David Wallace-Wells divides his book, The Uninhabitable Earth: Life After Warming, into four sections, each dealing with the effects of a warmer planet on human life. The first, “Cascades”, deals with the general notion that every single climate event will trigger a multitude of effects. For human civilization, this will mean a multiplying of stresses all amplifying the seriousness of each other in a “cascade” of complex problems, none of which can be solved without solving all the others. Once problems reach some unspecified level of disruption, they become so interconnected that they overwhelm our ability to address them. This means that we regress rather than progress. And just as progress tends to amplify itself, the same applies to the deconstruction process, until the structure of a civilization is so riddled with dysfunction that it is no longer viable.

In the second section of his book, called “Elements of Chaos”, Wallace-Wells explores 12 of them. The themes can usually be identified by the titles: 

• “Heat Death”—parts of the planet will be too hot for normal outside work or even for human habitation. 
• “Hunger”—rising temperatures and extreme weather will cause increasingly large crop failures. 
• “Drowning”—oceans will continue their unstoppable rise, inundating hundreds of coastal cities and crop-growing areas, supplemented by floods from extreme precipitation that will cause inland havoc. 
• “Wildfires”—they will become more common, hotter, less predictable, and will accelerate the climate change disaster. 
• “Disasters No Longer Natural”—many disasters, previously called “natural”, will have to be attributed to human behaviour, with widespread philosophical, psychological and political ramifications. 
• “Freshwater Drain”—the 1% of the water on Earth that is fresh and available for human use will become increasingly scarce as populations rise, as agricultural needs expand, and as droughts become more common.
• “Dying Oceans”—acidification and rising water temperature will reduce the ability of oceans to provide food.
• “Unbreathable Air”—in addition to the deleterious effects of particulate air pollution, higher levels of atmospheric carbon dioxide will impair human cognition, and will eventually be deleterious to plant growth.
• “Plagues of Warming”—a warming planet will lure diseases and pests northward, bringing new plagues and parasites to places that were once immune to them.
• “Economic Collapse”—economic security is dependent on social, political and environmental stability, all of which will be stressed by global climate change.
• “Climate Conflict”—environmental, resource and migration stresses will intensify geopolitical tensions and increase the likelihood of internal civil unrest and multinational wars.
• “Systems”—system failure is another term for the “threat multiplier” that will occur when the networks that stabilize and harmonize human interactions begin to fail. 

Wallace-Wells calls the third section of his book “The Climate Kaleidoscope”, by which he means the ways in which the climate crisis is broken down into such disconnected fragments that we fail to recognize it as an actual crisis. This section of the book is divided into six parts:

• “Storytelling”—we have a long history in our mythology about impending apocalypses, but they are so rendered as fiction that they keep us from recognizing the impending climate crisis as an actual event.“Crisis Capitalism”—we have a huge, complicated and demanding economic system that is devouring the very resources that it needs to survive, while denying that this is happening. 
• “The Church of Technology”—our worship of technology incorrectly assures us that some invented technology is going to save us from the same problems that were created by technology.
• “Politics of Consumption”—to consume is to prosper, a strategy that will ultimately destroy our ability to consume. 
• “History After Progress”—when our traditional measure of progress is stripped from our sense of history, we will be bewildered by what to do next.
• “Ethics as the End of the World”—various speculative dystopias are considered as people try to understand what remains of an entire civilizational structure that could collapse on itself.

Part four, called “The Anthropic Principle”, is based on the scientific reality of our situation and is, in effect, the summary message of the book. Our prospective future, unlike the past, will no longer be based on the vagaries of nature, but on our own decisions. We have become such a dominant influence in determining the behaviour of Earth’s key ecosystems that what befalls us and life on our planet will be determined by the course of action or inaction that we choose. The proposed name for this geological epoch, the Anthropocene, is an acknowledgement of this influence and the immeasurable weight of responsibility that it places on us, not only for our own survival as an orderly civilization, but for a continuation of the natural ecologies that have supported and enriched our existence as a species. 

We now have the option of controlling our future to an unprecedented extent. We know what we are doing to our planet, we have a fairly clear idea of what the disruptive effects will be, and we understand what we have to do to avoid an unfolding catastrophe. We are already getting an uncomfortable sample of these changes. Some are so firmly established in Earth’s ecological systems that they cannot be stopped. As for what happens next, that will be determined by the choices we make now. 

Ray Grigg for Sierra Quadra