LIVING beside North America’s greatest river is inevitably going to be fraught at times. This week, many residents along the Mississippi are counting the cost of the worst floods on record. As New Scientist went to press, Baton Rouge and New Orleans seems to have dodged a bullet, but people in the Atchafalaya basin will join those around Yazoo City and Vicksburg in cursing Ol’ Man River.
Yet the short-term tragedy of flood victims could have a long-term benefit by hastening a restoration plan for one of the Mississippi’s biggest losers – its delta (see page 6).
Today’s Mississippi is a largely human creation – dammed, diverted, dredged and constrained by concrete. By channelling the main flow, the vast volumes of sediment that used to be
deposited across the delta now travel out to sea. The result is coastal erosion, which threatens the natural environment and makes low-lying settlements even more vulnerable to storm surges from the south.
This pattern is being repeated across the world. According to James Syvitski, a sedimentologist
at the University of Colorado, Boulder, it is now virtually impossible to find a river system that has not been replumbed by humans.
China’s Yellow river, for example, used to meander over a flood plain 700 kilometres wide. It is now corralled into a single
channel. In places the river resembles an aqueduct rising 10 metres or more above the surrounding countryside.
Changed sedimentation rates, subsidence caused by extraction of oil, gas and groundwater, and compaction caused by cities have pushed large areas of many of the world’s deltas below sea level. Among the worst affected are the Nile, Yellow, Ganges, Indus and Mekong deltas. Millions of people who live on and around them grow more insecure by the day.
Enlightened policies to restore sediment flow to the wetlands may yet save the Mississippi delta. Some people will lose out, but the consequences of inaction will be worse. If the Mississippi project is successful, it will create a model for other countries. Deltas are too precious to people and the natural world to let them be destroyed. n
When humans try to constrain rivers, the results can be calamitous
JEAN-DOMINIQUE BAUBY famously wrote his memoir The Diving Bell and the Butterfly with painstaking blinks of his left eye – the only part of his body over which he had any control. On page 40 we report on a technique that could allow other locked-in people to communicate more naturally, by directly translating their thoughts into words.
This stunning research is mainly aimed at liberating minds trapped in broken bodies, but it could also blow the lid off one of the oldest questions in linguistics and philosophy: what is the relationship between language and thought? Does our native language influence how we think, or is the essence of thought the same for us all? The debate has run for decades and,
because it was largely untestable, it has been a matter on which smart people must agree to disagree.
The new work may finally deliver an answer by offering access to the neurological essence of thought before it is converted into speech. It may even be a step on the road to a universal translation device.
Concerns will inevitably be raised about “mind-reading” and privacy. But in light of the benefits, the risks are worth taking. Let the mind-reading begin. n
The essence of thought
“It is now virtually impossible to find a river system that has not been replumbed by humans”
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MOVIE special effects have been blurring the line between the virtual and the real for decades. Today, audiences routinely see things that would be impossible to create without computers –
with one important exception. If you want lifelike characters you still need to use real actors.
Now advances in special effects mean that it will soon be impossible to tell the difference between real actors and their digital doubles (see page 20). We could even see entirely virtual actors winning Oscars.
Purists won’t like the idea. But as with all cinematic technology, it is a means to an end. Special effects alone don’t make a great movie: virtues such as gripping scriptwriting and storytelling will still carry the day. To film-makers the virtual actor will open up new possibilities for delivering their art. Now that’s entertainment. n