Concrete: the most destructive material on Earth

Concrete: the most destructive material on Earth

SOURCE: The Guardian DATE: February 25, 2019 SNIP: In the time it takes you to read this sentence, the global building industry will have poured more than 19,000 bathtubs of concrete. By the time you are halfway through this article, the volume would fill the Albert Hall and spill out into Hyde Park. In a day it would be almost the size of China’s Three Gorges Dam. In a single year, there is enough to patio over every hill, dale, nook and cranny in England. After water, concrete is the most widely used substance on Earth. If the cement industry were a country, it would be the third largest carbon dioxide emitter in the world with up to 2.8bn tonnes, surpassed only by China and the US. Taking in all stages of production, concrete is said to be responsible for 4-8% of the world’s CO2. Among materials, only coal, oil and gas are a greater source of greenhouse gases. Half of concrete’s CO2 emissions are created during the manufacture of clinker, the most-energy intensive part of the cement-making process. But other environmental impacts are far less well understood. Concrete is a thirsty behemoth, sucking up almost a 10th of the world’s industrial water use. This often strains supplies for drinking and irrigation, because 75% of this consumption is in drought and water-stressed regions. In cities, concrete also adds to the heat-island effect by absorbing the warmth of the sun and trapping gases from car exhausts and air-conditioner units – though it is, at least, better than darker asphalt. Limestone quarries and cement factories are also often pollution sources, along...
Concrete is tipping us into climate catastrophe. It’s payback time

Concrete is tipping us into climate catastrophe. It’s payback time

SOURCE: The Guardian DATE: February 25, 2019 SNIP: Cement, the key component of concrete and one of the most widely used manmade materials, is now the cornerstone of global construction. It has shaped the modern environment, but its production has a massive footprint that neither the industry nor governments have been willing to address. Because of the heat needed to decompose rock and the natural chemical processes involved in making cement, every tonne made releases one tonne of C02, the main greenhouse warming gas. Nearly 6% of all UK greenhouse gas emissions, and up to 8% of the world’s, are now sourced from cement production. If it were a country, the cement industry would be the third largest in the world, its emissions behind only China and the US. So great is its carbon footprint that unless it is transformed and made to adopt cleaner practices, the industry could, on its own, jeopardise the whole 2015 Paris agreement which aims to hold worldwide temperatures to a 2C increase. Annual cement production has quadrupled from nearly one billion to over 4 billion tonnes a year in 30 years. In the next decade it is expected to increase a further 500m tonnes a year. Unless there is a dramatic change, cement emissions are expected to continue to rise beyond...
Is the world running out of sand? The truth behind stolen beaches and dredged islands

Is the world running out of sand? The truth behind stolen beaches and dredged islands

SOURCE: The Guardian DATE: July 1, 2018 SNIP: Our insatiable appetite for new buildings, roads, coastal defences, glass, fracking, even electronics, threatens the places we are designed by evolution to love most. The world consumes between 30 and 40bn tonnes of building aggregate a year, and half of this is sand. Enough material to build a wall 27m high and 27m wide around the equator. Sand is second only to water as a natural material extracted by humans, and our society is built on it, quite literally. Global production has risen by a quarter in just five years, fuelled by the insatiable demands of China and India for housing and infrastructure. Of the 15 to 20bn tonnes used annually, about half goes into concrete. Our need for concrete is such that we make almost 2 cubic metres worth each year for every man, woman and child on the planet. But what of those oceans of sand stretching from the Atlantic to the Persian Gulf – the Sahara and the Arabian Desert? The wrong kind of sand, unfortunately. Wind action in deserts results in rounded grains that are too smooth and too small to bind well in concrete. Builders like angular sand of the kind found on riverbeds. Sand, sand everywhere, nor any grain to use, to paraphrase Coleridge. Riverbed sand is prized, being of the correct gritty texture and purity, washed clean by running fresh water. Marine sand from the seabed is also used in increasing quantities, but it must be cleansed of salt to avoid metal corrosion in buildings. It all comes at a cost. International trade in...