Backward and Forward: Planetary Limits

In looking backward, yesterday, theÊOrganic Consumers AssociationÊgave special thanks to the indigenous farmers and wildcrafters of the Western Hemisphere for cultivating and preserving our food, fiber, medicinal herbs, and biodiversity for thousands of years. Ê

Today was officially Native American Heritage Day, as declared in June 2009 decree by the Obama Adminstration.

And in looking foward,ÊNASA has identified nine planetary boundariesÊwith. . . quantifications for seven of them:

- Êclimate change: CO2 concentration in the atmosphere <350 ppm and/or a maximum change of +1 W/m2 in radiative forcing;Ê

- ocean acidification - mean surface seawater saturation state with respect to aragonite ³ 80% of pre-industrial levels;Ê

- <5% reduction in statosphere ozone concentration from pre-industrial level of 290 Dobson UnitsÊ

- limit industrial and agricultural fixation of N2 to 35 Tg N/yrÊand annual P inflow to oceans not to exceed 10 times the natural background weathering of P;Ê

- global freshwater use (<4000 km3/yr of consumptive use of runoff resources);Ê

- land system change (<15% of the ice-free land surface under cropland); andÊ

- the rate at which biological diversity is lost (annual rate of <10 extinctions per million species)."Ê

http://pubs.giss.nasa.gov/cgi-bin/abstract.cgi?id=ro06010m

Our collective work is to keep within these limits, to honor indigenous farming, wildcrafting, and biodiversity into the future.

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