Arctic sea ice volume stops growing in mid-October

Is this just a temporary phenomenon. If it is not it is unprecedeted and very worrying.

We have NOT dodged a bullet, it seems

Arctic sea ice volume has declined in mid-October

Arctic sea ice volume is down from 4th to 3rd lowest.

For the geeks, these are the best figures we get for daily ice.
Daily volume: 5,544 km³ (3rd lowest for the date) Δ –33/day
–14/week, +887/month, +127/year, +787/5year (+17%)
Daily extent: 6,354,723 km² (5th lowest for the date) Δ +79k/day
+632k/week, +1813k/month, +694k/year, +964k/5year (+18%)

2017 volume maximum 20,756 km³ on April 18th (*lowest*)
2017 volume minimum 4,539 km³ on September 11th (4th lowest)
2017 extent maximum 13,878,287 km² on March 6th (*lowest*)
2017 extent minimum 4,472,225 km² on September 9th (6th lowest)

However, the above daily numbers carry a taste of ?. If you don’t want to cherry–pick your data to make a point, you may want to look at the latest, updated, running annual average. The ice, after all, has to be out there and survive those waves 24/7, 365 days of the year.

Annual volume: 12,598 km³ (*record* low) Δ +0.5/day
+7.6/week, +22/month, –1,505/year, –1,099/5year (–8%)
Annual extent: 9,829,583 km² (*record* low) Δ +1.9k/day
+13k/week, +21k/month, –77k/year, –180k/5year (–1.8%)

Source: JAXA / PIOMAS (app estimate) for October 15th 2017

*If* this plunge is real, it is truly amazing & devastating, namely because it seems to be initiated on October 12th, the exact same date as the verified and confirmed October 2016 plunge. This is surprising because, if 2016 volume trends hard downward those same days, it gets even harder for 2017 ice to register as a plunge on top of that (in part because annual average volume heads down only if yesterday's date this year is lower than same date last year). Of course, we won't know before first week of November when Washington.EDU releases its numbers.

https://forum.arctic-sea-

ice.net/index.php/topic,2141.msg131565.html#msg131565


This video gives a rare impression of just how thin the ice is - at 80 deg. N




Meanwhile methane levels have reached a record

This is a discussion between Sandy Schoelles and Jennifer Hynes.

Menwhile CO2 levels are going up and up

Atmospheric CO2 keeps climbing

http://folk.uio.no/roberan/t/MLO_weekly.shtml

Download image: PNG | animated movie

Discussion

The atmospheric concentration of CO2 has been steadily climbing since mankind began its long-term climate experiment of liberating long-buried fossil carbon. Before we began, concentration was below 300 ppm, but since then we have sent more than 2 trillion tonnes of CO2 into the atmosphere. While some of that has beenabsorbed by land and ocean 'sinks', much of it remains in the atmosphere, and will stay there for many hundreds of years.

In an article published in June 2016, Richard Betts and colleagues at the UK's Met Office Hadley Centre forecast that the monthly average concentration of CO2 at Mauna Loa would remain above 400ppm all year "and hence for our lifetimes". The figure above bears out the first part of that statement, and moreover shows that also weekly averages stayed above 400ppm throughout 2016. In February 2017 they made a new forecast for 2017, and the following figure indicates how well that forecast is performing against measurements (click to enlarge). (Note that the following figure presents weekly concentrations from NOAA but monthly concentrations from Scripps, and as these datasets are entirely independent they do not always line up.)

The seasonal cycle is dominated by northern hemisphere forests, following the pattern of plants' photosynthesis, which stores CO2, and microbial decay, which releases it again (more info). The figure to the right shows the global average concentration since 1959 (click to enlarge).

Here's another version of the Mauna Loa plot, with apologies to Hokusai (click to enlarge).

Data Sources

NOAA releases weekly average concentrations of CO2 measured at Mauna Loa, Hawaii here.

The forecast by the Met Office Hadley Centre is based on independent measurements of CO2 concentration at Mauna Loa made by the Scripps Institution of Oceanography, available here.

This figure was inspired by similar ones produced by Climate Central here and here.

NASA pinpoints cause of Earth's recent record carbon dioxide spike

The last El Nino in 2015-16 impacted the amount of carbon dioxide that Earth's tropical regions released into the atmosphere, leading to Earth's recent record spike in atmospheric carbon dioxide. The effects of the El Nino were different in each region. Credit: NASA-JPL/Caltech.
› Larger view

https://climate.nasa.gov/news/2639/nasa-pinpoints-cause-of-earths-recent-record-carbon-dioxide-spike/

A new NASA study provides space-based evidence that Earth's tropical regions were the cause of the largest annual increases in atmospheric carbon dioxide concentration seen in at least 2,000 years.

Scientists suspected the 2015-16 El Nino — one of the largest on record — was responsible, but exactly how has been a subject of ongoing research. Analyzing the first 28 months of data from NASA's Orbiting Carbon Observatory-2 (OCO-2) satellite, researchers conclude impacts of El Nino-related heat and drought occurring in tropical regions of South America, Africa and Indonesia were responsible for the record spike in global carbon dioxide. The findings are published in the journal Science Friday as part of a collection of five research papers based on OCO-2 data.

"These three tropical regions released 2.5 gigatons more carbon into the atmosphere than they did in 2011," said Junjie Liu of NASA's Jet Propulsion Laboratory in Pasadena, California, who is lead author of the study. "Our analysis shows this extra carbon dioxide explains the difference in atmospheric carbon dioxide growth rates between 2011 and the peak years of 2015-16. OCO-2 data allowed us to quantify how the net exchange of carbon between land and atmosphere in individual regions is affected during El Nino years." A gigaton is a billion tons.

