Wednesday, May 8, 2019

3238. Landmark Analysis Documents the Alarming Gobal Decline of Biodiversity

By Erik Stodstad, Science Magazine, May 6, 2019
Black rhinos, poached for their horns, are just one of some 1 million species that a new report warns are at risk of extinction. Mint Images/Aurora Photos
The state of biodiversity and ecosystems is at its most perilous point in human history and the decline is accelerating, warns a landmark assessment released today. But the hope is that the bleak assessment—crafted by hundreds of scientists and historic in its depth and breadth—will finally persuade governments and others of the need to change course and prevent further harm to the ecological systems that provide for human well-being. “What’s at stake here is a livable world,” says Robert Watson of the University of East Anglia in Norwich, U.K., who chaired the organization that produced the report.

Only transformative changes to economic, political, and social systems will allow nations to meet agreed targets for nature conservation, the authors conclude. The core message is “quite radical,” says Georgina Mace, an ecologist at University College London who reviewed the assessment. “You have to prioritize nature and nature’s benefits to people in everything you do.”

The report confirms “that we can’t just preserve, we must reverse the trend by increasing biodiversity locally, regionally, and globally,” said Alexandre Antonelli, director of the Royal Botanic Gardens, Kew in the United Kingdom, in a statement.

The report comes from the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), based in Bonn, Germany, which includes representatives from more than 100 countries. More than 450 experts from around the world were involved in drafting the 1800-page report over 3 years. They reviewed some 15,000 scientific papers and other sources of data on trends in biodiversity and its ability to provide what are known as ecosystem services or nature’s contributions to people: everything from food and fiber to clean water and air.

Many species are declining, the report notes. Out of 8 million known species of animals and plants, about 1 million are under threat of extinction, including more than 40% of amphibian species and a third of marine mammals. Even more are declining in numbers: Since 1900, native species have become, on average, about 20% less abundant. Measures of the extent and condition of natural ecosystems have declined 47% since the earliest estimates and many are deteriorating by 4% every decade.

The report highlights other metrics of the decline of nature and its human domination. They include:
  • Seventy-five percent of land has been “severely altered” by human activities.
  • More than a third of land and almost 75% of freshwater is used for crops or livestock.
  • The extent of living coral reef has dropped by perhaps half since the 1870s.
  • One hundred million hectares of tropical forest have been destroyed between 1980 and 2000.
  • Wetlands, which provide clean water and fish, are being destroyed three times faster than forests.
  • Plastic pollution has increased 10-fold since 1980 and 300 million to 400 million tons of industrial waste are dumped each year.
  • Coasts are marred by some 400 low-oxygen dead zones, equivalent to the area of the United Kingdom.
“The message is unfortunately very alarming,” says Hesiquio Benitez of the National Commission for the Knowledge and Use of Biodiversity in Mexico City, a national delegate who voted to approve the report. “We’re reaching the limits of the planet.”

For the first time at a global scale, the report has ranked the causes of damage. Topping the list, changes in land use—principally agriculture—that have destroyed habitat. Second, hunting and other kinds of exploitation. These are followed by climate change, pollution, and invasive species, which are being spread by trade and other activities. Climate change will likely overtake the other threats in the next decades, the authors note. Driving these threats are the growing human population, which has doubled since 1970 to 7.6 billion, and consumption. (Per capita of use of materials is up 15% over the past 5 decades.) The report also includes perspectives from indigenous and local communities to a greater extent than before. Lands managed by indigenous peoples are declining less quickly than elsewhere, but 72% of indicators developed by such communities show deterioration of nature.

There are a few bright spots, mostly the increasing creation of nature reserves and marine protected areas. But the progress is not nearly enough to meet most of the international conservation targets that nations set in the Convention on Biological Diversity in 2010. The declining state of nature also jeopardizes efforts to meet many of the United Nations’s Sustainable Development Goals, such as ending hunger. “If we continue with business as usual, we’ll miss [the goals],” Mace says. “We’re quite good at making plans, and quite good at setting aside protected areas, but the response of the natural world is nothing like good enough to meet the targets.”

The new report is the first global analysis of the state of nature since 2005, when researchers assembled what is known as the Millennium Ecosystem Assessment. But the hope is that the IPBES report will have a greater impact than that study. The new report “is significant, because it’s the first global assessment that has been asked for by governments—they’ve been involved in it, they’ve shaped it,” says Peter Bridgewater, a biodiversity policy expert and adjunct at the University of Canberra, who was not involved in the report. Delegates from member nations approved the report on Saturday, after a week negotiating the text of the 40-page summary for policymakers.

According to scenarios included in the report that examine the consequences of various possible policy decisions to 2050, the news will keep getting worse unless transformative change occurs. That change would involve undertaking a wide array of activities, the authors write, including land restoration, more widespread adoption of agroecological practices such as preventing soil erosion, and more widely enforced limits on fishing. Fundamentally, reversing the trends will require a shift to a more sustainable global economy, the authors state, and “steering away from the current limited paradigm of economic growth.”

In its call for transformation, the report anticipates push back: “By its very nature, transformative change can expect opposition from those with interests vested in the status quo, but such opposition can be overcome for the broader public good.” IPBES will examine how to achieve such transformative change as part of its next round of work, notes Esther Turnhout, a science policy expert at Wageningen University in the Netherlands. The goal, she says, would be to better understand “how we can tackle those challenges and why we haven’t done so.”

Anne Larigauderie, executive secretary of IPBES, is optimistic the global report released today will make a difference. “The moment for biodiversity has arrived,” she says, pointing to growing initiatives and interest in protecting nature. “There is so much evidence, and the scientific community is speaking with one voice,” Larigauderie says. “Now it’s not something that can be ignored.”

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