Arctic News: 10 degrees

Showing posts with label 10 degrees. Show all posts

Tuesday, February 20, 2018

IPCC seeks to downplay global warming

The graph below shows global warming for a 30-year period centered on January 2018, using NASA 2003 to January 2018 LOTI anomalies from 1951-1980, adjusted by 0.59°C to cater for the rise from preindustrial to 1951-1980, and with a polynomial trend added.

From: ECMWF Nino Plumes

Above graph shows that the 1.5°C guardrail, set at the Paris Agreement, was crossed in 2016 and that a 10°C (18°F) warming could eventuate within a decade or so.

The variations in above temperature data are strongly influenced by El Niño/La Niña. We currently are in a La Niña period, during which surface temperatures are suppressed, whereas surface temperatures in 2016 were much above the trendline, due to El Niño.

The ECMWF forecast from 1 February 2018 on the right indicates that we're heading for another El Niño, i.e. surface temperatures will be rising strongly over the coming months.

The IPCC seeks to downplay the amount of global warming that has already occurred and that looks set to eventuate over the next decade or so. A leaked draft of the IPCC 'Special Report on 1.5°C above pre-industrial' (First Order Draft of SR1.5 SPM) estimates that the global mean temperature reached approximately 1°C above pre-industrial levels around 2017/2018. The IPCC appears to have arrived at this estimate using an extrapolation or near term predictions of future warming so that the level of anthropogenic warming is reported for a 30 year period centered on today.

This 1°C IPCC estimate looks quite incredible when calculating the temperature rise using NASA's data for the two most recent years for which data are available (2016/2017), which shows a warming of 0.95°C when using a baseline of 1951-1980 and a warming of 1.23°C when using a baseline of 1890-1910.

Indeed, the temperature rise differs depending on which baseline is used, and when using preindustrial as a baseline, i.e. the baseline agreed to at the Paris Agreement, indications are that temperatures have already risen by more than 1.5°C, as also discussed in an earlier post.

Furthermore, when using a 30-year period centered on January 2018, the current temperature will have to be calculated over the past 15 years and estimated for the next 15 years, i.e. up to the year 2033.

To arrive at a 1°C rise for the 30-year period, the IPCC must somehow assume that temperatures will magically fall dramatically over the next 15 years, whereas indications are that temperatures will instead rise dramatically over the next decade or so.

The image on the right shows that 10°C (18°F) warming from preindustrial could eventuate within one decade when taking into full account the warming that could result from the elements depicted in the stacked bar. Each of these warming elements is discussed in more detail at the extinction page.

The image below shows the rise from 1750 to 2030, in surface temperatures (land+ocean), rather than in anomalies.

The situation is dire and calls for comprehensive and effective action, as described in the Climate Plan.

Links

• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html

• Extinction
https://arctic-news.blogspot.com/p/extinction.html

• How much warming have humans caused?
https://arctic-news.blogspot.com/2016/05/how-much-warming-have-humans-caused.html

Wednesday, August 16, 2017

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.