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.