I’ve been enjoying this book:
• Tim Lenton and Andrew Watson, Revolutions That Made the Earth, Oxford U. Press, Oxford, 2011.
It’s mainly about the history of life on Earth, and how life has affected the climate and atmosphere. For example: when photosynthesis first started pumping a deadly toxic gas into the atmosphere—oxygen—how did life evolve to avoid disaster?
Or: why did most of the Earth freeze, about 650 million years ago, and what did life do then?
Or: what made 96% of all marine species and 70% of vertebrates on land die out, around 250 million years ago?
This is the book’s strength: a detailed but readable version of the greatest story we know, complete with mysteries yet to be solved. But at the end they briefly ponder the future. They consider various scenarios, lumped into three categories: apocalypse, retreat or revolution.
They begin by reviewing the familiar story: how soaring population and fossil fuel usage is making our climate ever hotter, making our oceans ever more acidic, and sucking phosphorus and other nutrients out of ground and into the sea.
They consider different ways these trends could push the Earth into a new, inhospitable state. They use the term ‘apocalypse’. I think ‘disaster’ is better, but anyway, they write:
Even the normally cheerful and creative Jim Lovelock argues that we are already doomed, and nothing we can do now will stop the Earth system being carried by its own internal dynamics into a different and inhospitable state for us. If so, all we can do is try to adapt. We disagree—in our view the game is not yet up. As far as we can see no one has yet made a convincing scientific case that we are close to a global tipping point for ‘runaway’ climate change.
Yet even without truly ‘runaway’ change, the combination of unmitigated fossil fuel burning and positive feedbacks from within the Earth system could still produce an apocalyptic climate for humanity. We could raise global temperature by up to 6 °C this century, with more to come next century. On the way there, many parts of the Earth system could pas their own thresholds and undergo profound changes in state. These are what Tim [Lenton] and colleagues have called ‘tipping elements’ in the climate system.
They warrant a book by themselves, so we will just touch on them briefly here. The tipping elements include the great ice sheets covering Greenland and West Antarctica that are already losing mass and adding to sea level rise. In the tropics, there are already changes in atmospheric circulation, and in the pattern of El Niño events. The Amazon rainforest suffered severe drought in 2005 and might in the future face a climate drying-triggered dieback, destroying biodiversity and adding carbon to the atmosphere. Over India, an atmospheric brown cloud of pollution is already disrupting the summer monsoon, threatening food security. The monsoon in West Africa could be seriously disrupted as the neighboring ocean warms up. The boreal forests that cloak the northern high latitudes are threatened by warming, forest fires and insect infestation. The list goes on. The key point is that the Earth’s climate, being a complex feedback system, is unlikely to respond in an entirely smooth and proportional way to significant changes in energy balance caused by human activities.
Here is a map of some tipping elements. Click for more details:
A popular answer to apocalyptic visions of the future is retreat, into a lower energy, lower material consumption, and ultimately lower population world. In this future world the objective is to minimize human effects on the Earth system and allow Gaia to reassert herself, with more room for natural ecosystems and minimal intervention in global cycles. The noble aim is long-term sustainability for for people as well as the planet.
There are some good and useful things we can take from such visions of the future, especially in helping to wean ourselves off fossil fuels, achieve greater energy efficiency, promote recycling and redefine what we mean by quality of life. However, we think that visions of retreat are hopelessly at odds with current trends, and with the very nature of what drives revolutionary changes of the Earth. They lack pragmatism and ultimately they lack ambition. Moreover, a retreat sufficient to forestall the problems outlined above might be just as bad as the problems it sought to avoid.
Our alternative vision of the future is of revolution, into a high energy, high recycling world that can support billions of people as part of a thriving and sustainable biosphere. The key to reaching this vision of the future is to learn from past revolutions: future civilizations must be fuelled from sustainable energy sources, and they must undertake a greatly enhanced recycling of resources.
And here is where the lessons of previous ‘revolutions’ are especially useful. As I said last time, they list four:
1. The origin of life, before 3.8 billion years ago.
2. The Great Oxidation, when photosynthesis put oxygen into the atmosphere between 3.4 and 2.5 billion years ago.
3. The rise of complex life (eukaryotes), roughly 2 billion years ago.
4. The rise of humanity, roughly 0 billion years ago.
Their book argues that all three of the earlier revolutions disrupted the Earth’s climate, pushing it out of stability. It only restabilized after reaching a fundamentally new state. This new stable state could only be born after some new feedback mechanisms had developed.
For example, in every revolution, it has been important to find ways to recycle ‘wastes’ and make them into useful ‘resources’. This was true with oxygen during the Great Oxidation… and it must be true with our waste products now!
In any sort of approximate equilibrium state, there can’t be much ‘waste': almost everything needs to be recycled. Serious amounts of ‘waste’ can only occur for fairly short periods of time, in the grand scheme of things. For example, we are now burning fossil fuels and creating a lot of waste CO2, but this can’t go on forever: it’s only a transitional phase.
Apocalypse and Revolution?
I should talk about all this in more detail someday. But not today.
For now, I would just like to suggest that ‘apocalypse’ and ‘revolution’ are not really diametrically opposed alternatives. All three previous revolutions destroyed the world as it had been!
For example, when the Great Oxidation occurred, this was an ‘apocalypse’ for anaerobic life forms, who now struggle to survive in specialized niches here and there. It only seems like a triumphant ‘revolution’ in retrospect, to the new life forms that comfortably survive in the new world.
So, I think we’re headed for a combination of apocalypse and revolution: the death of many old things, and the birth of new ones. At best we have a bit of influence in nudging things in a direction we like. I don’t think ‘retreat’ is a real option: nostalgic though I am about many old things, time always pushes us relentlessly into new and strange worlds.