| CANBERRA,
AUSTRALIA, May 09, 2005, Cooperative Research Centre
for Greenhouse Accounting: Climate change is
already affecting the growth of plants, the productivity
of farms, and habitats for animals, according to a Communiqué
from a meeting of about 80 research scientists from
across Australia.
The scientists, members of the Cooperative Research
Center for Greenhouse Accounting, issued the Communiqué
from their 2005 Annual Science Meeting.
"Atmospheric temperatures are increasing, oceans
are becoming warmer, sea levels are rising, rainfall
patterns are changing. The amount of sunlight reaching
the earth's surface directly is falling, as are evaporation
rates from land-based water bodies and potential evaporation
rates from the soil and vegetation," they said.
Releasing the Communiqué, CRC for Greenhouse
Accounting Chief Executive Dr Michael Robinson stressed
both the urgent need for action to address global climate
change, and the scale of actions required. "Even
50 percent reductions in global emissions of greenhouse
gases would see carbon dioxide levels in the atmosphere
rise to about three times their natural levels,"
he said. "Over the past six years the Cooperative
Research Center for Greenhouse Accounting has made significant
advances in developing our understanding of how forests,
farms, grasslands and woodlands can play a part in the
battle to limit climate change and its impacts."
In their Communiqué, the scientists said sustainably
managed forests, farms and grasslands had the capacity
to ameliorate climate change by storing more carbon
in soils, plant material and wood products, effectively
removing significant amounts of the major greenhouse
gas carbon dioxide from the atmosphere.
But they warned that water, nutrient and temperature
stresses common in Australia and global dimming - the
widely observed decrease in direct sunlight arriving
at the earth's surface over recent decades - could inhibit
the enhanced plant growth which might otherwise have
been expected from increasing concentrations of carbon
dioxide in the atmosphere.
As a result, plants could act as a positive feedback
mechanism, exacerbating rather then ameliorating the
changes in climate.
"Likewise, if climate change increases the frequency
and extent of fire in Australia, some of the large quantities
of carbon stored in vegetation and soil will be released
to the atmosphere in the form of greenhouse gases,"
they said.
They said that while scientific knowledge was much
improved, many uncertainties remained and continued
research was vital. " While we have identified
some plant responses to atmospheric and climate changes,
our understanding of underlying causes is far from complete.
The cause of global dimming and its future course remain
subject to scientific debate. Further fundamental research
is required if we are to reduce the many uncertainties
in our understanding of how plants and soils will respond
to continuing increases in the concentrations of greenhouse
gases in the atmosphere and the resulting changes in
climate," the Communiqué said.
"Understanding of plants' interaction with climate
change is central to sustainable management of our landscapes,
productivity of our farms, and in the battle to minimise
adverse impacts from our emissions of greenhouse gases."
The text of the Communiqué can be found at www.greenhouse.crc.org.au/crc/ecarbon/communique_050508.cfm.
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