The United Nations has a warning: thresholds ahead.
Not only are the world’s citizens failing to halt the increasing environmental strain felt across the globe, but some of the Earth’s systems are nearing points of drastic, nonlinear change that could threaten both ecosystems and human development.
That’s the warning advanced today by a major U.N. environmental report — the fifth Global Environmental Outlook (GEO-5) — prepared in advance of the U.N. Conference on Sustainable Development this month in Rio de Janeiro, known as Rio+20, which will bring a host of world leaders together to discuss the balance between growth and environmental degradation.
“If current patterns of production and consumption of natural resources prevail and cannot be reversed and ‘decoupled,’ then governments will preside over unprecedented levels of damage and degradation,” said Achim Steiner, executive director of the U.N. Environment Programme, in launching the report.
With the report, the United Nations has reaffirmed its use of a controversial new metric for assessing the world’s sustainable path: “planetary boundaries.” Proposed three years ago in the journal Nature, the boundaries are roughly based on the limits estimated during the past 10,000 years of human activity, and they have been seized upon by policymakers seeking a guide to the future of life on Earth.
The endorsement of world leaders for such boundaries — say, for example, a limit for atmospheric carbon dioxide, land-use change or biodiversity loss — is expected to be a major rhetorical highlight of the Rio+20 summit. And unlike its predecessor two decades ago, which resulted in the U.N. Framework Convention on Climate Change and the Convention on Biological Diversity, Rio+20 is unlikely to score any international binding agreements, making the battle over its message especially important.