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Earth and Mars - spot the difference? Image: RHorning, modified by Scooter20 via Wikimedia Commons.
Earth and Mars - spot the difference? Image: RHorning, modified by Scooter20 via Wikimedia Commons.
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Climate change and the living Gaia

Lee Klinger

10th January 2015

Debate around climate change is based on the idea that Earth is a purely physical and chemical entity, writes Lee Klinger. But what if Earth is a living system? Then things could turn out very differently - and we understand how, we need to develop a new Gaian science of planetary physiology.

If the earth is a living system, then the climate models are clearly inadequate for the task of climate prediction, as living systems defy quantification, and are highly non-linear in their behavior.

As an independent scientist who worked for many years at the National Center for Atmospheric Research, a leading institution in the study of climate, I am often asked about my views on climate change.

Those who know me seem to appreciate my perspective, as I have no political agenda or financial stake in the issue of climate change.

I receive no funding for my research or publications on climate science. My motivation to study and write comes solely from a deep curiosity around the nature of the earth.

Two global theories

Climate science requires a global theory, which, if accurate, fairly explains the past, present, and future behaviors of the earth system. Two global theories have been proposed.

The predominant theory is, in essence, that the earth is a non-living planet that supports life and is ultimately explainable through first principles of physics and chemistry.

The details of this approach, which I call the 'standard earth theory', are seen in the formulations of the many mathematical models of climate. While these and other Earth system models include certain biological processes and feedbacks, the influence of biology is minor compared to the physics and chemistry.

A second theory postulates that the Earth is living planet, and that the behavior of the planet is explainable through understanding feedbacks of physics and chemistry with ecosystems. Generally known as Gaia theory, this view considers the many biological and ecological couplings with air, land, and ocean that are involved in the self-regulation of a living planet.

As living systems are not reducible to mathematical formula, predictive models of a living earth, like other models of living systems, focus on characterizing past behaviors under a variety of conditions in order to forecast future behaviors.

Expanding the debate

In the debate around anthropogenic climate change, it is important to recognize that nearly all of the scientists involved, supporters and skeptics alike, are following the standard earth theory.

Much of the debate is centered on the degree to which humans affect climate. Many scientists believe that greenhouse gas emissions (e.g., CO2 and CH4) are the primary drivers of climate change.

Other scientists argue that humans' effect on landscape change is as important, or more important, than greenhouse gas emissions in climate change. And other scientists believe that humans are having only a small impact on climate and that most of the changes we are seeing are due to natural climatic cycles and variations.

I must emphasize that if the Earth is not a living system, then considering that non-living systems tend to be loosely regulated, the predictions of the climate models, whether or not one believes them too alarming, are to be taken seriously.

While the standard Earth theory may be valid, my overarching sense is that Gaia theory offers a better interpretation of the Earth. At the very least, Gaia theory deserves fair consideration in an expanded debate on climate change.

James Lovelock, originator of Gaia theory, has offered his view that the living earth is currently in a sickly, "feverish" state due to greenhouse gas emissions, and that, while Gaia will survive, humans will be severely impacted by continued global warming.

Lovelock's radical views appear to have been marginalized by both sides of the climate debate. But what if Gaia is not in a feverish state? Is there evidence that the planet is healthy enough to mitigate the effects of greenhouse gases?

Possible Gaian feedbacks

Let me offer three key phenomena that suggest regulatory feedbacks are operating at the planetary scale at the present time, consistent with Gaia theory.

First is the mystery of Earth's 'missing carbon'. For several decades scientists have been trying to account for a significant fraction of carbon that is being released by fossil fuel emissions, but is not accumulating in the atmosphere.

A Gaian take on the missing carbon involves accounting for key biological feedbacks, such as CO2 fertilization, which induces plants to take up more carbon, and the advance of forests, which are expanding aggressively in places where disturbance regimes have been subdued.

Second is the leveling off of global temperatures in the 21st century. During the 20th century the Earth underwent a warming trend of ~1.4°F / 0-.8°C. Since the year 2000 global temperatures have stabilized and there has been little or no significant warming trend, depending on the temperature series being considered.

Most climate models have failed to predict this hiatus in global temperatures (though explanations have been advanced retrospectively). Gaia theory would point to feedbacks of biogenic aerosols altering the reflectivity of the atmosphere, as well as actions of biological organisms in mediating water vapor flux to the air and in seeding clouds.

Third is the curious behavior of global sea ice. Since 1979, when satellite records of sea ice began, Arctic sea ice has declined by more than a million square kilometers, as would be expected from warming temperatures. Antarctic sea ice, however, has grown more than a million square kilometers over the same period, which is at odds with the climate model projections. Could Gaia be at work here?

With respect to Antarctica, we know that microbes (e.g., bacteria, diatoms) can significantly influence sea ice formation. Studies have also shown that iron fertilization from glacial meltwaters plays a significant role in the biology of sea ice.

Thus, the conditions exist for a possible self-regulating Gaian feedback linking glacier dynamics, sea ice formation, and cloud formation via microbial ecosystems.

The problematical mathematics of Gaia

If the Earth is a living system, then the climate models are clearly inadequate for the task of climate prediction, as living systems defy quantification, and are highly non-linear in their behavior.

In mathematical terms, the Earth system is definable as a multitude (many billions would be a gross underestimate) of coupled non-linear equations, all being solved simultaneously.

At present we can count on the fingers of our hands the number of coupled nonlinear equations that, when solved together, produce anything other than chaos using our current mathematical techniques.

I suspect few people realize the tremendous mathematical achievements still required to fairly characterize the earth, or for that matter any living system, using models based on physics and chemistry.

That is not the say that the behavior of the living earth is not, to a degree, predictable, only that it is not mathematically predictable from first principles. Personally, I believe we still need decades of observational studies on the role of the biota in the Earth system before any useful predictive global models can be constructed.

Regarding the science of climate change, it is my observation that many scientists on both sides of the debate are expressing a much higher level of confidence in their findings than is warranted by the data. This comes, in part, from the sincere belief that physical / chemical models are, indeed, the best representations of the Earth system.

However, if there is validity in Gaia theory, then the attention should turn to empirical studies of biotic feedbacks and periodic behaviors of the earth in an attempt to meticulously describe the planetary physiology, so as to better inform our future.



Lee Klinger is an independent scientist with over 30 years of experience in the environmental sciences at major institutions in the US, UK, and China. He has numerous publications in the fields of ecology, botany, atmospheric chemistry, and Earth system science; and has held scholarly appointments at the National Center for Atmospheric Research, the University of Colorado, Oxford University, and the Chinese Academy of Sciences. He currently lives in Big Sur, California where he has been doing tree and forest restoration work for more than 10 years. His website is



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