April 02, 2012
‘Numerous Drawbacks’ for ‘Planetary Boundaries’ Hypothesis: The Economist
The Breakthrough Institute has stirred international debate over the controversial "planetary boundaries" hypothesis, which has been proposed for adoption at this month's United Nations Earth Summit in Brazil. Citing a new Breakthrough Institute report released this week, The Economist writes that the concept of planetary boundaries has "numerous drawbacks":
The actual location of the boundaries is, as their proponents acknowledge, somewhat arbitrary. That is partly because of the incomplete state of current knowledge, but it may remain so however much anyone knows. Some boundaries might be transgressed without irreversible harm occurring. Some may have been drawn around the wrong things altogether. And some academic opinion holds that spectacular global change could come about without breaking through any of them.
The latest criticism comes from the Breakthrough Institute, a determinedly heterodox American think-tank that focuses on energy and the environment. Among the points made in a report it published on June 11th, two stand out. The first is that the idea of boundaries does not focus enough on the distinction between things with truly global effects and those that matter primarily at a local or regional level. The second is that the planetary-boundaries group derives most of its limits by looking at conditions during the Holocene -- the epoch since the end of the most recent ice age, in which human civilizations have grown up. Both of these criticisms have merit.
The planetary boundaries hypothesis, first introduced by a group of leading earth scientists in a 2009 article in Nature, posits that there are nine global, biophysical limits to human welfare: climate change, ocean acidification, the ozone layer, nitrogen and phosphate levels, land use change (the conversion of wilderness to human landscapes like farmland or cities), biodiversity loss, chemical pollutants, and particulate pollution in the atmosphere. The concept has been endorsed by UN bodies and leading environmental organizations like Oxfam and the World Wildlife Fund for Nature.
After an extensive review of the scientific evidence, however, the Breakthrough Institute found the "planetary boundaries" framework to be a misleading guide that masks inherently political trade-offs in the management of complex environmental challenges.
As the authors of the concept admit, six of the nine proposed "planetary boundaries" have no global limits at all. Only three -- climate change, ocean acidity, and ozone levels -- have identifiable global thresholds.
While the other six elements have important local or regional impacts, adopting policies based on global limits could be misguided. People in some areas, for example, must increase their use of freshwater or nitrogen (in the form of fertilizer) to improve welfare. Those in others should reduce such use to avoid droughts or "dead zones" caused by excessive levels of nitrogen.
The Economist also highlighted the implicit assumption made by the "planetary boundaries" authors that the conditions of the Holocene are preferable to those humanity faces now. While there is good reason to believe that the relatively warm and stable climate of the Holocene has been of critical importance to human development, there is little evidence that it would be better for humanity if other proposed boundaries -- especially land use change, levels of nitrogen and phosphorous, or biodiversity -- return to Holocene levels.
The Economist writes:
This is, at bottom, an argument about the nature of the Anthropocene -- the age of man. Many scientists feel that human interference in the way the Earth works is now so great that the Holocene is history and a truly separate Anthropocene has dawned. The planetary-boundaries idea seeks to constrain the Anthropocene within the norms of the Holocene. The Breakthrough Institute, by contrast, argues for ordering things according to a calculation of the needs of human welfare, rather than just aping what has happened in the past. There is no doubt as to which of the two approaches is more prudent, and prudence always has a constituency. There is plenty of room for debate as to which is more plausible, or practical.
Let the debate begin.
Additional coverage: The Breakthrough Institute report was also featured this week in a series of posts by journalist Keith Kloor and in an article in Scientific American by David Biello.
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