Projected status of the Mediterranean Climate Envelope in 2070-2099 relative to 1960-1989 under the A2 emissions scenario (Aschmann definition)

This data layer shows the projected status of the mediterranean climate extent (MCE) at the end of the 21st century under the A2 emissions scenario. The MCE definition is derived from the criteria published by H. Aschmann in 1973. The methodology to determine the current MCE and the projected climate changes are described in an open access online peer reviewed article in PlosOne (http://www.plosone.org/article/info:doi/10.1371/journal.pone.0006392) by Klausmeyer and Shaw (2009). The abstract from this publication is as follows:

"Mediterranean climate is found on five continents and supports five global biodiversity hotspots. Based on combined downscaled results from 23 atmosphere-ocean general circulation models (AOGCMs) for three emissions scenarios, we determined the projected spatial shifts in the mediterranean climate extent (MCE) over the next century. Although most AOGCMs project a moderate expansion in the global MCE, regional impacts are large and uneven. The median AOGCM simulation output for the three emissions scenarios project the MCE at the end of the 21st century in Chile will range from 129-153% of its current size, while in Australia, it will contract to only 77-49% of its current size losing an area equivalent to over twice the size of Portugal. Only 4% of the land area within the current MCE worldwide is in protected status (compared to a global average of 12% for all biome types), and, depending on the emissions scenario, only 50-60% of these protected areas are likely to be in the future MCE. To exacerbate the climate impact, nearly one third (29-31%) of the land where the MCE is projected to remain stable has already been converted to human use, limiting the size of the potential climate refuges and diminishing the adaptation potential of native biota. High conversion and low protection in projected stable areas make Australia the highest priority region for investment in climate-adaptation strategies to reduce the threat of climate change to the rich biodiversity of the mediterranean biome."


References:
Aschmann H (1973) Distribution and Peculiarity of Mediterranean Ecosystems. In: Di Castri F, Mooney HA, editors. Mediterranean type ecosystems; origin and structure. Berlin, New York: Springer-Verlag. pp. xii, 405 p. illus. 425 cm.

Klausmeyer, K. R. and M. R. Shaw (2009). Climate Change, Habitat Loss, Protected Areas and the Climate Adaptation Potential of Species in Mediterranean Ecosystems Worldwide. PLoS ONE 4(7): e6392. http://www.plosone.org/article/info:doi/10.1371/journal.pone.0006392