If the concrete used on the planet were a country, it would be the third largest emitter of greenhouse gases in the world, behind China and the United States. So to limit its carbon footprint, manufacturers are working to find greener formulas that are more responsive to rising temperatures. One example is "earth concrete", on which Saint-Gobain, the world leader in building materials, is working, but which some specialists in the sector see as nothing more than greenwashing. IMAGES AND SOUNDBITES ARRANGED IN SEQUENCES N°33CM47N