麻豆传媒

Earth is a complex machine that works to support life 鈥� and humans have seized the controls, for better or worse. That was the message of a conference held last聽week to celebrate the 100th birthday of James Lovelock, who famously came up with the Gaia hypothesis.

Lovelock鈥檚 idea is that life on聽Earth acts to preserve its own聽existence, by stabilising conditions on the planet. Popularised in the 1970s, it inspired a generation of scientists who study Earth鈥檚 many systems, from the climate to forests, and how they interact as a whole.

Lovelock is famously independent-minded, and his idea has attracted more than its share of eccentrics. This was evident throughout the conference, named The Future of Global Systems Thinking: Celebrating James Lovelock鈥檚 Centenary and held at the University of Exeter, UK. At one point, musician Peter Horton of Gaia鈥檚 Company聽鈥� a group that runs workshops and cultural performances that explore the Gaia hypothesis鈥� themes聽鈥� sang a bouncy song about how everything about us is聽made by and part of Gaia, from our bones to our flatulence.

This silliness sat alongside a serious message. Humans are now pushing Earth鈥檚 systems out of whack, for instance by releasing more greenhouse gases than living organisms can mop up, and聽so heating up the planet. As聽a聽result, July may have been the聽world鈥檚 warmest month in recorded history.

Scientists at the conference described the many impacts humans are having on the planet. For the first time in geological history, Gaia has conscious beings at the controls: a situation dubbed 鈥淕aia 2.0鈥� by Tim Lenton at the University of Exeter and philosopher Bruno Latour of Sciences Po in Paris, France.

Living in Gaia

The evidence that our impact on Gaia is harmful is overwhelming. Ricarda Winkelmann of the Potsdam Institute for Climate Impact Research in Germany described how the warming of the planet, caused by our greenhouse gas emissions, is melting the great ice sheets of Greenland and Antarctica. The two sheets contain enough water to raise the global sea level by 65 metres.

The Greenland ice sheet in particular looks very unstable. Melting the top layer of the ice means the new top is at a lower altitude, where temperatures are warmer. 鈥淭hat means there can actually be a critical temperature, associated with a critical elevation, at which there is no other solution but for Greenland to become ice-free,鈥� Winkelmann said.

The enormous volumes of plastic we produce and (often) immediately throw away was highlighted by Tamara Galloway of the University of Exeter. As plastic waste in the ocean has become a widespread concern, some have argued that this is 鈥渁聽cosmetic issue鈥� and not a fundamental threat.

However, Galloway argues that this is a mistake, because plastics are made from petrochemicals, so聽contribute to climate change. She highlighted a 2019 report by聽the Center for International Environmental Law, which found that the production and use of plastics will emit 0.86 billion tonnes of carbon dioxide equivalent this year. 鈥淭hat equates to 3.8 per cent of total carbon emissions,鈥� said Galloway.

So what would it take to repair the damage we have inflicted on Gaia鈥檚 self-regulating systems, and聽begin to live sustainably within them? The solution, many delegates argued, is to redesign society (and our culture) so that it聽is better suited to Gaia.

To avoid dangerous levels of聽global warming, we urgently need to cut our greenhouse gas emissions. However, we have left聽it聽so late to act that many scientists are now also looking

at technologies to artificially remove and store atmospheric carbon dioxide (see 鈥淪ucking carbon from air鈥�, page 18).

One such approach, developed by Tim Flannery of the Australian Museum in Sydney, is a scheme to grow seaweed in the open ocean by pumping nutrient-rich deep water to the surface. Once grown, the seaweed could be sunk, trapping huge amounts of carbon. At the conference, Flannery cited a 2012 study which estimated that covering 9 per cent of the ocean surface with seaweed would remove enough carbon dioxide to聽restore the atmosphere to a pre-industrial level.

However, many speakers raised聽the spectre of unintended consequences for such geoengineering projects.聽 For聽example, a huge increase in seaweed could deprive marine animals of oxygen. The fact that such ideas are being considered at all 鈥渟hows how desperate people are getting鈥�, Lenton told me.