| Global Scope. Problems of sustainabloe scale are unprecedented in the history of human civilization (Ponting,1991;McNeil, 2000). Previous environmental problems were local or regional. Human activities are now affecting several global ecosystems that co-evolved over millions of years, that provided the conditions for life to evolve on the planet, and that are essential for our continued survival. The very fact that our activities are affecting such robust and essential life support services should be a major cause for concern (see Areas of Concern). |
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