Like Sam Clemens, I grew up along the Mississippi. Every few weeks we drove along windy, blue-brown expanses of river, barges, and rusty bridges to visit my grandma who lived across the river in Illinois. I took days off of high school to help fill sandbags during floods, so I remember how we stood on a hamlet Main St. watching the Illinois River flow at neck level just five feet away across a line of sandbags while a dark green Huey overhead scouted for levee leaks. Old white wooden houses loosened from foundations just 150 feet away, their rooftops visible in the muddy water. One night we worked by the Mississippi, passing sandbags to fill a sinkhole eroding half way up a levee, which, had it failed, would have ruined farms and grain elevators near Hannibal. It was eerie to stand in the dark watching the biggest man at the end of the line hurl sandbags into the hole, just yards away beneath a floodlamp. He had to stand close enough to toss a 60 pound bag into the hole but not so close that he’d be swallowed by quick mud.

The Mississippi was our ocean, changing color with passing clouds, churning brown when it rained, brimming wide and moving slowly. Standing on a wooded bluff or far out, barefoot on one of the shifting, sandy islands that formed along big bends, I figured the river was at least half a mile wide. Young Lincoln steered barges heaped with farmers’ goods downstream, where he no doubt witnessed the misery of floodplain slavery. He didn’t have to venture far---just a few hundred yards from the house where I grew up in south St. Louis County stood the ruins of an old farmhouse by a tiny pond and what was said to have been slave quarters.

Last July, I sat in a jet flying above the Ozarks to Charlotte. Years earlier, somewhere down below, a friend had died trying to jump from one eighty-foot rock column to another. Two Ozark lakes curved for over a hundred miles. And then I saw the Mississippi. Snaking off to the south, it defined the entire landscape. But as we got closer I couldn’t believe what I was seeing. Large stretches of river water were gone. In their place, roughly two-thirds of the riverbed was dry, empty stretches of pale mud and clay. Surely it’s just one section, I thought. The Mississippi never dwindled. But the spectacle ran for miles in both directions. The mighty Mississippi was drying up, and it may not be a single year’s drought. Scientists say global warming will reduce the region’s rains and bring higher temperatures, raising the question of whether millions of acres will continue to be arable. The sight below me was so unexpected that I couldn’t comprehend it. So, on my way to Spain, I just forgot about it – until I read that barge traffic on the lower Mississippi had to be halted for weeks because there wasn’t enough water for barges to pass. On July 3, the river was only 4.86 feet deep in Vicksburg.

The drought has continued. This week’s Guardian reports, “Barges are being sent off with lighter loads, making for more traffic, with more delays and back-ups. Stretches of the river are now reduced to one-way traffic.”

Meanwhile, Obama insists oil production is up, meaning decades more of internal combustion. Even if we were to stop using cars and coal-powered electricity today, CO2 levels wouldn’t dwindle for another 60 years. So, we’re left to wonder: if a mostly empty Mississippi is what we see now, at the shallow end of a what is almost certain to be years of global temperatures rising, just think what it will be like a few decades from now.
Yes, the Mississippi has sharp mood swings. During last year’s flooding its waters were 52 feet higher in Vicksburg.

However, in a decade when even George Bush Jr. conceded that we can expect to see mountain meadows disappear, the question is whether, during the worst of future droughts, Midwestern vegetables will be restricted to narrow, irrigated strips of land beside shrinking rivers, something like the Nile delta in Egypt. That would be a jolt – like the slowing of the Gulf Stream, or the melted lake at the North Pole. Or torrents of water called moraines that plunged into the Antarctic ice shelf before Connecticut sized sections broke off and drifted away. Like the disappearance of continental US glaciers, they, too, are disturbing benchmarks that were once thought impossible.