Science
Carbon Capture & Storage Quiz
Direct air capture, BECCS, mineralization — 50 questions on climate's most controversial tool
Direct air capture, BECCS, mineralization — 50 questions on climate's most controversial tool
The world's largest direct-air-capture plant — Mammoth in Iceland — captures 36,000 tons of CO₂ per year, equivalent to about 8,000 cars taken off the road. That sounds impressive until you note that humanity emits over 37 billion tons of CO₂ annually — meaning Mammoth captures roughly one-millionth of global emissions. Yet the IPCC's AR6 report calls carbon dioxide removal (CDR) essential alongside emissions cuts to limit warming to 1.5°C. Whether through industrial direct air capture, natural carbon sinks, or geological storage, carbon capture has become one of the most debated technologies in the climate toolkit. This quiz covers the science, economics, companies, and controversies of the field.
Each round presents 10 randomized questions from a pool of 50, with four multiple-choice options and instant feedback after every answer. Your final score comes with a performance tier and shareable results.
You'll cover the difference between CCS and DAC, amine scrubbing and solid sorbents, geological storage in saline aquifers, Climeworks and Carbon Engineering, Norway's Sleipner project, BECCS, the US Inflation Reduction Act's 45Q tax credit, enhanced rock weathering, ocean alkalinity enhancement, the Frontier advance market commitment, and the costs and critiques of carbon removal at scale.
Direct air capture (DAC) is a technology that pulls CO₂ directly from the ambient atmosphere rather than from industrial exhaust stacks. Large fans push air through chemical sorbents (liquid or solid) that selectively bind CO₂. The CO₂ is then released, compressed, and either stored underground or used in products. Unlike point-source CCS, DAC can theoretically remove emissions from any source and even historical emissions.
Point-source CCS from industrial flues costs roughly $50–100 per tonne of CO₂. Direct air capture is far more expensive at $400–1,000 per tonne currently, because CO₂ is dilute in the atmosphere (about 420 ppm). The technology needs to fall below $100/tonne to be deployable at scale. The US Inflation Reduction Act's 45Q tax credit pays $180/tonne for DAC with geological storage.
Climeworks' Mammoth plant, opened in Iceland in 2024, is the world's largest direct air capture plant with a nameplate capacity of 36,000 tonnes of CO₂ per year. It is powered by geothermal energy and stores CO₂ underground using CarbFix's basalt mineralisation process. Climeworks' first commercial DAC plant, Orca (4,000 tonnes/year), also in Iceland, opened in 2021.
Last updated: May 2026