Sustainable Building and Construction - International Environmental ...

Sustainable Building and Construction
(* further explanation and source: Greenhouse Gas Division Environment Canada,
June 2002, available at: http://www.ec.gc.ca/pdb/ghg/1990_00_report/sec1_e.cfm)
According to the IPCC (Intergovernmental Panel on Climate Change, 2001, available
at the world-wide-web: http://www.ipcc.ch/) some of the expected impacts of the
increased concentrations of GHGs on the climate system include:
- Increasing extremes of drying and heavy rainfall and increases in the risk of
droughts and floods that occur with El Niño events in many different regions;
- Sea level rise, through thermal expansion of seawater and widespread loss of
land ice. Global mean sea level is projected to rise by 0.09-0.88 m between
1990 and 2100, for the full range of scenarios examined. This is due primarily
to thermal expansion and loss of mass from glaciers and ice caps; ice sheets
will continue to react to climate warming and contribute to sea level rise for
thousands of years after climate has been stabilized;
- Weakening of the ocean thermohaline circulation (THC, Large-scale densitydriven
circulation in the ocean, caused by differences in temperature and
salinity. In the North Atlantic, the thermohaline circulation consists of warm
surface water flowing northward and cold deepwater flowing southward,
resulting in a net pole ward transport of heat. The surface water sinks in highly
restricted sinking regions located in high latitudes which leads to a reduction
of the heat transfer into high latitudes of the Northern Hemisphere; and more
rapid warming of land areas than the global average, particularly those at
northern high latitudes in the cold season. Most notable of these is the
warming in the northern regions of North America.
(Summary from Greenhouse Gas Division Environment Canada, June 2002,
available at: http://www.ec.gc.ca/pdb/ghg/1990_00_report/sec1_e.cfm)
Examples of impacts resulting from projected changes in extreme climate events are
available at the website “Climate Change 2001: Working Group II: Impacts,
Adaptation and Vulnerability; 2.6. The Potential for Large-Scale and Possibly
Irreversible Impacts Poses Risks that have yet to be Reliably Quantified”
(http://www.grida.no/climate/ipcc_tar/wg2/009.htm#tabspm1)
Illustration 5: The Earth’s
annual and global mean energy
balance. Of the incoming solar
radiation, 49% (168 Wm-2) is
absorbed by the surface. That
heat is returned to the
atmosphere as sensible heat, as
evapotranspiration (latent heat)
and as thermal infrared radiation.
Most of this radiation is
absorbed by the atmosphere,
which in turn emits radiation
both up and down. The radiation
lost to space comes from cloud
tops and atmospheric regions
much colder than the surface.
This causes a greenhouse effect.
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