Temperature Rise

How much could temperatures rise by 2026? The above image shows how a rise of 10°C (18°F) could occur by the year 2026, based on temperature anomalies from 1750 for February and on progressive growth of warming elements. The image below shows the same rise in another way.

Such a rise could take place even more rapidly, as discussed in the earlier post 10°C or 18°F warmer by 2021? For more on calculating the temperature rise from 1750 to 2016, see this page and this post.

Crucial will be the decline of snow & sea ice and associated feedbacks. Ominously, global sea ice is at a record low at the moment, as illustrated by the graph below by Wipneus.

[ click on images to enlarge ]

Arctic sea ice extent on August 15, 2017, was the 2nd lowest on record for the time of year (behind only 2012), as illustrated by the image on the right.

While extent was lower on August 15, 2012, Arctic sea ice is very thin at the moment, as the Arctic Ocean has become warmer, and sea ice could disappear altogether in one month time, as discussed in earlier posts such as this one.

And ominously, July 2017 was the hottest July on record, as illustrated by the image below.

[ click on images to enlarge ]

The July temperature anomaly was particularly high on land on the Southern Hemisphere (1.53°C or 2.75°F, compared to 1901-2000), as illustrated by the image on the right, showing a linear trend over the period 2012-2017.

Above image shows that July 2017 was 2.25°C (4.05°F) warmer than the annual global mean 1980-2015 (seasonal cycle). Only in August 2016 was it warmer (2.29°C), but then again, August 2017 looks set to be warmer than that yet.

The fall in thickness of the sea ice indicates that the buffer has gone that until now has consumed heat entering the Arctic Ocean during the melting season. In the absence of this buffer, where can all this extra heat go? Sea ice will start sealing off much of the surface of the Arctic Ocean by the end of September 2017, making it hard for more heat to escape from the Arctic Ocean by entering the atmosphere.

The Buffer has gone, feedback #14 on the Feedbacks page

The danger is that much of the extra heat will instead reach sediments at the seafloor of the Arctic Ocean that contain huge amounts of methane in currently still frozen hydrates.

[ click on images to enlarge ]

Higher temperatures could destabilize methane hydrates, resulting in huge methane eruptions.

A polynomial trend, based on NOAA July 1983 to January 2017 global monthly mean methane data, points at twice as much methane by 2034, as the image on the right shows. Stronger methane releases from the seafloor could make such a doubling occur even earlier. Over the next decade, methane will cause more warming than CO₂ ─ twice as much methane will cause more than twice as much warming.

Methane reached peaks as high as 2881 ppb at 479 mb on August 18, 2017, as the combination image below shows (left panel, top left corner).

[ click on images to enlarge ]

The image doesn't specify the origin of the peak, but when levels are that much above the mean, the likely cause is either wildfires or clathrate destabilization. As the image in the right panel shows, methane levels at 280 mb were also very high over the Arctic Ocean north of Canada in the morning that day, which is unusual at such an altitude.

The image below shows that mean global methane reached a level of 1881 ppb at 280 mb (MetOp-1, am) on August 15, 2017.

Breaking News

Temperature Rise

Bài đăng phổ biến

Breaking News

Temperature Rise

Social Counter

Bài đăng phổ biến