Climate Change Threatens Siberian Forests
- Climate Change Threatens Siberian Forests
Leicester UK (SPX) Aug 01, 2007
In Central Siberia alone, fires have destroyed 38 000 km2 in the extreme
fire year of 2003. In that year the smoke plumes were so huge that they
caused air pollution as far as in the United States. An international
team of scientists believes that Siberian fires are influenced by climate
change. The study was led by the Professor Heiko Balzter of the
Department of Geography at the University of Leicester.
Professor Balzter said "Last century a typical forest in Siberia had
about 100 years after a fire to recover before it burned again. But new
observations by Russian scientist Dr Kharuk have shown that fire now
returns more frequently, about every 65 years. At the same time annual
temperatures in Siberia have risen by almost two degrees Celsius, about
twice as fast as the global average. And since 1990 the warming of
Siberia has become even faster than before."
Global warming leads to warmer springs and causes plants to green up
earlier. This has already been observed for the UK. Over Russia the
scientists found similar trends towards an earlier spring.
The scientists observed 18 years of satellite images of the region, and
estimated the timing of the onset and end of the growing season, when the
snow has melted and the plants take up carbon from the air during plant
growth. From 1982 to 1999 almost all Siberian ecosystems showed an
earlier onset of spring. The strongest advance of spring was observed in
Urban areas (0.74 days advance per year), Deciduous Broadleaf Forest
(0.46 d/a), Forest - Cropland complexes (0.62 d/a), Humid grasslands
(0.35 d/a) and Cropland - Grassland complexes (0.45 d/a).
"Central Siberia has a more continental climate. The changes in the
timing of spring and also in fire occurrence are linked to temperature
changes and a climate pattern that scientists call the Arctic
Oscillation" said Professor Balzter. "Towards the East Siberian coast the
Pacific plays a more important role, and the El Nino phenomenon together
with low rainfall determines what happens to the forest".
In the continental parts of Central Siberia the Arctic Oscillation and
corresponding heat waves are thought to control the fire regime, while in
East Siberia El Nino conditions and droughts are thought to play a major
"Planet Earth is always more complicated than you think", says Professor
Balzter, "The lengthening of the growing season that has been described
in the scientific literature is a non-linear phenomenon. It is influenced
by feedbacks between the atmosphere and the forest, which responds to
rising greenhouse gas levels and higher temperatures."