Climate Change in the Arctic - The Changing Arctic Environment: The Arctic Messenger - page 313

Summer Arctic sea ice is melting much faster and earlier than expected. We now
expect to see an ice-free Arctic ocean in summer somewhere between 2030 and
2050.

· Increased levels of CO 2 in the atmosphere and its subsequent uptake by the ocean

is leading to a lowering of ocean pH (ocean acidification). The Arctic Ocean is
particularly sensitive to the chemistry that leads to acidification. In some parts of
the Arctic, levels of acidification have already been recorded that have the poten-
tial to cause significant ecosystem impacts.

· There are signs that a warming Arctic that lacks the insulation of summer ice

between sea and air may be beginning to significantly influence mid-latitude
weather.

· Arctic marine, terrestrial and freshwater ecosystems are all beginning to show

signs of being impacted by Arctic warming.

· For better or for worse, Arctic indigenous and nonindigenous peoples face an un-

certain future.

· We and our political leaders are running out of time to effectively control or allevi-

ate the progression of these events.

With these facts in mind, what about that question posed near the beginning of the ecosys-
tem impact section? Are we watching the initial collapse of an Arctic ecosystem (physical
and biological) that has existed for at least the past several thousand years? All the eviden-
ce indicates we have embarked on a course towards this outcome. We have learned in this
chapter of the moderating role that the Arctic plays in our global climate system. Could the
Arctic Messenger therefore be telling us something foreboding about the possible future of
ecosystems elsewhere once this moderating role has weakened?

1 IPCC, 2013. “Summary for Policymakers.” In Stocker et al. (eds.), Climate Change 2013: The Physical
Science Basis , p.4. Cambridge, UK, and New York: Cambridge University Press.