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Rapidly growing 'Seal' over Arctic Ocean Arctic sea ice extent and especially concentration are now growing rapidly, as illustrated by the Naval Research Lab animation on the right. This means that the sea ice is effectively sealing off the water of the Arctic Ocean from the atmosphere, reducing the chances of transfer of ocean heat from the water to the atmosphere. Conversely, the risk grows that ocean heat will reach the seafloor. Furthermore, this seal makes that less moisture evaporates from the water, which together with the change of seasons results in lower hydroxyl levels at the higher latitudes of the Northern Hemisphere, in turn resulting in less methane being broken down in the atmosphere over the Arctic. Rising Ocean Heat Water temperatures are very high in the Arctic. Above image shows Arctic sea surface temperature anomalies as at September 24, 2015. The risk of ocean heat reaching the Arctic Ocean seafloor has increased significantly over the years, due to rising...

It looks like sea ice has passed its minimum extent for the year 2015, as illustrated by the image below. There are some differences between the various websites measuring extent, such as to whether the 2015 low was the third or fourth lowest. Japanese measurements show that sea ice extent was 4.26 million square km on September 14, 2015, i.e. lower than the 2011 minimum of 4.27 million square km, as illustrated by the image below. Meanwhile, the Polar Science Center at the University of Washington has announced that Arctic sea ice volume minimum was reached on September 12, 2015, with a total volume of 5,670 cubic km. The image below shows a polynomial trendline based on their annual Arctic sea ice volume minima, including this volume for 2015. Importantly, the sea ice in many places is now less thick than it was in 2012, as illustrated by the image below, showing sea ice thickness on September 27, 2012 (panel left) and a forecast for September 27, 2015 (panel right). The reason for...

Across the oceans, the August 2015 globally-averaged sea surface temperature was 0.78°C (1.40°F) above the 20th century average—the highest temperature for any month in the 1880–2015 record. NOAA analysis further shows that in August 2015, the sea surface on the Northern Hemisphere was 1.02°C (1.84°F) warmer than it was in the 20th century, as illustrated by the graph below. As the image below shows, the August data for sea surface temperature anomalies on the Northern Hemisphere contain a trendline pointing at a rise of 2°C (3.6°F) well before the year 2030. In other words, if this trend continues, the Northern Hemisphere sea surface will be 2°C (3.6°F) warmer in about a dozen years time from now. Such a temperature rise would be catastrophic, as there are huge amounts of methane contained in the form of hydrates and free gas in sediments under the Arctic Ocean seafloor. A relatively small temperature rise of part of these sediments could cause a huge abrupt methane eruption, further...

The image below shows that Arctic sea ice had reached a level of 4.45 million square kilometers on September 16, 2015 (end of dark blue line at center of image). NSIDC has meanwhile called the 2015 minimum , but the first sentence of their post hastens to add that on September 11, Arctic sea ice reached its  likely  minimum for 2015,  at 4.41 million square kilometers (1.70 million square miles), putting 2015 in the fourth lowest place since satellite records began. Arctic sea ice minimum was lower only in 2012 (dotted line), 2007 (light blue line) and 2011 (orange line). Sea ice extent was 4.413 million square kilometers both on September 9, 2015, as well as on September 10 and 11, 2015. September 9 would be early for the sea ice to reach its minimum, as a comparison with earlier years on above image illustrates. The dark blue line on above image shows that sea ice extent fell slightly on September 16, compared to the day before, and is now below the 2011 ...

Will it be 3.27°C warmer by the year 2030? In December 2015, world delegates will descend on Paris to ensure that global warming will not cross the guardrail of 2°C above pre-industrial levels . [ click on images to enlarge them ] In a way, we have already crossed this guardrail. NOAA data show that the year-to-date land surface temperature was 1.47°C above the 20 th century average on the Northern Hemisphere in 2015, as illustrated by the image on the right. Granted, there was less warming on the Southern Hemisphere, so the globally-averaged land surface temperature was a little bit lower, i.e. 1.34°C above the 20 th century average. For reference, the image below on the right gives an overview of mean 1901-2000 temperatures. Anyway, the difference between hemispheres is small and not very relevant since most people live on the Northern Hemisphere. [ click on image to enlarge ] More importantly, this 1.47°C rise is a rise compared to the 20 th century average. The 20 th centu...

The image below, from Arctic-roos.org , shows Arctic sea ice extent up to September 6, 2015. Editorial note: The dramatic drop in sea ice extent shown on the image below turns out to be an error. The website at Arctic-roos.org is being updated and will show the correct extent soon. The image shows a recent drop in sea ice extent that is so dramatic (red line, i.e. extent for the year 2015) that some think that it must be a glitch in the system. Even so, it should act as a warning about deterioration of the sea ice in the Arctic. As discussed in earlier posts, the sea ice today is in a terrible condition. Thick sea ice is virtually absent compared to the situation in the year 2012 around this time of year, as illustrated by the image below that compares sea ice thickness on September 5, 2012 (left panel) with September 5, 2015 (right panel). Furthermore, sea surface temperatures are very high. The North Pacific, on September 3, 2015, was more than 1°C (1.8°F) warmer than it was compare...

Presentation by Jennifer Hynes on runaway feedbacks in the Arctic and the resulting threat of near-term human extinction. At  youtube.com/watch?t=309&v=L19JBY0kNmo There are links to the transcript and to the complete set of slides of the presentation at Jennifer Hynes' blog . In case you are looking for the earlier presentation by Jennifer Hynes, called 'The Arctic Methane Monster's Rapid Rise', it's at youtube.com/watch?v=a9PshoYtoxo and is also displayed below. Methane Monster II ~ Demise of the Arctic by Jennifer Hynes http://arctic-news.blogspot.com/2015/09/methane-monster-2-demise-of-the-arctic.html Posted by Sam Carana on  Saturday, September 5, 2015

by David Spratt Spanish version There is an El Niño in full swing which helps push average global temperatures higher, and records are being broken, but just how hot is it? For several years, we have heard that global warming has pushed temperatures higher by around 0.8 to 0.85 degrees Celsius (°C). But in 2015, that number is not even close. Even before this year's strong El Niño developed, 2015 was a hot year. The first few months of the year broken records for the hottest corresponding period in previous years all the way back to the start of the instrumental record in 1880. Each month, new records fell. With the July data in, NOAA, the US Government's National Oceanic and Atmospheric Administration,  reported that July was the hottest month among the 1627 months on record since 1880, and the first seven months of the year was the hottest January-July on record: The July average temperature across global land and ocean surfaces was 0.81°C above the 20th century average. As ...