In a glaring exposure, scientists have said that the sea-ice extent in the Arctic appears to have arrived at its yearly minimum this month. This low was reached on 13 September.
This summer’s marine floes were reduced in cover to 5.10 million sq km (1.97 million sq mi), says the US National Snow and Ice Data Center report.
It represents almost 50% more ice than the spectacular satellite-era record-minimum achieved this time last year – when floes were reduced to just 3.41 million sq km (1.32 million sq mi).
This year represents the sixth smallest cover recorded by the satellites. It is close in size to that seen in September 2009. However, the NSIDC characterizes the development as a “temporary reprieve”.
Steadily warming conditions in the far north have seen the annual mean ice extent since 1979 – the beginning of continuous space-based observations – fall by about 4% per decade.
“This year, we’ve had pretty cold conditions in the Arctic compared to the last few summers,” Dr Julienne Stroeve, a NSIDC research scientist said.
“So, for example, instead of having a high pressure centred over the central Arctic and the Beaufort Sea that tended to bring in warm air, we had a bunch of low-pressure systems. And that just kept things quite cool. But I think it’s interesting that even though it was cold, we got an extent of 5.10 million sq km, which is still quite a bit below the long-term mean.”
In the Antarctic, winter sea ice reached its maximum extent on September 18, NSIDC data shows. Antarctic winter extent has been growing by about 1-2% per decade.