Washington Post: I have devoted many columns to sustainability issues in terms of a single house. But every so often I like to pull back for the truly wide shot. From a global perspective, what is the state of our planet, and how might this affect our housing choices? There is no better place to get a sense of this than the book "Plan B 3.0: Mobilizing to Save Civilization" by environmentalist Lester R. Brown. His ability to make a complicated subject accessible to the general reader is …