November 30, 2005

Climate change in Europe

The vulnerability of several European regions to global environmental change will increase during coming decades, creating problems for agriculture, forestry, nature conservation, energy, water and tourism. This is a consequence of both climate change and changing land use. Together, these changes reduce the ability of ecosystems to deliver the 'services' human society needs, such as food, water and recreation. Particular at risk are the Mediterranean and mountain regions. These are the main conclusions of a new study, published in 'Science' this week.
Thus starts a press release by the authors of the Science study. The abstract of the original study is less gloomy:
To investigate ecosystem service supply during the 21st century, we used a range of ecosystem models and scenarios of climate and land-use change to conduct a Europe-wide assessment. Large changes in climate and land use typically resulted in large changes in ecosystem service supply. Some of these trends may be positive (for example, increases in forest area and productivity) or offer opportunities (for example, "surplus land" for agricultural extensification and bioenergy production). However, many changes increase vulnerability as a result of a decreasing supply of ecosystem services (for example, declining soil fertility, declining water availability, increasing risk of forest fires), especially in the Mediterranean and mountain regions.
The differences between the two accounts of the same study by the same authors are interesting in their own right, but I will not dwell on that.

According to the study, Mediterranean and mountain regions will experience more drastic changes in the geographic distribution of species. Given the limited ability of species to shift their ranges, partly due to the fact that agricultural lands and towns act as barriers to dispersal, many species will have reduced geographic ranges. As a result, the study cites "implications for the sense of place and cultural identity of the inhabitants, traditional forms of land use, and the tourism sector."

Additionally, mountain regions will have less snow cover:
Case studies for the Rhine, Rhône, and Danube basins, as well as for small Alpine catchments, indicated climate-induced changes in the timing of runoff. These result from impacts of rising temperatures on snow-cover dynamics, which enhanced winter runoff, reduced summer runoff, and shifted monthly peak flows by up to two months earlier than at present. This reduced water supply at peak demand times and increased the risk of winter floods. Changes in snow-cover dynamics directly affect biodiversity at high elevations. Moreover, navigation and hydropower potential would be altered.

In addition to its importance for water supply and biodiversity conservation, snow cover is of course indispensable for winter tourism. The Alpine case studies indicated a rise in the elevation of reliable snow cover from about 1300 m today to 1500 to 1750 m at the end of the 21st century. A 300-m rise of the snow line would reduce the proportion of Swiss ski areas with sufficient snow from currently about 85 to 63%. [I have deleted the references to tables and other studies.]
It seems to me that less snow cover would also have some benefits for the people who live in those places, but the authors do not mention them. Anyway, I think the enjoyment of higher temperatures across Europe more than offsets the predicament of skiers.

Regarding the Mediterranean, "[t]he impacts included water shortages, increased risk of forest fires, northward shifts in the distribution of typical tree species, and losses of agricultural potential." Problems of water shortages, forest fires and agriculture in Mediterranean Europe have mainly political, not environmental, causes. Water shortages are due to government subsidies to consumption, especially in agriculture. Humans intentionally cause almost all forest fires in the region. In Spain, the regions most affected by fires are those with the wettest climate. There (here, from my geographical point of view), unwanted fires result from a combination of bizarre government subsidies and loose property rights of the land. Finally, Mediterranean agriculture depends on government subsidies and has little to do with environmental or market factors. Water shortages, fires and agriculture in Mediterranean Europe are government "services;" they have little to do with ecosystem services.

In the end, if we circumscribe the question to Europe, I am left worried only about the effects of climate change on wild nature. Given European institutions, those of us who love nature stand to loose from rapid climate change. To preserve wild habitats and species in a rapidly changing Europe we need rapid responses. We need flexibility. Static nature reserves will not help. Huge public works that act as huge and irreversible ecological barriers will not help. Kafkaesque bureaucracy will not help.

1 comment:

  1. Good post. An excerpt:

    "One thing is certain, any change in the global weather system, whether it is a cooling or warming trend, and whether it is caused by us or not, will have a devastating effect on what is left of our natural ecosystems, as they are so severely stressed by humanity already. For example, if the forest habitat of the mountain gorilla shrinks because of a lack of rain, that will be the end of mountain gorillas. In the past, pockets of habitat would have survived in other parts of Africa where the rain patterns were still adequate.

    Without the pressure we put on them and their habitats, they would have a better chance to survive a warming cycle. They have weathered such cycles before when caused by giant volcanoes or continent sized forest fires, but that may not be true today. Before humanity overran the planet, a global warming or cooling trend would have caused the ranges of animal populations to be redistributed. Some ranges would get bigger and some would get smaller. Today, nature is trapped in tiny, ever-shrinking pockets. There is no place to run, no place to hide. Global warming will be the straw that breaks the camel’s back as far as the last remaining pockets of natural ecosystems and wildlife are concerned."