Concrete. There’s a lot of it on earth. Pretty much every paradise has its parking lot. And its big-box store, high-rise condos, sidewalks, stadiums and office parks. Bridges, tunnels, jetties, locks, canals, station platforms: all require concrete.
Concrete is the second most consumed substance on earth (pdf), after water: three tons of it per year, per person on earth.
Manufacturing all that concrete is the second largest source of carbon emissions in the world, after energy generation, accounting for 5% of world CO2 emissions.
But a Californian company, Calera, has developed a solution.