Bill McKibben is perhaps one the most recognized defenders of our planet and chronicler of how we could better inhabit it. Twenty years ago, with his book, The End of Nature, Bill McKibben offered one of the earliest warnings about global warming. Those warnings went mostly unheeded. His latest book, Eaarth: Making a Life on a Tough New Planet, is his latest plea for each of us to consider deeply how we tread upon this earth. Whether you are a person of faith, a gardener, or both, youâ€™ll find a clear message of action, hope, and urgency in this Arnold Arboretum presentation on Thursday, April 7, beginning at 7 pm at Trinity Church, Copley Square, 206 Clarendon Street, offered with Trinity Church as part of Trinity’s Gardens and Spirit Lecture Series. Fee: $25 nonmember.Â To register, log on to www.arboretum.harvard.edu, or you may purchase tickets at the Trinity Bookstore.