Gaia Is Dead

Gaia is dead, and Toby Tyrrell has killed her.

Book Cover

This is a brief review of On Gaia: A Critical Investigation of the Relationship Between Life and Earth by Toby Tyrrell.

It’s a devastating book. Devastating, that is, to the Gaia hypothesis. It’s also quite fascinating. This is recommended reading for anyone who lives on Earth and has a brain.

The author aims to investigate the hypothesis, formulated by James Lovelock in the 1970s, “that life has played a critical role in shaping the planetary environment and climate over ~3 bil­lion years, in order to keep it habitable or even optimal for life down through the geological ages.” (From Q&A with Toby Tyrrell)

Tyrrell offers evidence and argument in roughly equal measure. The empirical evidence is drawn from a diverse array of sources, most notably evolutionary biology and Earth system science. The philosophical arguments include an extended meditation on the anthropic principle and its implications.

For non-scientists, at least, it’s perhaps too easy to dismiss the empirical data. The critical reader, if not familiar with the current research literature, can’t help but wonder if the author is selectively presenting only evidence that supports his agenda. The philosophical arguments can be understood by anyone, regardless of specialization, and are much harder to discount.

On both fronts, in chapter after chapter, Tyrrell finds the case for Gaia doesn’t hold up. He gives credit to Lovelock for major insights that have proven correct, and for generally provoking scientists and the general public to think about life on Earth in a new way. But at the end of the book, Gaia has been thoroughly dismantled.

So where does that leave us? Tyrrell winds up with an excellent discussion on just why all this stuff matters. He points out that any notion of Gaia as a self-sustaining, self-regulating system may lead to complacency. We may be tempted to believe that environmental problems will tend to correct themselves. In other words, Gaia may lead us to “undue optimism.” It’s important for humanity to realize that we cannot rely on built-in safeguards to save our proverbial bacon. The global ecosystems which sustain us are more precarious than a strong Gaian view might lead us to believe. If we are to protect our home from the effects of our own depredations, we must dispense with the erroneous notion of a self-healing Earth.

In other words, in order to save Gaia, it is necessary to destroy her.

Next week: Spiritual and religious implications of Tyrrell’s critique.