The debate about global environmental decline has been dominated by the wide-ranging harm expected from future climate change. Far less discussed, but equally dangerous, is the accelerating decline of the natural world. The over-exploitation of soils and seas, the cutting of forests and the pollution of air and water are together devastating the living world, according to a massive new UN-sponsored report from the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). The full, 1,500-page report will be published later in 2019 but this summary for policy makers has just been released. The four sections of the summary cover the decline in biodiversity and ecosystem services, the accelerating drivers of this change, the failure to meet many of the goals set for conservation and the very challenging actions needed to restore sustainability. The report's most alarming findings have been widely reported. Of an estimated 8 million animal and plant species (75 percent of which are insects), around 1 million are threatened with extinction—more than ever before in human history. Over 40 percent of amphibian species, almost 33 percent of corals, and more than a third of all marine mammals are threatened. At least 680 vertebrate species have been driven to extinction. All this is largely the result of human actions. Three-quarters of the land-based environment and about 66 percent of the marine environment have been significantly altered by man. More than a third of the world's land surface and nearly 75 percent of freshwater resources are now devoted to crop or livestock production. A third of marine fish stocks are being harvested at unsustainable levels. In sum, the biosphere is being altered at an unprecedented scale and pace. The dominant driver of these adverse trends is humanity's rapidly growing need for food, energy, water, and materials. The value of agricultural crops has increased by 300 percent since 1970, raw timber harvest has risen by 45 percent and approximately 60 billion tons of renewable and nonrenewable resources are now extracted globally every year—twice the level estimated for 1980. Land degradation has reduced the productivity of 23 percent of the global land surface. Climate change will accelerate many of these adverse effects over coming decades. The summary concludes with an enumeration of dozens of actions that can be taken by governments, researchers, and individuals, such as practicing informed government, improving documentation of nature, promoting sustainable agricultural practices, and reducing food waste. The report is authoritative and rich in scientific content based on meticulous research conducted by hundreds of scientists. But the text is also densely written, and its major sections consist largely of dozens of separate numbered paragraphs with only a weak overall story line. Readers of PDR may well be disappointed that the role population growth (which is clearly one of the most important indirect drivers of the loss of nature) is barely mentioned and the long list of proposed remedial actions does not mention population policies at all.
更多
原文链接
分享
引用
