Even if the world stopped all greenhouse gas emissions tomorrow, the carbon already in the atmosphere would continue driving warming for decades. That reality has pushed carbon removal — actively pulling CO2 out of the air — from a fringe idea to a central component of climate strategy. But the gap between what is needed and what exists is staggering.
The book explored climate science through The Day After Tomorrow and covered the broader challenges in the Climate Science and Geoengineering pages. Carbon removal was a concept then; it is now an industry — though a very small one relative to the scale of the problem.
Direct air capture (DAC) — using chemical processes to extract CO2 directly from ambient air — has moved from laboratory demonstration to commercial operation. Climeworks operates the world's largest DAC facility in Iceland, where captured carbon is mineralized underground. Occidental Petroleum (through its Carbon Engineering acquisition) is building a much larger facility in Texas. But current global DAC capacity removes roughly tens of thousands of tons of CO2 per year. The atmosphere contains about 3.2 trillion tons. The scale gap is not incremental — it is orders of magnitude.
Nature-based solutions include reforestation, soil carbon sequestration, biochar (converting biomass to stable charcoal and burying it), and ocean alkalinity enhancement (adding alkaline minerals to seawater to increase its capacity to absorb CO2). These are generally cheaper than engineered approaches but harder to verify, less permanent, and subject to reversal through wildfires, land use changes, or changes in ocean chemistry.
Carbon markets have grown rapidly but face integrity problems. Carbon credits — tradable units representing the removal or avoidance of one ton of CO2 — have been plagued by questions about whether the claimed reductions are real, additional, and permanent. Multiple investigations have found that a significant proportion of forest-based carbon credits represent reductions that would have happened anyway.
The book's Hype vs. Reality framework is essential here. Carbon removal is surrounded by claims from both optimists ("technology will solve climate change") and skeptics ("it's a fossil fuel industry distraction"). Counting assumptions — the book's Occam's Razor discipline — reveals that the optimistic scenario requires massive scaling of unproven technology, enormous capital investment, and political will to continue for decades. Each assumption is individually plausible but the stack is tall.
The distraction risk is real. If governments and corporations treat carbon removal as a substitute for emission reductions rather than a complement, the net effect could be harmful. The book's Resilience and Adaptation framework argues for strategies that maintain options and avoid single points of failure — which in climate terms means pursuing emission cuts and carbon removal simultaneously, not choosing between them.
Intergenerational Responsibility is unavoidable. Current carbon removal infrastructure is being built to address emissions from past and present generations. The costs and maintenance burdens will fall on future generations. The question of what we owe those who come after us — explored in What do we owe people who haven't been born yet? — is nowhere more concrete than here.