Janet Larsen
Janet LARSEN is the Director of Research at the Earth Policy Institute (a non-profit environmental research organisation) and holds a degree in Earth Systems from Stanford University. Formerly a researcher at the Worldwatch Institute, she is also currently a contributor to Vital Signs (the Worldwatch Institute’s annual publication) and The Earth Policy Reader (distributed by the Earth Policy Institute), in domains such as land use, population, biodiversity, natural resource management, and agriculture. She has also studied the rainforest and the amphibians of the Amazon (Peru).
The Food and Agriculture Organization of the United Nations (FAO) is a specialized agency of the United Nations. It was founded on 16 October 1945 in Quebec City, Quebec, Canada. In 1951 its...
Peter Singer is Professor of Bioethics at Princeton University and Laureate Professor at the University of Melbourne. His books include Practical Ethics, One World, and, most recently, The Life You...
Arnaud Gossement is a lawyer at the Paris Bar for environmental law and energy. He has a PhD in Law from Paris I University Panthéon-Sorbonne and he is a lecturer at Sciences Po Paris. He has also...
Achim Steiner est le directeur exécutif du Programme des Nations Unies pour l'Environnement (PNUE). Auparavant, il a exercé de hautes fonctions à la Commission mondiale des barrages puis à l'Union...
Antoine F. Goetschel is a laywer who specializes in animal rights.
Alistair Gammell is director of the Chagos campaign, a project of the Pew Environment Group’s Global Ocean Legacy initiative to help secure the establishment of large, world-class marine reserves. ...
Dr. Ahmed Djoghlaf is the Executive Secretary of the Convention on Biological Diversity established by the United Nations. An Algerian national, Dr. Djoghlaf has pursued a impressive diplomatic...
George Monbiot is a well-known investigation reporter and columnist for the British newspaper “The Guardian” as well as a member of the BBC Wildlife magazine’s advisory board. He is also the author...
Susan Lieberman is Deputy Director of The Pew Environment Group and head of the Cites Pew Delegation at the CITES summit in Doha.
Julia Marton-Lefèvre is the Director General of International Union for Conservation of Nature (IUCN).Photo: IUCN
Fred Pearce is journalist specialized in the environment and development. He was born in the United Kingdom and studied geography in the University of Cambridge. His latest book is When the Rivers...
Carl Zimmer travaille comme journaliste spécialiste des questions scientifiques et environnementales. Il a rédigé 6 livres et s’intéresse à des domaines aussi variés que la recherche dans les...
Silvia Ribeiro et Kathy Jo Wetter travaillent toutes deux en tant que chercheuses pour l'Action Group on Erosion, Technology and Concentration (ETC Group).
New Scientist was founded in 1956, this internationally-focused weekly British magazine aims at giving readers exhaustive information on recent worldwide developments in science from a scientific,...
Brendan Moyle is a conservationist from New Zealand. Long ago, he used to study tiny pseudoscorpions as a zoologist. He got a PhD in economics because it was rather obvious that a lot of conservation...
New Scientist was founded in 1956, this internationally-focused weekly British magazine aims at giving readers exhaustive information on recent worldwide developments in science from a scientific,...
IUCN : Created in 1948, the World Conservation Union or International Union for the Conservation ofr Nature (IUCN) brings together 81 States, 120 government agencies, 800 plus NGOs, and some 10,000...
Jean-Michel SEVERINO has been CEO of France’s international development agency (AFD) since 2001. After graduating from the Ecole Nationale d’Administration and the Institut d’Etudes Politiques de...
The Ramsar Convention is an international treaty for the conservation and sustainable use of wetlands, aiming to stop their degradation and disappearance, today and tomorrow, by recognizing their...
François RAMADE, an agricultural engineer who holds a doctoral post-graduate degree in science, is a professor emeritus at the Université Paris-Sud (Orsay). He is a former President of the Société...
New Scientist was founded in 1956, this internationally-focused weekly British magazine aims at giving readers exhaustive information on recent worldwide developments in science from a scientific,...
Solenn Honorine holds degrees from Sciences Po (Bordeaux), the University of California, Los Angeles (UCLA), and the Ecole Supérieure de Journalisme in Lille. Ms. Honorine is a French freelance...
Janet LARSEN is the Director of Research at the Earth Policy Institute (a non-profit environmental research organisation) and holds a degree in Earth Systems from Stanford University. Formerly a...
The sixth great extinction: A Status Report
31/08/2008 2:53 pm
Almost 440 million years ago, some 85 percent of marine animal species were wiped out in the earth's first known mass extinction. Roughly 367 million years ago, once again many species of fish and 70 percent of marine invertebrates perished in a major extinction. Then about 245 million years ago, up to 95 percent of all animals—nearly the entire animal kingdom—were lost in what is thought to be the worst extinction in history.
