Copper has been used for 10,000 years, but 95% of it has been mined and smelted since 1900, and more than half has been mined in the last 24 years. Like many natural resources, the total reserves of copper in the earth are enormous (about 10,14 tons in the earth’s crust within one kilometer of the surface, which could be mined for five million years at the current rate. However, only a small portion of these reserves are economically viable to mine at current levels of technology and prices. Estimates of existing recoverable reserves range from 25 to 60 years, depending on assumptions about core indicators such as growth rates.[26] There is also a large portion of recoverable reserves that are now available. [26] A significant portion of copper is also now sourced from recycling. The future state of copper supply and demand is a controversial topic, involving a production peak similar to Hubbert’s Peak.
The price of copper has historically been very volatile, having risen six-fold since hitting $0.60 per pound ($1.32 per kilogram) in June 1999, rising to $3.75 per pound ($8.27 per kilogram) in May 2006, then dropping to $2.40 per pound ($5.29 per kilogram) in February 2007, and then bouncing back to $3.50 per pound ($7.71 per kilogram) in April the same year.[28] The price of copper is also now largely recycled. US$ per kilogram) In February 2009, weak global demand and falling commodity prices brought copper prices back down to US$1.51 per pound from their highs of a year earlier.
