# Levels of contamination in water are rising, as water proceeds through the [[water cycle]] it becomes progressively more contaminated. If earth (and life) had existed for billions of years, a limit would have long been reached where water (essential to life) was too contaminated for life to continue. | # Levels of contamination in water are rising, as water proceeds through the [[water cycle]] it becomes progressively more contaminated. If earth (and life) had existed for billions of years, a limit would have long been reached where water (essential to life) was too contaminated for life to continue. |