Global biological diversity in decline
Rhett A. Butler, mongabay.com
March 20, 2006
Global biological diversity is increasingly threatened according to a report released by at the outset of the largest biodiversity conference in more than a decade. More than 3000 delegates and 100 government ministers have gathered in Curitiba, Brazil at the eighth Convention on Biological Diversity to discuss the outlook for Earth’s species.
The report, Global Biodiversity Outlook 2, says that we are currently in the midst of the worst extinction event since the disappearance of the dinosaurs and that this species loss is entirely the result of human activities.
“In effect, we are currently responsible for the sixth major extinction event in the history of the Earth, and the greatest since the dinosaurs disappeared, 65 million years ago,” the report states.
Ongoing destruction of wilderness areas is cited as the leading cause of declining global biodiversity, but climate change could have an increasingly important impact, especially in ecosystems of the Arctic and Antarctic where glaciers and sea ice are fast-disappearing.
Photo by R. Butler
The UN describes biodiversity as “the combination of life forms and their interactions with one another, and with the physical environment that has made Earth habitable for humans.”
The report says that biodiversity loss is disrupting ecosystem functions, making ecosystems more vulnerable to shocks and disturbances, and less able to supply humans with ecological services like soil protection, carbon sequestration, flood control and water filtering. The report notes that “consequences of biodiversity loss and ecosystem disruption are often harshest for the rural poor, who depend most immediately upon local ecosystem services for their livelihoods and who are often the least able to access or afford substitutes when these become degraded.”
The report estimates that global demand for resources now exceeds the biological capacity of the Earth by some 20 percent, while wild species abundance fell by about 40% between 1970 and 2000.
Other notes from the report
Since 2000, 6 million hectares of primary forest have been lost annually.
In the Caribbean, average hard coral cover declined from 50% to 10% in the last three decades. 35% of mangroves have been lost since 1980.
Protected areas cover some 13% of the world’s land area, but these are unevenly distributed and some are not effectively managed.
The average abundance of species is declining — 40% loss between 1970 and 2000. Species present in rivers, lakes and marshlands have declined by 50%. Declines are evident in amphibians, African mammals, birds in agricultural lands, corals and commonly harvested fish species.