WASHINGTON (AP) — Warming air from climate change isn’t the
only thing that will speed ice melting near the poles — so will the warming
water beneath the ice, a new study points out.
Increased melting of ice in Greenland and parts of Antarctica
has been reported as a consequence of global warming, potentially raising
sea levels. But little attention has been paid to the impact of warmer water
beneath the ice.
Now, Jianjun Yin of the University of Arizona and colleagues
report the warming water could mean polar ice melting faster than had been
expected. Their report was published Sunday in the journal Nature Geoscience.
While melting floating ice won’t raise sea level, ice flowing
into the sea from glaciers often reaches the bottom, and grounded ice melted
by warm water around it can produce added water to the sea.
“Ocean warming is very important compared to atmospheric
warming because water has a much larger heat capacity than air,” Yin
explained. “If you put an ice cube in a warm room, it will melt in several
hours. But if you put an ice cube in a cup of warm water, it will disappear
in just minutes.”
In addition, Yin explained, if floating ice along the coastal
areas melts it will allow the flow of glaciers to accelerate, bringing more
ice into the seas.
“This mean that both Greenland and Antarctica are probably
going to melt faster than the scientific community previously thought,”
co-author Jonathan T. Overpeck said in a statement.
Overpeck, co-director of the University of Arizona’s
Institute of the Environment, said: “This paper adds to the evidence that we
could have sea level rise by the end of this century of around 1 meter and a
good deal more in succeeding centuries.”
The subsurface ocean along the Greenland coast could warm as
much as 3.6 degrees Fahrenheit (2 Celsius) by 2100, the researchers
reported. The warming along the coast of Antarctica would be somewhat less,
they calculated, at 0.9 degree F (0.5 C).