Climate Change and Animal Migrations

“The ability to move, at some stage in the life
cycle, is fundamental to success in life.”

Andrew Sugden and Elizabeth Pennisi

“Animals have no choice but to move, since their
survival is at stake. ŠStudies of more than 1,000
species of plants, animals, and insects, found an
average migration rate toward the North and South
Poles of about four miles per decade in the
second half of the 20th century. That is not fast
enough. During the past 30 years the lines
marking the regions in which a given average
temperature prevails, or isotherms, have moved
poleward at a rate of about 35 miles per decade.

“As long as the total movement of isotherms
toward the poles is much smaller than the size of
the habitat, or the ranges in which the animals
live, the effect on species is limited. But now
the movement is inexorably toward the poles,
totaling more than 100 miles in recent decades.
If emissions of greenhouse gases continue to
increase at the current rate — “business as
usual” — then the rate of isotherm movement will
double during this century to at least 70 miles
per decade. If we continue on this path, a large
fraction of the species on Earth, as many as 50
percent or more, may become extinct.”
James Hansen
19 October 2006
The Planet in Peril – Part I

“Each 1 degree C of global warming will shift
temperature zones by about 160 km (100 miles). In
the northern hemisphere this means that if the
climate warms 3°C species may have to shift
northward as much as 500 km (300 miles) in order
to find suitable habitat under the new climatic

“Global warming may make a mockery of our
attempts in all nature reserves, including
Glacier National Park, to preserve natural
communities and rare, threatened, and endangered
native species.”

“Perhaps many of Glacier’s species will be able
to survive farther north, in the Banff-Jasper
area. Protection of corridors linking the Greater
Yellowstone Ecosystem, the Crown of the Continent
Ecosystem, and parks in the Canadian Rockies may
provide critical avenues for species dispersal.”

Glacier National Park Biodiversity Paper #7

In its “Managing Mountain Parks,” the UN’s Food
and Agriculture Organization says, “The major
challenges for the twenty-first century include
this one:

“To link together the isolated existing mountain
protected areas by conservation corridors along
the mountain ranges. This not only increases
effective size, but provides migration corridors
for gene flow and species movement. As the
climate changes, poleward migration corridors in
north-south ranges (e.g. the Andes) will better
accommodate temperature change, and migration
along the east-west ranges (e.g. the Western Tien
Shan) will be a response to rainfall changes.

full FAO report at:

The United Nations Environmental Programme stresses the same basic point:

“Forest management responses to climate change
should focus on maintaining species diversity on
national or continental scales through
facilitating the processes of species migration,
rather than by solely preserving specific

full UNEP report at:


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