At the same time, climate policy may do more than we realize. Timothy Searchinger, a land scientist at Princeton who was not involved in the new report, told me that the IPCC may undercount the benefits of land policy specifically. The panel does not always assume that farmers, for instance, will get better at capturing carbon if paid to do so, even though technology almost always improves in such circumstances, he said.
Read: How climate change could trigger the next global financial crisis
But on our current trajectory—and on any trajectory, frankly, where the United States does not adopt a serious climate policy—it’s far more likely that the planet will warm at least 3 degrees Celsius (5.1 degrees Fahrenheit) by 2100. That means that average land temperatures will be 10 degrees Fahrenheit hotter than they are today.
The IPCC warns that people who live on such a planet will face a “very high risk” of famine, water scarcity, and mass vegetation die-offs. Some of the people who will see that planet have already been born.
7. Let’s return to that one astonishing fact: that humans have integrated as much as one-third of photosynthesis on land into the global economy. This statistic captures not only the rice or broccoli or carrots on your plate, but the coffee in your mug, the cotton fiber in your socks, the oak heartwood in your kitchen table, and the linseed oil in your linoleum floor.
What’s incredible about this fact is not only the scale of economic production that it entails. It’s that photosynthesis isn’t even the energetic part of the economy. What we call “the energy sector” still mostly consists of fossil fuels: oil, coal, and natural gas. Those three fuels generated 80 percent of the energy used in the United States in 2017, at least by a traditional accounting. Of course, fossil fuels are themselves just concentrated sunlight: The Permian oil basin in Texas is so named because it holds the gloopy product of photosynthesis made during the Permian period, more than 251 million years ago. And there’s a view of climate change as a massive spending spree, the end result of humanity spending down its 600-million-year inheritance.
But that’s not my point. To address climate change, we will need to reduce our use of fossil fuels, and replace energy generated in the past (by long-dead plants) with energy generated today (by wind turbines, solar panels, and uranium atoms). But, this report adds: We must do all that in a house of only 52 million rooms, the majority of which already serve as someone’s bedroom, bathroom, or kitchen. And those 52 million rooms must stage not only the unending drama of the human family, but also—as far as we know—every other living thing in the universe.
How are you even supposed to talk about that? More than 30 years after climate change first became a political issue, it feels like we are still figuring it out. This report gets us closer. It makes clear that climate change isn’t only about coal-fired power plants, or gas-guzzling cars; and it’s definitely not about littering or—God help us—recycling. It’s about the profound chemical and physical specificity of human life. You and I are not free-floating minds that move around the world through text messages, apologetic emails, and bank deposits. We are carbon-based creatures so pathetic that we need a lot of silent plants to make carbon for us.
Climate change requires us to alter the biogeochemical organism that we call the global economy on the fly, in our lifetimes. Such a task should command most of the time and attention of every economist, agriculturalist, investor, executive, and politician—anyone who fancies themselves a leader in the physical workings of the economy, or whatever we call it. It is our shame, and theirs, that they don’t.