CleanBeta

What to Expect When You’re Expecting Climate Change: Salty Water & Thirsty Mouths

Estimates of ocean heat content and sea surface temperature

Top graph: Comparison of our upper-ocean heat content with previous estimates (red1 and blue12) for the upper 700 m. The straight lines are linear fits to the estimates. The global mean stratospheric optical depth(arbitrary scale) at the bottom indicates the timing of major volcanic eruptions. The brown curve is a three-year running average of these values, included for comparison with the smoothed observations.

Bottom graph: Comparison of thick black line, as in a with the thick red line; (thin red lines indicate estimates of one standard deviation error) results with sea surface temperature (blue; right-hand scale). All time series were smoothed with a three-year running average and are relative to 1961.

The Central Intelligence Agency has added water to the list of resources in country profile’s included in the Agency’s annual publication, the CIA World Factbook. The strategic significance of clean water is hardly a national secret, but it might as well be considering the paucity of people who appreciate its fully. I am not entirely innocent on that point, but I’m trying hard to change that. Ergo: what’s happening to our water? The simple and shocking answer is its heating up . . . and faster than anyone thought.

Climate change is the culprit and its running roughshod over the world’s water supply. The oceans hold over 90% of heat in the world’s climate system and act as a temporary buffer against the effects of climate change. Scientists at Lawrence Livermore National Laboratory recently discovered that the ocean is warming 50% faster than previous estimates, including those in the 2007 Intergovernmental Panel on Climate Change report.

Granular increases in global temperatures have enormous influence on every aspect of global ecology. For instance, the frequency and intensity of algal blooms in the ocean have escalated in the past two decades. These algal blooms decimate marine life across broad swaths of ocean. The dead zone in the Gulf of Mexico has decimated marine life. In a single decade, it has ballooned in size as the Mississippi dumps more and more nutrient packed fertilizer into it every year. Why now? Heat. Left unchecked, global warming will increase the amount of water discharged from rivers by almost 15%.

Water is considered potable if it has less than 250 milligrams of salt per liter. Brackish water exceeds this salinity threshold and so is too salty to drink. On the other hand, brackish water is not salty enough to be considered salt water. As climate change accelerates, new research shows that a zone of brackish water will creep over surface and ground water, increasing salinity and reducing the amount of available fresh water. Below is a map of increased salinity in U.S. aquifers:

Salt Intrusion in U.S. Aquifers

The shaded area’s in the map above indicates undue salinity. Salt has seeped into aquifers and well water in the coastal areas of the United States where underground saline water penetrates further inland than surface water does. When water is pumped out of the fresh water aquifers, the underlaying salt water is drawn up into the fresh water zone.

The shaded areas in the second map (below) indicates high salinity in U.S. water supply — whether from aquifer intrusion or ground water contamination.

Salt in U.S. Water Supplies

Of course, salinity is hardly the only worry the world should have with fresh water supplies. Plain vanilla depletion is troubling too. The shaded areas in the map below indicate water depletion in U.S. aquifers.

Water Depletion in the United States

The American southwest will grow increasingly arid over the next century. As the subtropical dry zone reaches further toward the poles. Over the next century, temperatures in the West will rise 4–9°F (2–5° C).