Requiem for a grand theory
- Nature Climate Change
- Published online
On Gaia: A Critical Investigation of the Relationship between Life and Earth
Gaia, the brainchild of James Lovelock, was born in 1972. The historical constancy of Earth's chemical conditions and climate seemed just too much for chance alone. In Gaia it is postulated that the Earth's conditions were determined by the biosphere and regulated for the further benefit of life's persistence and activity. Gaia has motivated a huge number of biogeochemists to think about ecology on the planetary scale, and to examine what causes the movement and transformation of elements in global cycles. The theory has survived withering criticism and numerous international conventions — some to extend its reach and others to bandage a wounded Gaia with modifications and caveats. Even now, when students read Lovelock's first book on Gaia they engage with his insights enthusiastically.
In this book, Toby Tyrell — a professor of Earth science at the University of Southampton — offers a systematic, dispassionate, retrospective examination of Gaia. It will be hard to ignore the flaws in Gaia, illustrated nicely in a table showing the success and failure of Gaia relative to some alternative theories based on the geosciences and coevolution. In the face of data, Gaia fails in its idea that the Earth is held at conditions optimal for life. Using net primary production and biodiversity as metrics, Tyrell finds that the Earth is actually too cold for the maximum development of the biosphere. Gaia also fails in its postulate that the Earth is held at relatively stable conditions. True, the climate and biogeochemical cycles of the Holocene [the past ~11,000 years] have been unusually stable, but over longer periods of time the biosphere has been buffeted by events that have dealt it quite a blow. What is remarkable is that life persisted at all — a statement of the power of evolution to rebuild the biosphere everywhere as long as life has endured somewhere...
Schlesinger's review goes on to say, "Tyrell warns us of the dangers of Gaia. Those who believe that our planet is self-regulating will lack any motivation to stem the growing tide of human insults to Earth's atmosphere, oceans and terrestrial biosphere from a rising human population with great expectations for well-being. These libertarians need to know that their belief is groundless. CO2 will increase in Earth's atmosphere as long as we add more of it from fossil fuel combustion than the oceans can absorb each year by Henry's Law."ReplyDelete
A self-regulating system would be in your favor, no? As you can see, by including more of the review, it takes on a very different shape. The abandonment of the Gaia theory, and any proposed self-regulatory system, actually does more to hurt your arguments than help.
Use brain more, copy/paste less.
Oh please, I don't base any of my arguments upon Gaia theory, and the portions of the review I included above already poke holes in Gaia, e.g. "It will be hard to ignore the flaws in Gaia, illustrated nicely in a table showing the success and failure of Gaia relative to some alternative theories based on the geosciences and coevolution. In the face of data, Gaia fails in its idea that the Earth is held at conditions optimal for life." which immediately precedes the quote about Earth being "too cold".Delete
The fact is that the past 4.5 billion years prove that Earth has been remarkably stable due to negative feedbacks exceeding positive, with no runaway greenhouse effect despite CO2 levels 20 or more times higher than the present.
I wanted to thank you for this great read!!ReplyDelete