We do not know how much of the environmental change is due to human activities and how much [is due] to long-term natural processes over which we have no control.
Freeman J. Dyson (2007). “A Many-colored Glass: Reflections on the Place of Life in the Universe”, p.29, University of Virginia Press
![We do not know how much of the environmental change is due to human activities and how much [is due] to long-term natural processes over which we have no control.](http://cdn.quoteddaily.com/images/freeman-dyson/we-do-not-know-how-much-of-the-environmental-change-is-due-to-human-activities-and-how-much-is-due.jpg)