THE NATURAL MOMENT 



UP FRONT 



■< See preceding two pages 



the Camargue, swatting mosquitoes 

 while he waited for a riderless caval- 

 ry to storm his camera. And, action! 

 A local farmer herded a group of 

 free-roaming horses toward Bloom. 

 A few splashes later, the horses — 

 icons of the Camargue — whooshed 

 past, leaving Bloom to shake the 

 water out of his trusty camera, now 

 in need of repair. 



Bloom and other naturalists have 

 long been enchanted with the breed 

 of horses living in the Camargue, the 

 triangular delta in southern France 

 where the Rhone River meets the 

 Mediterranean Sea. The horses — 

 which, at a height of only thirteen 

 or fourteen hands, actually qualify as 

 ponies — have lived there for at least 

 2,500 years. They share the marsh- 

 lands with millions of migratory 

 birds, not to mention a growing 

 population of human beings. 



Easily observed, yet generally un- 

 constrained, Camargue horses have 

 been a boon to scientists studying 

 their behavior and environment for 

 several decades. Unfortunately, 

 though, their most recent scientific 

 contribution has been to serve as an 

 unwitting test bed for the spread of 

 West Nile virus. First infected in the 

 early 1960s, the Camargue popula- 

 tion suffered a second outbreak in 

 2000, when twenty-one horses 

 died. The episode sparked a contro- 

 versy about insect control — and hu- 

 man intervention. 



Now the coastal sanctuary may be 

 facing another invasion: the H5N1 

 avian flu virus. Camargue watchers 

 like Steve Bloom will keep monitor- 

 ing the wildlife, and weighing the 

 need to intervene. — Erin Espelie 



Playing with Fire 



Anyone paying attention to the news knows that many of the 

 world's flashpoints — the war in Iraq, the politics of the Mid- 

 dle East, terrorism and its consequences — have grown large- 

 ly out of just one issue: energy. Of course, every major effort to har- 

 ness energy since the control of fire has come with serious drawbacks. 

 But fossil fuels now pose a global problem that probably transcends 

 even war, politics, and terrorism: the threat of global warming. 



When fossil fuels burn, they release carbon dioxide (C0 2 ), a gas 

 that contributes to the atmospheric greenhouse effect of trapping 

 solar heat at the Earths surface. And of all fossil fuels, by far the big- 

 gest troublemaker for the climate is coal. As Jeff Goodell points out 

 ("Cooking the Climate with Coal," page 36), for every kilowatt-hour 

 of usable energy from coal, 2.1 pounds of C0 2 are pumped into the 

 atmosphere. (The same energy from oil releases 1.4 pounds of C0 2 ; 

 from natural gas, 0.8 pound.) Yet new coal-fired power plants ex- 

 pected to be built in the next twenty-five years would add more than 

 1,350 gigawatts to the present generating capacity. If those plants are 

 built, Goodell notes, they will produce more C0 2 in their sixty-year 

 operating lives than all the coal burned in the past 250 years. 



• • • 



But so what? If sea levels rise, can't we simply move back from 

 the shore? If the heat becomes uncomfortable, can't we just shift 

 farther from the equator? Elizabeth Kolbert's new book, Field Notes 

 from a Catastrophe, reviewed in this issue by Laurence A. Marschall 

 ("Bookshelf," page 58), describes why some of the changes may not 

 be so easy to swallow. Warmer temperatures are expected to drive 

 more intense storms. Displacement of ecosystems may stir up deadly 

 strains of bacteria or viruses. Warmer temperatures may also trigger 

 effects that could snowball unpredictably. The Greenland ice cap — a 

 big snowball if there ever was one — is slipping toward the sea, and 

 the slippage is accelerating, perhaps because meltwater is lubricating 

 the base of the ice. Organic matter in Arctic permafrost is only partly 

 decayed; as it thaws, decay recommences and more carbon enters the 

 atmosphere, thawing the permafrost even more. In "Gas Trap" (page 

 62) Robert Anderson describes what may be the scariest snowball 

 scenario of all: Methane, a greenhouse gas twenty times more potent 

 than carbon dioxide, is also locked up in the permafrost. So melting 

 permafrost could also release methane into the atmosphere, further 

 accelerating the warming trend. 



There is some middling-good news, though. As Stephan Reebs 

 reports ("Sink in the Sea," page 12), scientists have recently discov- 

 ered two "sinks" for carbon whose importance had been underesti- 

 mated: krill convey organic matter to the seafloor, and mangroves, 

 when they decay, inject dissolved organic matter into the oceans. 

 Unfortunately, mangrove forests are declining worldwide. 



• • • 



Neil deGrasse Tyson is taking a break from his "Universe" col- 

 umn this month. He'll be back next month. — PETER BROWN 



6 



NATURAL HISTORY May 2006 



