Beyond the immediate human toll, disasters destroy hundreds of thousands of buildings each year. In 2013, Typhoon Haiyan damaged a record 1.2 million structures in Philippines. Last year, earthquakes and cyclones damaged more than half a million buildings worldwide. For communities to rebuild their lives, these structures must be rebuilt.

For instance, an estimated one billion burnt clay bricks were needed to reconstruct the half-million homes destroyed in the Nepal earthquake. This is enough bricks to circle the Earth six times if laid end to end. How can we responsibly source such vast quantities of materials to meet demand?

Id suggest we’ve never been concerned about "responsibly sourced " in the past so we’re unlikely to worry to much in that regard. Examples of that irresponsibility be Oil, Gas, Gold, Coal, Sand etc