Showing posts from February, 2016

Three kinds of warming in the Arctic

The Arctic is prone to suffer from three kinds of warming. Firstly, the Arctic is hit particularly hard by emissions, as discussed in earlier posts such as this one and this one . Secondly, warming in the Arctic is accelerating due to feedbacks, as discussed on the feedbacks page . Many such feedbacks are related to decline of the snow and ice cover in the Arctic, which is in turn made worse by emissions such as soot. Thirdly, the most dangerous feedback is release of methane from the Arctic Ocean seafloor, due to hydrates getting destabilized as heat reaches sediments. Last year, Arctic sea ice reached its maximum extent on February 25, 2015. This year, there was a lot less sea ice in the Arctic on February 25 than there was last year, as illustrated by above image. The difference is about 300,000 square km, more than the size of the United Kingdom. The image below shows that global sea ice on February 22, 2016, was only 14.22086 million square km in area. It hasn't been that low

Arctic Winter Heatwave

The Arctic is experiencing a heatwave in winter, with temperature anomalies on February 23, 2016, averaging 7.84°C or 14.11°F higher than what was common 1979-2000. The forecast for 6:00 UTC on February 23, 2016, shows an anomaly of 8.17°C or 14.71°F. Temperatures in January 2016 over the Arctic Ocean were 7.3°C (13.1°F) higher than in 1951-1980 , according to NASA data, as illustrated by the graph on the right, from an earlier post . These high temperatures go hand in hand with sea ice extent that is much lower for this time of year than since records started. As discussed in an earlier post , low sea ice extent is fueling fears that this year's maximum extent was already reached on February 9, 2016. A much higher ocean temperature is behind both the low sea ice extent and the high temperature anomalies. Ocean temperatures are particularly high where the Gulf Stream pushes water from Atlantic Ocean into the Arctic Ocean, as illustrated by the image below that compares sea surface

Has maximum sea ice extent already been reached this year?

An earlier post wondered whether maximum extent for this year had already been reached, i.e. on February 9, 2016, when sea ice extent was 14.214 million km 2 . As illustrated by the image below, extent since has been lower, including on the two most recent days on the image, i.e. on February 16 and 17, 2016, when extent was respectively 14.208 and 14.203 million km 2 . Last year (2015), maximum sea ice extent was reached on February 25. That's close to the most recent date on the image of February 17, so with El Nino still going strong, it may well be that the maximum in 2016 will be reached early. On the other hand, strong winds could spread out the sea ice and speed up its drift out of the Arctic Ocean, which may result in a larger extent, but which won't do much to strengthen the sea ice. UPDATES: On February 18, 2016 (arrow), Arctic sea ice extent was 14.186 million square km, i.e. less than it was on February 9. In fact, sea ice extent hasn't been higher on any day si

Arctic sea ice remains at a record low for time of year

For the time of year, Arctic sea ice remains at a record low since satellite records started in 1979, both for area and extent. The image below shows Arctic sea ice area up to February 12, 2016, when area was 12.49061 million square km. The image below shows Arctic sea ice extent up to February 12, 2016, when extent was 14.186 million square km. The reason for the record low sea ice is that there is more ocean heat than there used to be. The image below shows that on February 12, 2016, the Arctic Ocean sea surface temperature was as warm as 11.3°C (52.4°F) at a location near Svalbard marked by the green circle, a 10.4°C (18.7°F) anomaly. The reason for this is that the water off the east coast of North America is much warmer than it used to be. The Gulf Stream is pushing heat all the way into the Arctic Ocean. The image below shows that on February 14, 2016, sea surface temperature anomalies (compared to 1981-2011) off the east coast of North America were was as high as 10.1°C or 18.1°

Methane's Role in Arctic Warming

Arctic Ocean hit most strongly by global warming Over the past 12 months, global warming was felt most strongly over the Arctic Ocean, as above image illustrates. Over most parts of the Arctic Ocean, surface temperatures were above the top end of the scale, i.e. more than 2.5°C higher than in 1981-2010. In January 2016, air temperatures close to sea level (at 925 hPa) were more than 6°C or 13°F above average across most of the Arctic Ocean, as announced recenty . Moreover, daily average temperatures over many parts of the Arctic Ocean often exceed the top end of the scale, i.e. 20°C or 36°F higher than in 1979-2000, as illustrated by the  Climate Reanalyzer  forecast below. So, how can temperature anomalies over the Arctic Ocean at this time of year be so much higher than elsewhere on Earth? One factor is feedbacks such as changes to the jet stream and decline of snow and ice cover in the Arctic that makes that ever more sunlight is getting absorbed by the water of the Arcti