Escaping climate change: one if by land, two if by sea? No, according to recent results. Image: Hugh Brown, SAMS |
Results
of a study to be published this week in the journal Science show how
fast animal and plant populations would need to move to keep up with
recent climate change effects in the ocean and on land.
The answer: at similar rates.
The
study was supported by the National Science Foundation (NSF), and
performed in part through the National Center for Ecological Analysis
and Synthesis at the University of California at Santa Barbara.
“That
average rates of environmental change in the oceans and on land are
similar is not such a surprise,” says Henry Gholz, program director in
NSF’s Division of Environmental Biology.
“But
averages deceive,” Gholz says, “and this study shows that rates of
change are at times greater in the oceans than on land—and as complex as
the currents themselves.”
Greenhouse
gases have warmed the land by approximately one degree Celsius since
1960. That rate is roughly three times faster than the rate of ocean
warming. These temperatures have forced wild populations to adapt—or to
be on the move, continually relocating.
Although
the oceans have experienced less warming overall, plants and animals
need to move as quickly in the sea as they do on land to keep up with
their preferred environments.
Surprisingly,
similar movement rates are needed to out-run climate change. On land,
movement of 2.7 km (1.6 miles) per year is needed and in the
oceans, movement of 2.2 km (1.3 miles) per year is needed.
“Not
a lot of marine critters have been able to keep up with that,” says
paper co-author John Bruno, a marine ecologist at the University of
North Carolina at Chapel Hill. “Being stuck in a warming environment can
cause reductions in the growth, reproduction and survival of
ecologically and economically important ocean life such as fish, corals
and sea birds.”
“These
results provide valuable insights into how climate will affect
biological communities worldwide,” says David Garrison, director of
NSF’s Biological Oceanography Program.
The
analysis is an example of the value of synthesis research centers,
Garrison says, in addressing society’s environmental challenges.
“With
climate change we often assume that populations simply need to move
poleward to escape warming, but our study shows that in the ocean, the
escape routes are more complex,” says ecologist Lauren Buckley of the
University of North Carolina at Chapel Hill, also a co-author of the
paper.
“For
example, due to increased upwelling, marine life off the California
coast would have to move south [rather than north] to remain in its
preferred environment.”
“Some
of the areas where organisms would need to relocate the fastest are
important biodiversity hot spots, such as the coral triangle region in
southeastern Asia,” says lead author Mike Burrows of the Scottish
Association of Marine Science.
Whether by land or by sea, according to these results, all will need to be on the fly.
