Quoting https://www.cnbc.com/2021/03/05/sand-shortage-the-world-is-running-out-of-a-crucial-commodity.html https://www.cnbc.com/2021/03/05/sand-shortage-the-wor

Quoting https://www.cnbc.com/2021/03/05/sand-shortage-the-world-is-running-out-of-a-crucial-commodity.html https://www.cnbc.com/2021/03/05/sand-shortage-the-world-is-r... : > The UN estimates that 4.1 billion tons of cement is produced every year, driven primarily by China See also https://www.statista.com/statistics/267364/world-cement-production-by-country/ https://www.statista.com/statistics/267364/world-cement-prod... . Concrete is about 2,000 kg/m³ - https://www.engineeringtoolbox.com/concrete-properties-d_1223.html https://www.engineeringtoolbox.com/concrete-properties-d_122... 704 years * 4.1 billion metric tons/year / (2,000 kg / m / m / m) / (510,064,472 km * km ) => 2.83 mm So, 704 years to cover the planet in 3mm of concrete. The article says "In a single year, there is enough to patio over every hill, dale, nook and cranny in England". I am not able to reproduce that. Using 130,279 km2 from https://en.wikipedia.org/wiki/Geography_of_England https://en.wikipedia.org/wiki/Geography_of_England (4.1 billion metric tons) / (2,000 kg / m / m / m) / (130,279 km * km) => 1.57 cm https://duckduckgo.com/?t=ffsb&q=concrete+patio+thickness&ia=web https://duckduckgo.com/?t=ffsb&q=concrete+patio+thickness&ia... suggests 4 inches is the minimum depth for a patio, or about 10 cm. Which means it would take about 6 years to patio England. FWIW, 4.1 billion metric tons/year * 10 seconds => 1.3 kilo tons 1.3 kilo tons / density of concrete => 650 kilo Liters 650 kL / 19,000 bathtubs => 32 liters per bathtub I doubt UK bathtubs are 32 L. I'm finding numbers like around 150-200 L for a bathtub - https://duckduckgo.com/?q=volume+of+a+bathtub+in+liters&t=ffsb&ia=web https://duckduckgo.com/?q=volume+of+a+bathtub+in+liters&t=ff... .