A return to the construction of houses made of wood and other biomaterials and the elimination of cement and concrete production will reduce global anthropogenic greenhouse gas emissions by about 20%. This was reported by the press service of the Potsdam Institute for Climate Research (PIK) with reference to an article in the journal Nature Sustainability.
"Urbanization and population growth are generating a constant demand for new homes, which will keep cement and steel as a major source of CO2. We can turn this into a global warming solution by encouraging the use of wood in the construction industry." - said Galina Churkina, climatologist from the Potsdam Institute for Climate Research, whose words are quoted by the PIK press service.
Cement was invented by the British engineer John Smeaton in the middle of the 18th century. Since then, its production technology and composition have not actually changed. It is a mixture of calcined limestone, clay and gypsum, which turns into a hard material, similar in properties to stone, when diluted in water and in contact with air.
Typically, cement is now produced by firing in clinker kilns. As a result, a large amount of CO2, soot, heavy metal ions, various corrosive gases and other hazardous substances enter the atmosphere. In terms of weight, these emissions are comparable to the weight of the cement produced, making this industry one of the largest sources of greenhouse gas emissions.
"Green" replacement for concrete
Churkina and her colleagues at the institute became interested in whether this problem can be solved in a radical way, significantly reducing or completely abandoning the use of concrete and cement in cases where they can be replaced with wood or other renewable building materials.
Guided by this idea, climatologists have calculated several options for how the level of emissions of CO2 and other greenhouse gases will change if 1%, 10%, 50% and 90% of building materials produced today from concrete and cement are replaced by their counterparts from wood and products other green technologies.
These calculations showed that in this case the construction industry will not be the largest source of anthropogenic greenhouse gas emissions, but will turn into one of their main sinks. For example, the construction of new residential and commercial buildings will absorb about 1 billion tons of carbon when replacing half of the cement and concrete structures with their wood counterparts, and about 250 million tons of greenhouse gases in the case of 10%.
Both of these indicators, as Churkina and her colleagues note, can be easily achieved by humanity if appropriate technologies and approaches are created that make it possible to quickly grow years and dispose of spent wood without returning the carbon stored in it to the atmosphere. If these plans are implemented, emissions associated with cement and concrete production will be reduced by about a third, replacing only 10% of these materials with wood.
If humanity abandons almost all such building materials, then the positive effect from this will exceed the overall level of emissions associated with the production of cement, and reach a level comparable to almost all industry involved in the processing of minerals. In this case, the total CO2 emissions will be reduced by 20%.
Such ideas, scientists hope, will help all countries of the world realize the main task of the Paris agreements - to keep global warming at 1.5 degrees Celsius and reduce CO2 emissions to near-zero values by the second half of the century.