Geoscience Reference
In-Depth Information
Figure 10-14.
Modern oil-shale power plant produces electricity and hot water near Narva, northeastern Estonia.
Fly ash is captured by dust i lters, and pipelines in the foreground carry l y-ash slurry to holding ponds. Processed
l y ash is sold for various construction, agricultural, and industrial applications. Photo courtesy of E. Karofeld.
comfort rather than the greater good of society
or long-term environmental sustainability.
The greatest impacts of this human experi-
ment on wetlands involve the carbon and nitro-
gen cycles as well as biodiversity. In all three,
results of human activities have already exceeded
so-called boundary limits, beyond which conse-
quences are uncertain or perhaps irreversible
(see Preface, Table 1). Other major biogeochem-
ical impacts on wetlands include land conver-
sion, water consumption, phosphorus loading,
ocean acidii cation, and chemical pollution. For
many people, wetlands are still regarded as
wastelands, and for the majority of humanity
daily survival has a much higher priority than
protecting natural resources for a distant future.
Meanwhile, citizens of developed countries are
unlikely to give up their relatively rich lifestyles,
residents of developing countries will seek to
achieve the living standards of richer countries,
and global population will continue to grow,
perhaps reaching a peak around 10 billion
people late in this century (Lutz, Sanderson and
Scherbov 2001). Given this point of view, human
encroachment, alteration, and destruction of
wetlands is likely to continue, particularly in
developing and poorly developed countries.
The human experiment has been costly for
environmental resources in general and wetland
habitats in particular. Nonetheless, the conserva-
tive nature of wetland l ora and fauna gives
them the capacity to survive under adverse con-
ditions, as happened during previous extinction
events (Greb, DiMichele and Gastaldo 2006). As
the Estonian oil-shale example demonstrates,
many wetlands still retain the ability for internal
self-renewal once external disruptions are
reduced or removed. A central problem facing
wetland maintenance and restoration for the
twenty-i rst century, then, is how to reduce
human environmental impacts, particularly for
the carbon and nitrogen cycles. The human
factor for both cycles derives in large part from
massive use of fossil fuels, which are burned for
energy and processed for fertilizer.
Before assigning any blame for greenhouse
gases, however, it would be wise to consider
the question: who is responsible for carbon
