Red alert for northern Siberia as heat shocks threaten life on tundra

https://thebarentsobserver.com/en/arctic-ecology/2020/05/red-alert-northern-siberia-heat-shocks-threaten-life-tundra

Arctic parts of Siberia in the period January-April 2020 had the world’s biggest deviation from average temperatures. Map by NOAA

New temperature maps for the endless stretches of Russian Arctic lands bear witness of unprecedented warming.
May 25, 2020

April 2020 follows in the wake of a number of months with record-beating temperatures in northern Siberia. The remote tundra lands located along the Arctic Ocean are now among the regions of the world with the quickest warming.

Map by NOAA

Maps from the U.S National Oceanic and Atmospheric Administration show deviation from normal temperatures of more than five degrees Celsius over major parts of Siberia.

The visualizations depict average temperature departures in the first four months of 2020 with respect to a 1981-2010 base period.

Nowhere else on the globe are the same kind of dark blood-red deviation as in Siberia.

The same maps are made available by Russia’s Meteorlogical Service, Roshydromet.

Five degrees warmer

The trend has been going on for many years. The latest climate report by Roshydromet says that average winter temperatures along the Northern Sea Route, the waters located along the country’s Arctic coast, have increased by about 5 degrees since the 1990s. And the warming is most significant in the areas around the Kara Sea, the report reads.

Heat wave runs across northern Siberia in May 2020. Map by Roshydromet

The extraordinarily heat continues into spring. Temperature maps from Roshydromet show that another heat wave in mid-May swept over the region. In parts of northern Siberia, including the remote Arctic peninsulas of Yamal, Gydan and Taymyr, the average temperature on the 23rd May were as much as 16 degrees Celsius higher than normal.

ADVERTISEMENT

The warm weather and early spring has created a record-early ice break-up of several of the great Siberian rivers, among them the Yenisey.

At the same time, the high temperatures have prepared the ground for unprecedentedly early wildfires. Authorities in the Yamal-Nenets region inform that they are already combating as many as seven fires.

Big change on tundra

The high temperatures have a major effects on ecosystems in the region. Researchers from the Tomsk State University have over the last years discovered that a big number of lakes on the Yamal-Nenets tundra have turned into wetlands.

“Normally, the formation of a drained lake is a pretty extensive and gradual process that takes several decades,” says head of research project Sergey Loiko. “But in this case, everything happens several ten times quicker,” he explains.

When a research team from the university was in the region in 2016, a lake disappeared in just few weeks, the university writes on its website.

The year 2016 is so far the warmest on record. But the following years have been only slightly colder. According to Roshydromet, 2019 was the second warmest year in the Arctic since measurements started in 1936.

The higher temperatures are accompanied by rapid growth of vegetation and greening of the region. This trend is very clear for indigenous peoples in the area, the researchers say.

Over the last decades they have seen a significant change of local bio diversity, the appearance of grass and new kinds of animals and insects.

Expansion of industry

The Arctic warming is evident also for the Russian shipping industry that over the last years has been able to make it across Arctic waters easier than any time before.

Supported by the lighter ice conditions in the area, ships in 2019 transported 31,5 million tons of goods on the Northern Sea Route, an increase of almost 60 percent from the previous year.

On 18th May, LNG carrier “Christophe de Margerie” set out from Arctic seaport Sabetta in Yamal with course for the eastern part of the Northern Sea Route. The eastbound voyage on the route is this year’s first of its kind and comes more than a month earlier than the previous years.

Few days later, the carrier was accompanied by sister ship “Vladimir Voronin”, that now is entering melting Arctic sea ice with course for China.

 


In these unsettling times, the Barents Observer needs your support more than ever. If you like what we’re doing, please consider making a donation. Your financial contributions, however big or small, will help keep our independent news coming from the north, about the north. 

From Norway you can VIPPS: 105792

Because of Rising CO2, Trees Might Be Warming the Arctic

Less water loss from plants causes the surrounding air to warm, and currents can transport that heat poleward

Because of Rising CO2, Trees Might Be Warming the Arctic
Credit: Adam Burton Getty Images

The Arctic is one of the fastest-warming places on the planet —and scientists still aren’t completely sure why.

Melting snow and ice may be speeding up the warming. Changes in atmospheric circulation could be playing a role. Many factors could be influencing the region’s temperatures, which are rising at least twice as fast as the rest of the world.

Now, scientists think they may have discovered an additional piece of the puzzle. Plants, it turns out, may have an unexpected influence on global warming.

ADVERTISEMENT

As carbon dioxide levels rise in the atmosphere, plants become more efficient at carrying out photosynthesis and other basic life functions. And they’re often able to save more water in the process.

Water that plants exchange with the air helps cool local temperatures. When they lose less water, their surroundings start to warm up.

study published last month in Nature Communications suggests that this process is helping to warm the Arctic.

