While anti-border wall activists see a coming eco-apocalypse, some border-wall proponents already see one caused by unchecked illegal immigration. The problems linked to illegal immigration have had much attention lately: the criminals and potential terrorists entering without permission, the young children needing care and workers taking jobs that Americans, in fact, would do. Then there’s the burden on taxpayers for all the social services as well as the possibility that lax state laws let them vote. Now a new one has begun getting attention: the millions of pounds of garbage left by those traveling through southwest America’s deserts illegally. “Perhaps...