Global Warming Kills Species, Endangers Humans

Global Warming Kills Species, Endangers Humans - Scientists

Stephen Leahy

BROOKLIN, Canada, May 18 (IPS) - Global warming may now be the largest cause of soaring rates of species extinctions, which threaten the global ecosystems that sustain life on Earth, scientists say.

The rapidly warming polar regions are a prime example, said Jeffrey McNeely, chief scientist for IUCN-the World Conservation Union (IUCN). The melting ice and permafrost are changing the habitat Arctic species need to survive, Mc Neely told IPS in advance of International Day for Biological Diversity, which falls on May 22.

''Climate change will simply accelerate habitat loss which already is the leading threat to species,'' McNeely said from his office in Gland, Switzerland.

The diversity of life on the planet is in steep decline due to habitat destruction, invasion by non-native species and over-exploitation by humans, and now climate change is the latest and perhaps greatest threat according to David King, the British government's chief scientific adviser.

''The warming could take place so quickly that many species will not be able to adapt quickly enough,'' King wrote in the British journal Birds earlier this month.

The current rate of species loss is estimated to be 1,000 times faster than at any time in history. With the expected changes due to climate change, up to 30 percent of all mammal, bird, and amphibian species are in danger of disappearing by 2050, according to a recent report from the Millennium Ecosystem Assessment.

The assessment is an unprecedented 22-million-dollar study of Earth's life support systems. Since 2001, some 1,350 experts from 95 countries have compiled and analysed all available data on 24 of the planet's vital ecosystems and concluded that 15 are being degraded or used in an unsustainable fashion.

In essence, the assessment finds that life on Earth is unraveling.

The major difference between the lifeless, barren Moon that orbits Earth is the thin skin of life that covers the latter. Biological diversity refers to the amazing variety of living things that make up that skin, which scientists call the biosphere. Between 10 and 100 million multi-celled species make up the biosphere although only 1.5 million have been identified so far.

With so many species, the loss of a few dozen or even hundreds of exotic creatures like the Dodo or Tasmanian Tiger, while lamentable, could scarcely be considered the critical issue of the 21st century.

Yet, that is what the millennium assessment says. Ecosystems that support all life are being degraded because of the loss of biodiversity.

''The living machinery of the Earth has a tendency to move from gradual to catastrophic change with little warning,'' states the study.

Of course some species are more important than others. An ecosystem is like a house of cards: removing some cards -- or in this case, species -- makes the structure weaker but it remains standing. But remove one or two others, and it collapses.

''Everything is connected to everything else,'' said Rod Mast, vice president of the U.S.-based environmental group Conservation International. This interconnectedness is the fundamental principle of ecology.

''Sea turtles are a keystone species. They help keep coral reefs and beds of sea grass healthy,'' Mast said in an interview. ''Their eggs are important food sources for shoreline birds and mammals.''

The extinction of the endangered Leatherback or Kemp's Ridley sea turtles could have wide-ranging and largely unknown impacts on the ocean ecosystem, he said. In fact the status of sea turtles worldwide remains unknown. Mast said he hopes the first global assessment will be completed this year.

Much more is known about forest ecosystems but the full range of services they provide the planet is under appreciated. For example, forests produce oxygen, clean water, prevent erosion and flooding, capture excess carbon dioxide, and provide food and habitat for many species.

Logging all the trees in a forest ends up eliminating many species of plants, animals, birds, and insects. It also results in a loss of those ecosystem services for many years, and in some cases permanently because reduced biodiversity makes it difficult for the forest to recover.

British researchers confirmed this in a study published in the journal Nature last April. The greater the diversity of species on an island, the higher the proportion of endemic species on that island they found. In other words, biodiversity begets biodiversity.

However, more than 15,500 species now face extinction and another 60,000 are threatened, according to IUCN's 2004 Red List of Threatened Species.

By 2050, the world will be a very different place, said Stuart Pimm, a leading conservation biologist at Duke University in the U.S. state of North Carolina.

''Vast areas of the tropics that have lost their forests will have the same damn weeds, bushes and scrawny eucalyptus trees so that you don't know if you're in Africa or the Americas,'' Pimm said.

''Without its natural diversity the world will be a poorer place. It will be boring,'' he added.

Perhaps more important will be the loss of services that the natural world currently provides free of charge.

''Nearby forests provide the clean, untreated drinking water of two the world's great cities, New York City and Rio de Janeiro,'' Pimm said.

Pricing and paying for nature's ''free'' services like soil formation, pollination, and water cleaning is difficult but a crucial step in reducing ''our profligate consumption'' added IUCN's McNeely.

World consumption of natural resources has increased by a factor of 16 while the global population has only increased by a factor of four since 1900, McNeely said.

''Many of us are convinced that this rate of consumption is not sustainable,'' he added.

In addition to significant reductions in consumption is the need for greater equity considering that ''over one billion people are officially listed as obese, while 800 million are under nourished,'' said Pimm. He suggested using economic tools such as higher taxes on the wealthy and financial incentives to support conservation of biodiversity.

''We have to stop doing stupid things like subsidising economically and ecologically damaging activities,'' said Pimm.

''For example the global fish catch is worth about 50 billion dollars at the dock but government subsidies to the fishing industry amount to 100 billion dollars.''

Tax subsidies are also behind much of the clear-cut logging that goes on in the Amazon rainforest and in many other forests, Pimm said.

Over-exploitation of the local environment has led to the extinction of a number of cultures, said McNeely.

''Although descended from cultures that managed their resources sustainably, it does not appear that we have learned the lessons from our ancestors very well,'' he said. (END/2005)