In 2015 and 2016, OCO-2 recorded atmospheric carbon dioxide increases that were 50 percent larger than the average increase seen in recent years preceding these observations. These measurements are consistent with those made by the National Oceanic and Atmospheric Administration (NOAA). That increase was about 3 parts per million of carbon dioxide per year — or 6.3 gigatons of carbon. In recent years, the average annual increase has been closer to 2 parts per million of carbon dioxide per year — or 4 gigatons of carbon. These record increases occurred even though emissions from human activities in 2015-16 are estimated to have remained roughly the same as they were prior to the El Nino, which is a cyclical warming pattern of ocean circulation in the central and eastern tropical Pacific Ocean that can affect weather worldwide.

Using OCO-2 data, Liu's team analyzed how Earth's land areas contributed to the record atmospheric carbon dioxide concentration increases. They found the total amount of carbon released to the atmosphere from all land areas increased by 3 gigatons in 2015, due to the El Nino. About 80 percent of that amount — or 2.5 gigatons of carbon — came from natural processes occurring in tropical forests in South America, Africa and Indonesia, with each region contributing roughly the same amount.

The team compared the 2015 findings to those from a reference year — 2011 — using carbon dioxide data from the Japan Aerospace Exploration Agency's Greenhouse Gases Observing Satellite (GOSAT). In 2011, weather in the three tropical regions was normal and the amount of carbon absorbed and released by them was in balance.

"Understanding how the carbon cycle in these regions responded to El Nino will enable scientists to improve carbon cycle models, which should lead to improved predictions of how our planet may respond to similar conditions in the future," said OCO-2 Deputy Project Scientist Annmarie Eldering of JPL. "The team's findings imply that if future climate brings more or longer droughts, as the last El Nino did, more carbon dioxide may remain in the atmosphere, leading to a tendency to further warm Earth."

While the three tropical regions each released roughly the same amount of carbon dioxide into the atmosphere, the team found that temperature and rainfall changes influenced by the El Nino were different in each region, and the natural carbon cycle responded differently. Liu combined OCO-2 data with other satellite data to understand details of the natural processes causing each tropical region's response.

In eastern and southeastern tropical South America, including the Amazon rainforest, severe drought spurred by El Nino made 2015 the driest year in the past 30 years. Temperatures also were higher than normal. These drier and hotter conditions stressed vegetation and reduced photosynthesis, meaning trees and plants absorbed less carbon from the atmosphere. The effect was to increase the net amount of carbon released into the atmosphere.

In contrast, rainfall in tropical Africa was at normal levels, based on precipitation analysis that combined satellite measurements and rain gauge data, but ecosystems endured hotter-than-normal temperatures. Dead trees and plants decomposed more, resulting in more carbon being released into the atmosphere. Meanwhile, tropical Asia had the second-driest year in the past 30 years. Its increased carbon release, primarily from Indonesia, was mainly due to increased peat and forest fires — also measured by satellite instruments.

"We knew El Ninos were one factor in these variations, but until now we didn't understand, at the scale of these regions, what the most important processes were," said Eldering. "OCO-2's geographic coverage and data density are allowing us to study each region separately."

Scott Denning, professor of atmospheric science at Colorado State University in Fort Collins and an OCO-2 science team member who was not part of this study, noted that while scientists have known for decades that El Nino influences the productivity of tropical forests and, therefore, the forests' net contributions to atmospheric carbon dioxide, researchers have had very few direct observations of the effects.

"OCO-2 has given us two revolutionary new ways to understand the effects of drought and heat on tropical forests: directly measuring carbon dioxide over these regions thousands of times a day; and sensing the rate of photosynthesis by detecting fluorescence from chlorophyll in the trees themselves," said Denning. "We can use these data to test our understanding of whether the response of tropical forests is likely to make climate change worse or not."

The concentration of carbon dioxide in Earth's atmosphere is constantly changing. It changes from season to season as plants grow and die, with higher concentrations in the winter and lower amounts in the summer. Annually averaged atmospheric carbon dioxide concentrations have generally increased year over year since the early 1800s — the start of the widespread Industrial Revolution. Before then, Earth's atmosphere naturally contained about 595 gigatons of carbon in the form of carbon dioxide. Currently, that number is 850 gigatons.

The annual increase in atmospheric carbon dioxide levels and the magnitude of the seasonal cycle are determined by a delicate balance between Earth's atmosphere, ocean and land. Each year, the ocean, plants and trees take up and release carbon dioxide. The amount of carbon released into the atmosphere as a result of human activities also changes each year. On average, Earth's land and ocean remove about half the carbon dioxide released from human emissions, with the other half leading to increasing atmospheric concentrations. While natural processes are responsible for the exchange of carbon dioxide between the atmosphere, ocean and land, each year is different. In some years, natural processes remove as little as 20 percent of human emissions, while in other years they scrub as much as 80 percent.

OCO-2, launched in 2014, gathers global measurements of atmospheric carbon dioxide with the resolution, precision and coverage needed to understand how this important greenhouse gas — the principal human-produced driver of climate change — moves through the Earth system at regional scales, and how it changes over time. From its vantage point in space, OCO-2 is able to make roughly 100,000 measurements of atmospheric carbon dioxide each day, around the world.

Institutions involved in the Liu study include JPL; the National Center for Atmospheric Research in Boulder, Colorado; the University of Toronto; Colorado State University; Caltech in Pasadena, California; and Arizona State University in Tempe.

For more information on NASA's Orbiting Carbon Observatory-2 mission, visit:

https://www.nasa.gov/oco2