Despite the disparate arenas of study and practice, the principles of spiritual ecology are simple: In order to resolve such environmental issues as depletion of species, global warming, and over-consumption, humanity must examine and reassess our underlying attitudes and beliefs about the earth, and our spiritual responsibilities toward the planet.[3] U.S. Advisor on climate change, James Gustave Speth, said: "I used to think that top environmental problems were biodiversity loss, ecosystem collapse and climate change. I thought that thirty years of good science could address these problems. I was wrong.