Don't fence me in, but then again once the horse is out of the barn...

The Economist has an article on the quantification of certain environmental factors where our ecosystem should be bounded for us to be part of that ecosystem. Scientists are getting confident enough to even set some numbers.

The nine areas of concern were: climate change; ocean acidification; the thinning of the ozone layer; intervention in the nitrogen and phosphate cycles (crucial to plant growth); the conversion of wilderness to farms and cities; extinctions; the build up of chemical pollutants; and the level of particulate pollutants in the atmosphere. For seven of these areas the paper's authors felt confident enough to put numbers on where the boundaries actually lay. For chemicals and particulates, they deferred judgment.

The article covers some of the criticisms and some of the impacts of ignoring the possibility of limits. The question for me is always reversibility, once we reach a point of no return why would we tempt it. Nature finds a way to move on, I don't believe that time will stop once we leave the planet so the question is never "save the earth" but "save our grandchilren's children"