Some 208 million years ago, another mass extinction took a toll primarily on sea creatures, but also some land animals. And 65 million years ago, three quarters of all species—including the dinosaurs—were eliminated.
Among the possible causes of these mass extinctions are volcanic eruptions, meteorites colliding with the earth, and a changing climate. After each extinction, it took upwards of 10 million years for biological richness to recover. Yet once a species is gone, it is gone forever.
The consensus among biologists is that we now are moving toward another mass extinction that could rival the size of the 5 previous ones. This potential sixth great extinction is unique in that it would be caused largely by the activities of a single species. It would be the first mass extinction that humans would witness firsthand—and not just as innocent bystanders.
While scientists are not sure how many species inhabit the planet today, their estimates top 10 million. Yet each year thousands of species, ranging from the smallest micro-organisms to larger mammals, are lost for good. Some disappear even before we know of their existence.
The average extinction rate is now some 1,000 to 10,000 times faster than the rate that prevailed over the past 60 million years. Throughout most of geological history, new species evolved faster than existing species disappeared, thus continuously increasing the planet's biological diversity. Now evolution is falling behind.
[...]
Today nearly 5,500 animal species are known to be threatened with extinction. The IUCN—World Conservation Union's 2003 Red List survey of the world's flora and fauna shows that almost one in every four mammal species and one in eight bird species are threatened with extinction within the next several decades. (For access to IUCN's Red List of Threatened Species database, see www.redlist.org).
Of 1,130 threatened mammal species, 16 percent are critically endangered—the highest threat level. This means that 184 mammal species have suffered extreme and rapid reduction in population or habitat and may not survive this decade. Their remaining numbers range from under a few hundred to, at most, a few thousand individuals. For birds, 182 of the 1,194 threatened species are critically endangered.
Although the status of most of the world's mammals and birds is fairly well documented, we know relatively little about the rest of the world's fauna. Only 5 percent of fish, 6 percent of reptiles, and 7 percent of amphibians have been evaluated. Of those studied, at least 750 fish species, 290 reptiles, and 150 amphibians are at risk. Worrisome signs—like the mysterious disappearance of entire amphibian populations and fishers' nets that come up empty more frequently—reveal that there may be more species in trouble. Of invertebrates, including insects, mollusks, and crustaceans, we know the least. But what is known is far from reassuring.
At the advent of agriculture some 11,000 years ago, the world was home to 6 million people. Since then our ranks have grown a thousandfold. Yet the increase in our numbers has come at the expense of many other species.
The greatest threat to the world's living creatures is the degradation and destruction of habitat, affecting 9 out of 10 threatened species. Humans have transformed nearly half of the planet's ice-free land areas, with serious effects on the rest of nature. We have made agricultural fields out of prairies and forests. We have dammed rivers and drained wetlands. We have paved over soil to build cities and roads.
Each year the earth's forest cover shrinks by 16 million hectares (40 million acres), with most of the loss occurring in tropical forests, where levels of biodiversity are high. Ecologically rich wetlands have been cut in half over the past century. Other freshwater and terrestrial ecosystems have been degraded by pollution. Deserts have expanded to overtake previously vegetated areas, accelerated in some cases by overgrazing of domesticated animals.
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Direct human exploitation of organisms, such as through hunting and harvesting, threatens more than a third of the listed birds and mammals. Other threats to biodiversity include exotic species, often transported by humans, which can outcompete and displace native species.
A recent survey of some 1,100 animal and plant species found that climate change could wipe out between 15 and 37 percent of them by 2050. Yet the actual losses may be greater because of the complexity of natural systems. The extinction of key species could have cascading effects throughout the food web. As John Donne wrote, "no man is an island." The same is true for the other species we share this planet with: the loss of any single species from the web of life can affect many others.
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The 1992 Convention on Biological Diversity provides a framework for countries to conserve biological diversity and promote sustainable development. It has been signed by 168 countries, notably excluding the United States. The parties, which recently held their seventh conference in February 2004 in Kuala Lumpur, have set a target of substantially reducing biodiversity loss by 2010. Yet the convention lacks mechanisms for action and enforcement, which may make it difficult to achieve the target.
Consciously avoiding habitat destruction and mitigating the effects of land use change, reducing the direct exploitation of plants and wildlife, and slowing climate change can help us stop weakening the very life-support systems we depend on. While this may be the first time in history that a single species can precipitate a mass extinction event, it is also the first time in history that a single species can act to prevent it.
TJanet Larsen
Earth Policy Institute
02/03/2004
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