“The influence of plants has been overlooked before,” said study co-author Jin-Soo Kim, a scientist at the University of Edinburgh, in an email to E&E News. “This study highlights the vegetation impacts on Arctic warming under [an] elevated CO2 world.”

The study used a suite of earth system models to arrive at its findings.

ADVERTISEMENT

The models suggest that rising CO2—the result of human greenhouse gas emissions—is causing plants to lose less water throughout the Northern Hemisphere, including densely vegetated regions in the tropics and the midlatitudes. This process causes temperatures in these places to warm even more than they would from climate change alone.

At the same time, large-scale atmospheric circulation patterns help transport heat between the tropics and the Arctic. The study suggests that this extra heat is warming the Arctic at an even faster rate.

In fact, the extra warming may actually contribute to other processes also speeding up Arctic climate change.

For instance, scientists believe that melting sea ice plays a big role in Arctic warming. Sea ice, with its bright, reflective surface, helps to beam sunlight away from the planet. As ice disappears, more sunlight —and more heat —is able to get through to the surface of the Earth.

The extra heat drifting up from the lower latitudes may be helping to melt sea ice at faster rates, the researchers suggest. And this, in turn, also contributes to faster Arctic warming.

ADVERTISEMENT

‘AN IMPORTANT UNKNOWN’

Overall, the study estimates that the plant effect may account for nearly 10% of the Arctic’s warming each year. And it could explain as much as 28% of the warming across the Northern Hemisphere’s lower latitudes.

But there’s still a lot of uncertainty about those estimates.

The scientists used an ensemble of eight models in their study and considered all the model results together. But from one model to the next, there are pretty large differences in the size of the plant effect.

That may be partly because the response of sea ice is still uncertain and tends to vary among different models.

But there’s also been some debate among scientists about the exact effect of rising CO2 on plants.

ADVERTISEMENT

Plants take in CO2, and also exchange water with the atmosphere, through tiny pores in their leaves called stomata. More CO2 means plants don’t have to keep their stomata open so wide. They can still get enough carbon dioxide through smaller openings, and they can save water in the process.

On the other hand, more CO2 can sometimes cause an increase in plant growth—and when there are more plants around, there’s more water being exchanged with the atmosphere.

These two effects—more plant growth, but also smaller stomata openings—can have conflicting effects on local temperatures.

For now, recent studies suggest that the stomata effect tends to win.

“I think it’s pretty clear that in many ecosystems, we actually don’t see as much plant growth as we sort of naively think we should by bumping up the CO2,” said Leander Anderegg, a postdoctoral researcher at the University of California, Berkeley, and the Carnegie Institution for Science who commented on the new research for E&E News. “And there, the increase in these plants using water more efficiently and closing stomata definitely offsets the growth aspect.”

ADVERTISEMENT

But, he added, the exact size of these effects is still uncertain and can vary from place to place.

“I think that it’s something that is pretty well-established that it’s sort of like an important unknown,” he said.

So scientists are still working to understand exactly how much influence plants have on the global climate. But other studies also suggest they may play an important role.

Previous research published in 2010 in the Proceedings of the National Academy of Sciences has found that the plant effect will increase global warming beyond what scientists would otherwise expect, based on climate change projections. Other studies, such as a 2018 analysis in Nature Communications, have suggested that the same effect will amplify extreme heat events, causing more frequent and more intense heat waves.

And still other studies have linked the plant effect to regional climate patterns in places outside the Arctic. For instance, one study published in Geophysical Research Letters in 2018 found that reduced water loss from plants may contribute to a drying pattern in the Amazon.

This is all an emerging area of research, with the exact magnitude of the effects still unclear. As a result, the effect is not well-represented —if at all —in most climate models.

According to Kim, that means there’s a chance that some model projections could be underestimating future climate change, particularly in the Arctic. More research may clarify whether that’s actually the case and exactly how much plants are contributing to the warming that’s happening all over the globe.

For now, the fact that many studies with many models all seem to be converging on the same basic idea gives scientists more confidence that they’re on the right track, Anderegg said.

“And even if we have some amazing breakthroughs in how we model plants … I think what’s absolutely durable about the paper is how plants respond to CO2 isn’t gonna save us,” he added.

Reprinted from Climatewire with permission from E&E News. E&E provides daily coverage of essential energy and environmental news at www.eenews.net.

It Hit 80 Degrees in the Arctic This Week

This story will provide important context for the headline, and I encourage you to read it—but really, the headline tells you what you need to know: It was 80 degrees Fahrenheit above the Arctic Circle this week.

A little farther south, in Siberia—you know, the region of world we reference when we want to connote something cold—it was 86 degrees Fahrenheit. Arctic sea ice in the neighboring Kara Sea took the deepest May nose dive ever recorded. Oh, and random swaths of the region are on fire. Things are extremely wrong.

