Introduction - Climate Change Impacts on Freshwater Ecosystems - page 12

Projected impacts of climate change
Global temperature change (relative to pre-industrial)

0 C 1 C 2 C 3 C 4 C 5 C

Food Falling crop yields in many areas, particularly

developing regions
Possible rising yields in
some high latitude regions

Falling yields in many
developed regions

Significant decreases in water
availability in many areas, including
Mediterranean and southern Africa

Water

Small mountain glaciers
disappear - water
supplies threatened in
several areas

Sea level rise
threatens major cities

Ecosystems

Extensive damage
to coral reefs

Rising number of species face extinction

Extreme
weather
events
Risk of abrupt and
major irreversible
changes

Rising intensity of storms, forest fires, droughts, flooding and heat waves

Increasing risk of dangerous feedbacks and
abrupt, large-scale shifts in the climate system

Figure 1.5 Projected effects of increasing temperatures on natural and human
systems. (From Stern 2006.)

cost of a substantial but affordable sum, if there were reaction now, but much
greater sums if there were delays. Governments have attempted to put in place
mechanisms to generate energy by means other than burning fossil fuels, devices
to encourage energy conservation and schemes to offset carbon usage by paying
for trees to be planted. By and large none of these schemes has yet reduced
fossil fuel consumption (Monbiot 2007) and it seems very likely that temperatures
will rise later this century by several degrees. A 2°C rise may be held at a
concentration of greenhouse gases equivalent to about 480 ppm carbon dioxide
compared with the current value of 380 ppm carbon dioxide. It seems, however,
more likely that concentrations will rise to at least 550 ppm, denoting a
temperature rise of 3°C-4°C, which will bring many problems (Fig. 1.5). The
possibilities of biological feedback mechanisms have not, of course, been factored
into any of these targets.
A glance through any daily newspaper will reveal several pages of business and
sports news that change in detail but not overall content. Pages of other news will
change in scope more than business and sport and increasingly a consistent though
still very small element of these will concern environmental issues. We might
anticipate a time, however, when this formula will change. Sport will undoubtedly
retain its hegemony, but the unfolding impacts of resource depletion, waste
accumulation, ecosystem destruction, population increase and climate change must
eventually displace the multi-page minutiae of stocks, shares, executive salaries and
the fate of companies. A new economics will need to be in place or we may be