Because after we use iron, aluminum, and NaCl, they are still iron, aluminum, and NaCl. our using them doesn't prevent future generations from using them. Peak

Because after we use iron, aluminum, and NaCl, they are still iron, aluminum, and NaCl. our using them doesn't prevent future generations from using them. Peak concrete is also sound economics, it just gets less air time because there are more alternatives and fewer affected industries.