Melt­ing ice in the Arc­tic still a ma­jor prob­lem

Bray People - - LIFESTYLE - JIM HUR­LEY

THE EURO­PEAN En­vi­ron­ment Agency (EEA) has pub­lished a report de­scrib­ing the sum­mer of 2012 in the Arc­tic. On the face of it the publi­ca­tion of that report would seem to have lit­tle or noth­ing to do with us here in Ire­land but it does im­pact on us in that chang­ing cli­mate in the Arc­tic is one of sev­eral fac­tors caus­ing sea level to rise here.

The prob­lem in the Arc­tic is four­fold. First, due to global warm­ing ice is melt­ing at a faster rate than many ex­perts had pre­dicted. Year on year the limit of sum­mer sea ice has got less and less since records be­gan in 1979. The ex­tent of the sea ice fell from a Septem­ber av­er­age of 6.5 mil­lion kilo­me­tres squared over the last three decades to a record low of less than 4 mil­lion kilo­me­tres squared in Septem­ber 2012. Fur­ther­more, the re­main­ing ice is thin­ner and is there­fore more likely to melt faster.

The sec­ond prob­lem is that sum­mer snowfall is de­clin­ing. In the past the great ex­panse of white­ness from snow and ice in the Arc­tic acted as a re­flec­tor bounc­ing the heat of the Sun back into space. Nowa­days the in­creas­ing ex­tent of darker ar­eas acts as a heat ab­sorber soaking in the Sun's en­ergy thereby warm­ing the planet re­sult­ing in more ice melt­ing that in turn causes sea level to rise.

The third prob­lem is that per­mafrost is melt­ing at an ac­cel­er­ated rate. Per­mafrost is frozen soil. In the past the per­mafrost acted as a sink for car­bon diox­ide and meth­ane gases. Nowa­days the per­mafrost is re­leas­ing th­ese gases as it thaws. In­creased green­house gasses in the at­mos­phere traps heat thereby warm­ing the planet, re­sult­ing in more ice melt­ing and so on.

And the fourth and fi­nal prob­lem is that the huge Green­landic ice sheet is los­ing ice mass at an alarming rate. It has been es­ti­mated that if the Green­land ice sheet was to melt in its en­tirety global sea level would rise by as much as a fright­en­ing seven me­tres.

At present sea level is ris­ing at the rate of about 3mm per year with very high lev­els of un­cer­tainty about how that might ac­cel­er­ate. What is likely to hap­pen in the Arc­tic be­fore the end of this cen­tury and how it will im­pact on the four mil­lion peo­ple who live there is largely un­known. How wildlife will cope and how cli­mate will be af­fected is also largely un­known.

Chang­ing cli­mate in the Arc­tic is one of sev­eral fac­tors caus­ing sea level to rise here.

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