Hot summer of 2003 inhibited plant growth
The above-average summer of 2003 in Europe not only led to a sharp increase in forest and bush fires, but also reduced plant growth in the affected regions by around thirty percent.
According to the findings of a group of scientists led by Philippe Ciais from the Laboratory for Climate and Environmental Sciences in-g.webp" />2, as the researchers analyze from their data collected across Europe. The drop in net primary production was triggered by water shortages and extreme heat, and was particularly severe in central European beech stands and northern Mediterranean forests, but all other locations were also affected. In agriculture, major crop failures were reported in France and Italy in particular due to the heat, and in Romania and the Ukraine due to drought.
In addition, the respiratory activity of plants and thus the oxygen consumption of entire ecosystems decreased, which contrasts with previous findings, according to which rising temperatures increase the need for oxygen. However, the dry soil and lack of nutrients also impeded the metabolism of soil microbes and plants, which is why they released an average of 77 grams less carbon per square meter on the test areas. However, because the plants' carbon uptake was also reduced by 195 grams per square meter, more CO2 was released into the atmosphere, which more than offset the net storage of the greenhouse gas from the previous four years.
Using model calculations - based on historical records of crop yields - the scientists conclude that such a loss of primary crop production has not occurred in Europe for at least the last century. They also fear a long-term change in the continent's carbon cycle, as more frequent droughts and hot spells more than offset apparent positive changes in climate change, such as longer growing seasons.
