Arctic News: RF

Showing posts with label RF. Show all posts

Saturday, December 8, 2018

Carbon dioxide emissions are rising

CO₂ emissions are rising

In models used by the Intergovernmental Panel on Climate Change (IPCC), carbon dioxide (CO₂) emissions were expected to come down in line with pledges made at the Paris Agreement. Yet, the Global Carbon Project projects growth in CO₂ emissions from fossil fuels and industry in 2018 to be +2.7%, within uncertainty margins from +1.8% to +3.7%.

This rise is in line with an image from an earlier post that shows growth of CO₂ in the atmosphere to be accelerating.

[ Growth of CO₂ in ppm, based on annual Mauna Loa data (1959-2017), with 4th-order polynomial trend added ]

Methane emissions rising as well

And it's not just CO₂ emissions that are rising. Methane emissions are rising as well. Sadly, politicians typically ignore this elephant in the room, in particular seafloor methane emissions that threaten to trigger a huge temperature rise within years.

[ ignoring the elephant in the room, i.e. seafloor methane ]

The MetOp image below shows high methane levels over oceans on December 9, 2018, pm, at 469 mb. Levels over the Arctic Ocean in particular are very high, as the large areas solidly colored magenta indicate.

The MetOp image shows many areas where no data were available, as indicated by the color grey. The NPP images don't have as many grey areas. The image below confirms very high methane levels over the Arctic Ocean on December 9, 2018 pm, closer to the surface, i.e. at 840 mb. While there still are many grey areas, the absence of data for many of them is due to altitude, since large parts of Greenland, Antarctica and the Himalayas are rather high.

As discussed in earlier posts, large amounts of methane appear to be rising from the Arctic Ocean. As the methane rises higher in the atmosphere, it moves closer to the Equator. The NPP image below shows levels at 399 mb on December 9, 2018, pm. At this altitude, there are very few grey areas, so it's possible to get a fuller picture of where the highest levels of methane are. Ominously, levels as high as 3060 ppb were reached.

El Niño events will intensify

The image on the right shows that, on December 30, 2018, sea surface temperature anomalies were as high as 9.7°C or 17.4°F in the Pacific Ocean, 11.1°C or 20°F in the Atlantic Ocean and 17.1°C or 30.8°F near Svalbard in the Arctic Ocean.

NOAA expects El Niño to form and continue through the Northern Hemisphere winter 2018-19 (~90% chance). A recent study concludes that global warming will enhance both the amplitude and the frequency of eastern Pacific El Niño events.

Albedo change

Albedo change due to decline of the snow and ice cover is another feedback that the IPCC has yet to come to grips with. The IPCC seems to have hoped that albedo loss in the Arctic was somehow compensated for by albedo gain in the Antarctic.

The IPCC (in AR5, WG1) did find a significant increase in Antarctic annual mean sea ice extent that is very likely in the range of 1.2 to 1.8 % per decade between 1979 and 2012 (0.13 to 0.20 million km² per decade) (very high confidence).

As the image below shows, global sea ice extent steadily came down, but then grew somewhat until end 2014. From end 2014 on, Antarctic sea ice extent fell rapidly, with huge repercussions for global sea ice extent, as also illustrated by the image on the right that highlights the most recent years of the graph below.

At the end of 2016, Antarctic sea ice extent was a lot smaller than it was at the end of 2014. Such a difference in sea ice extent corresponds with a huge difference in radiative forcing (RF).

Antarctic sea ice extent was 4.913 million km² on January 5, 2019, a record low for the time of year and 4.212 million km² less than it was on January 5, 2015, when extent was 9.125 million km².

This decline could make a difference of 1.3 W/m² in RF. By comparison, the IPCC estimated the net RF from all emissions by people from 1750 to 2011 at 1.6 W/m².

As the image below shows, global sea ice extent was at a record low for the time of year on Dec. 28, 2018, and looks set to go lower in 2019.

Antarctic sea ice decline is only part of the picture, there's also Arctic sea ice decline and there's decline of the snow and ice cover on land.

Joint impact