Our global population of 7 billion has been steadily expanding and it's only going to grow faster as the century continues. But what will a world with 11 billion people look like? Paul Hanley has a written a book on the subject and he's here to answer our questions.

Hanley is an environmental writer and the author of Eleven, a new book which looks at what we might expect if UN projections that predict our population will reach 11 billion by 2100 hold true.

He'll be joining us from 11 A.M. - noon today, so start asking him your questions now. He'll be answering as many as he can while he's here.

Image: Global population density / Anders Sandberg