A recent study examined how green clay tennis courts in the United States can remove carbon dioxide through enhanced rock weathering. The courts are made of metabasalt, a basalt type whose chemical reactions with rainwater draw down carbon. The researchers used a database listing court locations and surface types and analysed 17,178 green clay courts.
They calculated gross and net carbon sequestration while accounting for emissions from mining, processing, transport, court construction and maintenance. The estimates used basalt type, grain size of the crushed rock, court temperature and chemical composition. The team compared these results with models for hard courts.
The researchers estimate the courts remove about 25,000 metric tons of CO2 per year. They report that 80% of courts reach net zero in fewer than 10 years, 92% within 20 years, and the median time to net negative is about 3.5 years. A small group of courts in cold, distant regions may never reach net zero.
Difficult words
- weathering — natural chemical or physical breakdown of rocks
- metabasalt — a type of basalt rock with certain minerals
- basalt — dark volcanic rock common in Earth's crust
- sequestration — long term storage of carbon in rocks
- grain size — diameter of the small pieces of rock
- emission — gases released into the atmosphere from activitiesemissions
- net zero — when total emissions equal total removals
- net negative — when removals exceed emissions overall
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Discussion questions
- Would you support building more courts made of crushed basalt to reduce carbon? Why or why not?
- The article says some courts in cold, distant regions may never reach net zero. What local conditions there could cause this?
- The researchers counted emissions from mining, processing, transport, construction and maintenance. Which of these could be reduced most easily in your opinion, and how?
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