Nature paper on global ecological "state shift"

[Ken Caldeira]

http://www.nature.com/nature/journal/v486/n7401/full/nature11018.html

Folks,

If we consider "geoengineering" broadly, as intentionally intervening in natural processes at a global scale, we have done this extensively already through our use of land and sea.

As a result of human activities, direct local-scale forcings have accumulated

to the extent that indirect, global-scale forcings of biological

change have now emerged. Direct forcing includes the conversion of

~43% of Earth’s land to agricultural or urban landscapes, with much of

the remaining natural landscapes networked with roads (1,2,34,35). This

exceeds the physical transformation that occurred at the last global-scale

critical transition, when ~30% of Earth’s surface went from being

covered by glacial ice to being ice free.

...  An inordinate amount of energy now is routed through

one species, Homo sapiens. Humans commandeer,20–40% of global net

primary productivity1,2,35 (NPP) and decrease overall NPP through habitat

degradation.

Again, I am sure that one could develop various metrics for physical transformations of Earth's (land?) surface, and for some of them the amount of change would exceed that experienced in glacial-interglacial transitions, and for others not. However, such quibbling does not dispute the central point that we have become a global force acting on Earth's biosphere.

It is not clear to me that the language of "state shift"adds much to this review of threats to (mostly) land ecosystems. However, whether you think it is a "state shift" or not, we surely are impacting Earth's biota on a grand scale.

Best,

Ken

_______________
Ken Caldeira

Carnegie Institution for Science 

Dept of Global Ecology

260 Panama Street, Stanford, CA 94305 USA

+1 650 704 7212 kcal...@carnegiescience.edu

http://dge.stanford.edu/labs/caldeiralab  @kencaldeira

Currently visiting  Institute for Advanced Sustainability Studies (IASS)  

and Potsdam Institute for Climate Impact Resarch (PIK) in Potsdam, Germany.

[Russell Seitz]

In March 2009 , I noted in<i>Foreign Affairs</i> 

http://www.foreignaffairs.com/articles/65159/russell-seitz/the-next-top-model  that

Geoengineering ... has been an integral part of the landscape of history. Although Benjamin Franklin wrote in 1751,

 

"We are, as I may call it, scouring our planet, by clearing America of woods, and so making this side of our globe reflect a brighter light,"

 

little credit is due to young George Washington's hatchet work. Fire in the hands of Neolithic man had already transformed the ecology -- and the albedo -- of Australia and the Americas eons before.

Working in the opposite sense, by converting woodlands into black water ponds, a Holocene population some population biologists estimate to have run into the hundred millions globally, may have engaged in wholesale SRM by darkening  some millions of square kilometers before <i> H. sapiens</i> even evolved. 

This unlicensed  landscape transformation was perpetrated by Castor faber  in the old world and C.canadensis in the new.

Ken also notes that "

It is not clear to me that the language of "state shift"adds much to this review of threats to (mostly) land ecosystems. However, whether you think it is a "state shift" or not, we surely are impacting Earth's biota on a grand scale.

I fear Malcolm Gladwell's 'Tipping Point' trope is itself  approaching the 'ONeilling Point', beyond which all use of an environmental cliche' is political.

[James Fleming]

That Franklin quote is only part of the story.  Is Africa's reflectivity lower due to racial makeup?

Which leads me to add one Remark: That the Number of purely white People in the World is proportionably very small. All Africa is black or tawny. Asia chiefly tawny. America (exclusive of the new Comers) wholly so. And in Europe, the Spaniards, Italians, French, Russians and Swedes, are generally of what we call a swarthy Complexion; as are the Germans also, the Saxons only excepted, who with the English, make the principal Body of White People on the Face of the Earth. I could wish their Numbers were increased. And while we are, as I may call it, Scouring our Planet, by clearing America of Woods, and so making this Side of our Globe reflect a brighter Light to the Eyes of Inhabitants in mars or Venus, why should we in the Sight of Superior Beings, darken its People? why increase the Sons of Africa, by Planting them in America, where we have so fair an Opportunity, by excluding all Blacks and Tawneys, of increasing the lovely White and Red? But perhaps I am partial to the complexion of my Country, for such Kind of Partiality is natural to Mankind.

-- Benjamin Franklin, America as a Land of Opportunity, 1751.

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--
James Fleming
STS Program
Colby College
5881 Mayflower Hill
Waterville, ME  04901
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