The Missing Greenhouse Gas - The Ripple Effect: The Fate of Freshwater in the Twenty-First Century - page 77

CHAPTER 8
The Missing Greenhouse Gas
A BIGGER PROBLEM THAN CARBON
“By the way, dead zones aren't just a local syndrome,” Bob Hirsch said on our last day of
touring the Chesapeake Bay watershed. “You see it in much bigger river systems, like the
Mississippi and Atchafalaya. It's a global problem—a growingglobal problem.”
In 2004, the UN reported 146 dead zones worldwide . By 2008 there were 405. hese
areas affected a total of more than 245,000 square kilometers, which is roughly the size
of the United Kingdom. They are found in the Baltic Sea (now hypoxic year-round), the
Black Sea, the Adriatic, and of the coasts of South America, Japan, Australia, and the Un-
ited States. They can appear in the salt water of Long Island Sound and the freshwater of
Lake Champlain—both popular recreation areas where water quality has been seriously
degraded. The dimensions of dead zones change over time, according to wind, weather,
and nutrient flows. Some are small, perhaps one square kilometer, while others, such as
the persistent dead zone of the coast of Oregon , measure three hundred square miles.
“We believe that nitrogen is the main problem,” said Hirsch, who is frustrated by the
lack of research on the subject. “A lot of people are focused on CO 2 these days—we hear
about carbon emissions, carbon footprints, carbon trading, carbon caps, carbon sequest-
ration, you name it—which is all well and good, don't get me wrong. But when it comes
to discussing big environmental issues, carbon tends to 'suck all of the oxygen out of the
room.' There's little discussion of other issues, like nitrogen—which is arguably an even
bigger problem than carbon.”
Some scientists have labeled nitrogen a “missing greenhouse gas” because it is not
one of the four gases (carbon dioxide, methane, nitrous oxide, and sulfur hexafluoride)
and two groups of gases (hydrofluorocarbons and perfluorocarbons) named in the Kyoto
Protocol, the global accord on climate change.
Mankind is changing the way certain elements move around between soil, rock, living
things, water, and air. We have caused the most significant changes by our heavy reliance
on nitrogen and carbon. “In our focus on climate change, driven mostly by carbon, we
shouldn't lose sight of the way we are changing the nitrogen cycle,” Hirsch said. “In fact,
while carbon in the atmosphere has increased by about thirty-five percent over the past
century, nitrogen flowing down the Mississippi River has increased two hundred per-
cent.”