Email from a reader: Hello, my name is Molly and I am writing you because I would like to suggest a content piece for the Natural Building Blog. Building natural homes instead of using concrete is extremely important because we are running out of sand. The demand for sand has grown by 360% in the past 30 years and continues to do so, mostly due to the construction industry. By now, sand is the 2nd most extracted resource on Earth, over 40 billion tons are extracted every single year globally.