After decades of debate, the Gaia puzzle may have been solved

Scientists may have finally unraveled the mystery of how conditions on our planet have remained stable enough for life to persist over billions of years, despite catastrophic threats such as volcanoes and meteor strikes.

The “Gaia” hypothesis suggests that the interaction between living things and inorganic processes has somehow managed to strike the right balance. Exactly how this may work, however, has been the subject of debate for many years. A research team led by the University of Exeter recently proposed a likely solution.

“We can now explain how the Earth has accumulated stabilizing mechanisms over the past 3.5 billion years of life on the planet,” said study co-author Professor Tim Lenton.

“The central problem with the original Gaia hypothesis was that evolution via natural selection cannot explain how the whole planet came to have stabilizing properties over geologic timescales.”

“Instead, we show that at least two simpler mechanisms work together to give our planet with life self-stabilising properties. Our findings can help explain how we came to be here to wonder about this question in the first place.”

The experts determined that the planet’s stability most likely comes from “sequential selection.” In this process, the environment is only destabilized by life for a short time and subsequent changes continue until stable conditions emerge.

As the steady conditions persist, the system has more time to acquire traits that help to maintain its stability, which is a process known as “selection by survival alone.”

Study co-author Dr. James Dyke is an associate professor of Sustainability Science Within Geography and Environment at the University of Southampton.

“As well as being important for helping to estimate the probability of complex life elsewhere in the universe, the mechanisms we identify may prove crucial in understanding how our home planet may respond to drivers such as human-produced climate change and extinction events,” said Dr. Dyke.

Professor Dave Wilkinson of the University of Lincoln is also a co-author of the study.

“I have been involved in trying to figure out how Gaia might work for over 20 years – finally it looks like a series of promising ideas are all coming together to provide the understanding I have been searching for,” said Professor Wilkinson.

The Gaia hypothesis was first proposed by James Lovelock in the 1970s and is named after the god who personified the Earth in Greek mythology.

The study is published in the journal Trends in Ecology and Evolution.

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By Chrissy Sexton, Earth.com Staff Writer