasites among the baboons to start with, then to humans.

Although ecological theory had predicted significant impacts on ecosystems from changes in the numbers and distribution of large predators and herbivores, it was hard to show this in practice. First, because the ecosystem has to be disturbed, jolted out of equilibrium, for the interactions among species to be revealed.  Also, the time scales were often too long and geographical areas too wide to be studied.

Now, a team led by James Estes of the University of California has reviewed studies of land, freshwater and marine ecosystems worldwide, and concluded that the loss of apex consumers is arguably “humankind’s most pervasive influence on the natural world”.

Estes analyses  “trophic cascades” – the idea that impacts cascade down the food chain from the apex. However, chain is too simple a metaphor to describe what happens. An ecosystem is dynamical and complex with numerous non-linear interactions and the possibility of rapid changes from one state to another, for instance when a tipping point is reached. And each ecosystem is connected to others biologically, physicochemically and spatially.

Taken together, loss of apex consumers, nonlinearity and connectivity provoke changes in just about every aspect of ecosystems and help to explain a range of phenomena, especially when you add interactions with climate change, urbanisation, and industrialised agriculture. For instance, global distribution and amounts of vegetation are poorly predicted by rainfall and temperature alone, but adding wildfires to the equation improves predictions significantly. Wildfires burn up to 500 million ha of the Earth’s surface each year, and as you’d expect are influenced by herbivores: get rid of the buffalo and more fuel is left for the fires.

Estes’ review doesn’t suggest any easy solutions. More herbivores might not give the results you’d like. Trees have now disappeared from the Scottish island of Rum, because a few hundred years ago, the last wolf was killed and with it natural control of species like deer that damaged saplings. Similar impacts are underway elsewhere, and trees aren’t the only victims of getting rid of the big good wolf. Fish can suffer too because fewer trees mean more erosion of river banks, less shade from the Sun, and less cover for the fish.

Estes and his colleagues argue for a change in ecological thinking away from the view that the influence of large animals, and apex consumers in particular, is anomalous, occurring in some systems, but not in many others. In practical terms, recognising the influence of apex consumers has profound implications for conservation. You can’t restore them on an acre of land here and there. It’s going to require a large-scale approach.

Useful links

OECD work on biodiversity management

 OECD work on green growth

White pox, dynamite, cyanide, and coral

OK coral

Coral can tell us a lot about the Earth. In his first scientific book, The Structure and Distribution of Coral Reefs, published in 1842, Charles Darwin sets out the notion that change is the natural state of our planet, an inspiration he was to pursue and refine for the next 17 years, culminating in The Origin of Species.

For Steve Jones, author of Coral: A Pessimist in Paradise, “With every breath and every death we take part in a series of transactions in which the currency of life moves through the reserves held in the soil, the skies and – most of all – the seas. Its slow revolutions made the modern world, but… it may soon break down, with disastrous consequences for the corals and for ourselves”.

In the OECD Insights Fisheries: While Stocks Last? we describe the overexploitation of  coral reefs. The million tons of fish taken from them each year is three times beyond the sustainability limit. Deep-water reefs support fish populations, but they snag nets until bottom trawlers come along and pulverise them. And when nets and traps no longer find anything, fishermen, imitating the aquarium trade, use explosives or cyanide to stun the fish and make them easy to catch.

Urbanisation and the growth of coastal populations are taking their toll as well. Wastes flushed into the sea clog the organisms and provoke coral diseases. Some of these are of human origin. White pox is caused by a bacterium usually found in the human gut and seems to survive in sewage. Herpes viruses are the main cause of coral disease, and the human herpes virus has been found in corals off Panama.

Only a third of the world’s coral reefs are healthy and a fifth have already been destroyed completely, but even without overfishing and sewage, the remainder would probably be doomed anyway. Strong sunlight plus warm water causes coral bleaching, a stress-induced reaction when the coral polyps expulse algae because the algae are photosynthesising too fast and producing too much oxygen. So as the oceans heat up, the stress will intensify, and become more permanent.

The effects of ocean acidification are worse still. The rate of calcification (building shells) is projected to be cut by half by 2100 if carbon emission trends continue unchanged, in a process that one expert has likened to osteoporosis in humans. This makes the coral reefs much more vulnerable to erosion, and they could simply wither away.

Atmospheric CO2 concentration is expected to exceed 500 parts per million and global temperatures to rise by at least 2°C by 2050-2100. This is much higher than the values under which most of today’s marine organisms evolved. The result will be less diverse reef communities and collapse of reef structures.

The World Resources institute has just published Reefs at Risk Revisited, a study on coral reefs, part of a project involving the UN World Conservation Monitoring Centre, the Global Coral Reef Monitoring Network and numerous other agencies including the International Institute for Reef Studies and NOAA.

The new report confirms the Insights description. According to the report, over 60% of the world’s reefs are under immediate and direct threat from one or more local sources such as those mentioned above.

 Overfishing — including destructive fishing — is the most pervasive immediate local threat, affecting more than 55% of the world’s reefs. Coastal development and watershed-based pollution each threaten about 25% of reefs. Marine-based pollution and damage from ships is widespread, threatening about 10% of reefs.

 Approximately 75% of the world’s coral reefs are rated as threatened when local threats are combined with thermal stress, which reflects the recent impacts of rising ocean temperatures, linked to the widespread weakening and mortality of corals due to mass coral bleaching.

There is some hope though. Reefs have shown a capacity to rebound from even extreme damage, while active management is protecting reefs and aiding recovery in some areas.

Useful links

The Biodiversity Benefits of Coral Reef Ecosystems: Values and Markets

OECD work on the environment

OECD work on fisheries