Planetary boundaries

During the recent years, the term sustainability has been used quite broadly. As a biologist, I seldom think of the role of people within a society. My definition of sustainability is, therefore, linked to resilience of a group. This group may refer to a population, a single species, a community, a region, and others. But before, I would like to focus on something else (still related to this subject).

According to the Stockholm Resilience Centre (SRC), there are nine planetary boundaries. These refer to border definitions of natural ecosystems, including humans (yes, we are supposedly a part of nature too). For the sake of misunderstandings, I decided to summarized them in a single sentence each, so I can refer to them in the future. I give really short descriptions, with a non-scientific language, just to keep it simple. I apologize to scientists who read this.

1) Stratospheric ozone layer - Filters out ultraviolet radiation from the sun that could otherwise increase incidence of skin cancer in humans, and damage terrestrial and marine biological systems.

2) Biodiversity - Number of species within a specific region that, when reaches 0 (zero in that specific region) for a specific species, this species is then extinct in that region.
3) Chemicals dispersion - Emissions of persistent toxic compounds that may reduce fertility and permanent genetic damage.
4) Climate Change – Alterations in temperature, humidity, atmospheric pressure, wind, precipitation, among many others, that have diverse effects within the Earth system.

5) Ocean acidification – The oceans absorb around a quarter of the CO2 produced, rising its acidity, and reducing carbonate ions, which is essential for shell and skeleton formation in organisms such as corals, and some shellfish and plankton species.
6) Freshwater consumption and the global hydrological cycle - This cycle, as a key to keep the planet within the climate boundary, is, however, strongly affected by climate change, and is dramatically decreased by human consumption.
7) Land system change – The transformation of forests, wetlands, and other vegetation types in agricultural land reduces biodiversity, affects water flows, and biogeochemical cycles (such as the one of carbon).
8) Nitrogen and phosphorus inputs to the biosphere and oceans - Human activities convert huge amounts of N2 from the atmosphere into reactive forms, which pollute waterways and coastal zones, are emitted back to the atmosphere in various forms, or accumulate in the terrestrial biosphere.
9) Atmospheric aerosol loading - Without aerosol particles in the atmosphere, we would not have clouds, by reflecting incoming sunlight back to space, which may keep the planet at “living temperatures”.

I hope it is understandable now.

Rockström, J., W. Steffen, K. Noone, Å. Persson, F. S. Chapin, III, E. Lambin, T. M. Lenton, M. Scheffer, C. Folke, H. Schellnhuber, B. Nykvist, C. A. De Wit, T. Hughes, S. van der Leeuw, H. Rodhe, S. Sörlin, P. K. Snyder, R. Costanza, U. Svedin, M. Falkenmark, L. Karlberg, R. W. Corell, V. J. Fabry, J. Hansen, B. Walker, D. Liverman, K. Richardson, P. Crutzen, and J. Foley. 2009. Planetary boundaries:exploring the safe operating space for humanity. Ecology and Society 14(2): 32. PDF

I did it! Ok, not everything, but I am trying. I have achieved quite a lot for such a short time.

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