think of climate change as slow, but it is unnervingly fast. We think of the technological change necessary to avert it as fast-arriving, but unfortunately it is deceptively slow—especially judged by just how soon we need it. This is what Bill McKibben means when he says that winning slowly is the same as losing: “If we don’t act quickly, and on a global scale, then the problem will literally become insoluble,” he writes. “The decisions we make in 2075 won’t matter.” Innovation, in many cases, is the easy part. This is what the novelist William Gibson meant when he said, “The future is already here, it just isn’t evenly distributed.” Gadgets like the iPhone, talismanic for technologists, give a false picture of the pace of adaptation. To a wealthy American or Swede or Japanese, the market penetration may seem total, but more than a decade after its introduction, the device is used by less than 10 percent of the world; for all smartphones, even the “cheap” ones, the number is somewhere between a quarter and a third. Define the technology in even more basic terms, as “cell phones” or “the internet,” and you get a timeline to global saturation of at least decades—of which we have two or three, in which to completely eliminate carbon emissions, planetwide. According to the IPCC, we have just twelve years to cut them in half. The longer we wait, the harder it will be. If we had started global decarbonization in 2000, when Al Gore narrowly lost election to the American presidency, we would have had to cut emissions by only about 3 percent per year to stay safely under two degrees of warming. If we start today, when global emissions are still growing, the necessary rate is 10 percent. If we delay another decade, it will require us to cut emissions by 30 percent each year. This is why U.N. Secretary-General António Guterres believes we have only one year to change course and get started. The scale of the technological transformation required dwarfs any achievement that has emerged from Silicon Valley—in fact dwarfs every technological revolution ever engineered in human history, including electricity and telecommunications and even the invention of agriculture ten thousand years ago. It dwarfs them by definition, because it contains all of them—every single one needs to be replaced at the root, since every single one breathes on carbon, like a ventilator.