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Biodiversity: Life ­– a status report
Species are disappearing quickly — but researchers are struggling to assess how bad the problem is.

Richard Monastersky
10 December 2014 Corrected: 18 December 2014

予測される最速のスピードで種がなくなっていくと、2200年にはsixth mass extinctionが起きてしまようです。

March towards mass extinction
Mass extinctions — loss of 75% of existing species — have happened 5 times in the planet’s history. If there are 5 million animal species and they are disappearing at rate of 0.72% per year (the upper end of estimates), a sixth mass extinction could happen by the year 2200. At the low end of the estimated range, a mass extinction would not happen for thousands of years.

11月にWorld Parks Congressという国際会議が開かれたのに合わせて、先月は自然保護について特集を組んでいたようです。

As conservation scientists and practitioners converge on Sydney for the once-in-a-decade World Parks Congress, a Nature collection of news, comment, reviews and research explores priorities for protecting the planet.


Economics: Account for depreciation of natural capital
Edward B. Barbier
05 November 2014
Economic indicators that omit the depletion and degradation of natural resources and ecosystems are misleading, warns Edward B. Barbier.

For the past year, academics and policy-makers have been discussing Thomas Piketty's 2013 economics best-seller, Capital in the Twenty-First Century1. It documents the considerable rise over the past 40 years in national wealth relative to national income in eight of the richest economies — the United States, Japan, Germany, France, the United Kingdom, Italy, Canada and Australia. The national wealth of each of these countries increased from 2–3 times national income in 1970 to 4–6 times income in 2010.

Piketty relies on standard income conventions as prescribed in the United Nations national accounts. He includes natural resources such as fossil fuels, minerals and forests in his estimate of a country's capital. But his measures of national income and savings adjust only for depreciation of 'fixed capital' — buildings, equipment and so on.

We must also account for the depreciation of natural capital in appraising wealth. This is the value of net losses to natural resources, such as minerals, fossil fuels, forests and similar sources of material and energy inputs into our economy. If we use up more natural capital to produce economic output today, then we have less for production tomorrow.

自然の資本を計算してみたときに二つの傾向が顕著のようです。Two global trends are noticeable. First,…Second,…なんて書き方は参考にできます。

Two global trends are noticeable. First, the decline in natural capital has been five times greater on average in developing economies than in the eight richest countries. Second, natural capital depreciation in all countries has risen significantly since the 1990s. There was a dip during the global recession of 2008–09, but as the world economy has recovered, so has the rate of resource use.
Ecological capital, too, is clearly endangered by current patterns of economic development. Over the past 50 years, ecosystems have been modified more rapidly and extensively than in any comparable period in human history, largely to meet burgeoning demands for food, fresh water, timber, fibre and fuel. According to the worldwide Millennium Ecosystem Assessment, approximately 60% of major global ecosystem services have been degraded or used unsustainably, including fresh water, wild fisheries, air and water purification, and the regulation of regional and local climate, natural hazards and pests.


Unfortunately, ecological capital, being unique, poorly understood and difficult to measure, tends to be undervalued. Consider the example of mangroves in Thailand from 1970 to 20092. Average annual mangrove loss in Thailand has fallen steadily in every decade since the 1970s. Yet cumulatively, Thailand is estimated to have lost around one-third of its mangroves since the 1970s, mainly to the expansion of shrimp farming and other coastal development.