Word: earths
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Dates: during 2000-2009
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...scientific name is the Holocene Age, but climatologists like to call our current climatic phase the Long Summer. The history of Earth's climate has rarely been smooth. From the moment life began on the planet billions of years ago, the climate has swung drastically and often abruptly from one state to another - from tropical swamp to frozen ice age. Over the past 10,000 years, however, the climate has remained remarkably stable by historical standards: not too warm and not too cold, or Goldilocks weather. That stability has allowed Homo sapiens, numbering perhaps just a few million...
...human population has exploded over the past few thousand years, the delicate ecological balance that kept the Long Summer going has become threatened. The rise of industrialized agriculture has thrown off Earth's natural nitrogen and phosphorus cycles, leading to pollution on land and water, while our fossil-fuel addiction has moved billions of tons of carbon from the land into the atmosphere, heating the climate ever more. (See the top 10 green ideas...
...Sept. 24 issue of Nature says the safe climatic limits in which humanity has blossomed are more vulnerable than ever and that unless we recognize our planetary boundaries and stay within them, we risk total catastrophe. "Human activities have reached a level that could damage the systems that keep Earth in the desirable Holocene state," writes Johan Rockstrom, executive director of the Stockholm Environmental Institute and the author of the article. "The result could be irreversible and, in some cases, abrupt environmental change, leading to a state less conducive to human development." (See TIME's special report on the environment...
...prove hard to stop unless we reduce emissions sharply. Ditto for the nitrogen cycle, where industrialized agriculture already has humanity pouring more chemicals into the land and oceans than the planet can process, and for wildlife loss, where we risk biological collapse. "We can say with some confidence that Earth cannot sustain the current rate of loss without significant erosion of ecosystem resilience," says Rockstrom...
...levels. And by setting a boundary, it might make policymakers believe that we can pollute up to that limit and still be safe. That's not the case - pollution causes cumulative damage, even below the tipping point. By focusing too much on the upper limits, we still risk harming Earth. "Ongoing changes in global chemistry should alarm us about threats to the persistence of life on Earth, whether or not we cross a catastrophic threshold any time soon," writes William Schlesinger, president of the Cary Institute of Ecosystem Studies, in a commentary accompanying the Nature paper...