Environmental Engineering Reference
In-Depth Information
Chapter 3
Adaptation
Kirk R. Klausmeyer and M. Rebecca Shaw
INTRODUCTION
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 pro-
jected 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 to 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.
The mediterranean biome is a global conservation priority [1, 2] owing to high
plant species diversity and density that rivals that of tropical rainforests [3, 4]. The
biome's mild climate and proximity to the ocean also makes it attractive to humans, re-
sulting in disproportionately high conversion for agriculture, development, and other
human uses [5, 6]. Found on fi ve continents, the mediterranean biome includes the
Mediterranean Basin, the western US (California) and Mexico (northwest Baja), cen-
tral Chile, the cape region of South Africa, and south and southwestern Australia [4].
These fi ve areas cover just 2% of the Earth's land area, but support 20% of the Earth's
known vascular plant diversity [3, 7]. Despite this biome's relative biological wealth,
formal land management for biodiversity conservation is lagging, as it has the second
lowest level of land protection of all the 13 terrestrial biomes [5]. By 2,100, the medi-
terranean biome is projected to experience the largest proportional loss of biodiversity
of all terrestrial biomes due to its signifi cant sensitivity to multiple biodiversity threats
and interactions among these threats [8].
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