Geoscience Reference
In-Depth Information
period of decades and more, allowing natural processes to shift the
beaches, ponds, and dunes will protect the overall value of land and
ecosystems better than a Maginot Line mentality of protecting every
parcel. This is yet another example of the value of migration—of peo-
ple, of capital, and in this case of sand and ecosystems—in reducing the
long-run costs of climate change.
OCEAN ACIDIFICATION
One of the themes of our survey of climate-change impacts is that
the most troubling issues involve unmanaged or unmanageable sys-
tems. From an ecological perspective, humans are increasingly manag-
ing their environment. Over the last millennia, we have cleared fi elds
and forests, moved from caves to houses, centralized exchange of goods
in markets, and introduced technologies to control our personal and
industrial climates.
But some areas are diffi cult or impossible to control. According to
legend, King Canute found that when he commanded the tides to halt,
they did not obey his order. In the modern era, we can build dikes and
seawalls, but the ocean continues to rise around them. We will see
similar issues in this chapter's review of acidifi cation as well as in the
next two chapters' analyses of hurricanes and species loss.
In each of these unintended consequences of human activity, we
can echo King Canute's lament, “Let all men know how empty and
worthless is the power of kings, for there is none worthy of the name
but God, whose eternal laws heaven, earth, and sea obey.” This will be
the cry of future generations if we do not take forceful steps to reverse
the rising tide of CO
2
and other greenhouse gases.
CARBONIZATION AND ACIDIFICATION
Another particularly unmanageable consequence of rising CO
2
con-
centrations is the carbonization and acidifi cation of the oceans. Here,
the issue is quite distinct from global warming because the problem does
not result primarily from warming but from the carbon itself. Rising
CO
2
concentrations in the atmosphere are quickly mixed into the upper
layer of the oceans. While the transport of the carbon into the ocean
