Yesterday, my drive from Columbia to Cincinnati crossed soggy terrain. Rivers and streams were out of their banks, crop fields were muddy (if not swamped) and sloughs along the highway were filled to the brim. Overhead, thick gray clouds, pregnant with moisture, dropped curtains of rain across the verdant landscape. While the flooding is a bit late this year, spring is the season of rebirth and water is the blood of all life on Earth.
Indeed, life evolved in Earth's primordial seas some 3.6 billion years ago, nourished by the effluent of surface streams and deep hydrothermal vents. Those initial cells and the cells of all bacteria, fungi, plants and animals throughout our plant's history have been dependent on the availability of water, a medium vital to the biochemical processes that sustain life.
Though water covers more than 70% of our planet's surface, only 3% of the water on Earth is freshwater; of that small amount, almost two-thirds is trapped within polar and mountain ice sheets and permanent snow fields (the great majority of which is on Antarctica). About half of liquid freshwater is in the form of groundwater while the combined freshwater in lakes and rivers accounts for only 0.5% of the water on Earth. While spring floods may be inconvenient and, in some cases, destructive, the above facts demonstrate how vital they are to the health of natural ecosystems and, by extension, to the welfare of human society. We cannot afford to waste or pollute what little freshwater is available.
