Arctic could be Ice-Free in future Summers
Are warming conditions in the Arctic unprecedented in Earth's
history? It turns out that they are not. The Earth's climate has gone
through warming and cooling times in the past as can be seen in the
fossil record that shows tropical species in regions now too cool to
support them.
These past variations were obviously not caused by the effects of
mans activities. This does not mean that the current warming trend is
not caused, or affected by anthropogenic air pollution. There is now
increased evidence that the Arctic could face seasonally ice-free
conditions and much warmer temperatures in the future.
Scientists have documented evidence that the Arctic Ocean and Nordic
Seas were too warm to support summer sea ice during the mid-Pliocene
warm period (3.3 to 3 million years ago). This period is characterized
by warm temperatures similar to those projected for the end of this
century, and is used as an analog to understand future conditions.
The U.S. Geological Survey found that summer sea-surface temperatures
in the Arctic were between 10 to 18°C (50 to 64°F) during the
mid-Pliocene, while current temperatures are around or below 0°C (32°F).
Examining past climate conditions allows for a better understanding
of how Earths climate system really functions. USGS research on the
mid-Pliocene is the most comprehensive global reconstruction for any
warm period. This research will help refine climate models, which
currently underestimate the rate of sea ice loss in the Arctic. Loss of
sea ice could have varied and extensive consequences, such as
contributions to continued Arctic warming, accelerated coastal erosion
due to increased wave activity, impacts to large predators (polar bears
and seals) that depend on sea ice cover, intensified mid-latitude storm
tracks and increased winter precipitation in western and southern
Europe, and less rainfall in the American west.
- enn.com
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