Let’s start with the heat above Arctic Circle. Mika Rantanen, a researcher at the Finnish Meteorological Institute, flagged a map showing blistering heat across western Siberia. The region has been the epicenter of an explosive heat wave that has rippled across the Arctic this week. Models forecast temperatures there will be as much as 36 degrees Fahrenheit above normal for this time of year. The heat could break a bit by the middle of next week, but widespread warmth will continue to grip the region.

“The primary reason for the heat is a so called upper-level ridge, am omega-shaped high pressure system which allows clear skies and sinking air motion,” Rantanen told Earther in a Twitter direct message. “However, what I think is the most noteworthy aspect is that that particular area in Russia has been record-warm in winter. So I believe that lack of snow can play a role as the heat us not consumed into melting of snow.”

On land, it means wildfires continue to spread. Pierre Markuse, a satellite monitoring expert, has kept an eye on the series of increasingly odd fires above the Arctic Circle, a place known more for ice than fire. Most of the blazes he’s documented are in the eastern portion of Siberia, which also dealt with its fair share of heat all year in addition to low snowpack. Seeing fires burn next to braided rivers and large patches of unmelted snow is truly a mood for our current era of climate destabilization.

Totally cool and normal fire burning above the Arctic Circle.
Totally cool and normal fire burning above the Arctic Circle.
Image: Pierre Markuse (Flickr)

Then there are the ocean impacts, because climate change doesn’t just stop at the water’s edge. Warmth has washed over the seas that border Siberia, and the Kara Sea north of the western part of the region has seen the most precipitous decline in sea ice. After a slow decline in the first part of May, warm air has fueled a stark decline in sea ice. As of earlier this week, ice extent was the lowest level that’s ever been record in May. It stands as a stark outlier, especially when looking at how ice behaved in the 1980s. I’m old enough to remember when the ice in the Kara Sea used to decline in July.

Numerous other seas that ring the Arctic have also been losing ice. And while they’re not at record-setting levels like the Kara Sea, the Bering and Barents Seas are both at some of their lowest levels on record for this time of year.

These impacts are the latest in a litany of climate horrors for the Arctic as a whole. Last summer, it reached nearly 95 degrees Fahrenheit above the Arctic Circle in Sweden. The same summer, the mercury hit 70 degrees Fahrenheit at the northernmost settlement on the planet. Greenland also melted and burned. That’s just some of what happened last year. I could list the same for 2018. And 2017. And you get the point.

I have to be honest. I’m getting sick of writing these stories. The Arctic is warming twice as fast as the rest of the globe, and what’s happening there is unprecedented. But how many ways can you talk about the fact that the Arctic is just extremely, massively fucked by climate change when the impacts are relentless? After a while, the degrees above normal start to feel normal, and the records are ephemeral, set to broken again the next year.

But here we are with just another absolutely outlandish occurrence. I’ll keep writing about them, because even if the records start to blend together, that in itself is a sign we really need to get our shit together and cut emissions now.

Update May 22, 11:25 a.m.: Mika Rantanen’s comments have been added to this post.

Polar vortex whips millions of Americans with strong winds, record lows and even snow

(CNN)More than 100 million Americans will see temperatures drop below freezing this weekend, a harsh contrast to last week’s sunny weather.

Saturday started with a tied record for the latest snowfall in New York City’s Central Park, with light snow reported by the National Weather Service.
The NWS tweeted: “Snow in Central Park! In May! The Central Park Automated Surface Observing System (ASOS) recorded snow. This ties the record latest snow set on this day in 1977.”
Central Park on Saturday morning also hit a daily record low of 34 degrees Fahrenheit.
The white stuff also fell overnight in Pennsylvania and upstate New York, and continued Saturday in Vermont, New Hampshire, Massachusetts and Maine. Shaftsbury, Vermont, got 9 inches, the National Oceanic and Atmospheric Administration reported.
At least 20 states were under a frost or freeze watch, warning or advisory on Saturday morning. Although most of those states are in the Midwest or Northeast, the advisories stretch all the way down to Georgia and South Carolina.

In some Northeast states, it felt more like early March than May. A system that began in the Great Lakes region was set to bring gusty winds and 6 to 12 inches of wet snow to New England.
“It appears that interior New England will see significant amounts of wet snow with northerly winds becoming increasingly strong and gusty late Friday night into Saturday morning,” the Weather Prediction Center said.
For cities like New York, Albany and Hartford, cold rain will be the main focus, but some snow could mix in.

Blame the polar vortex

More than 40 cities across the Midwest and Northeast set daily low temperature records Saturday morning, including Pittsburgh at 28 degrees and Baltimore at 34.
For Fort Wayne, Indiana, it was also the coldest temperature ever recorded so late in the season and the coldest temperature recorded in May, in addition to a daily record low (23 degrees).
The polar vortex was so strong this winter and spring that it led to the largest-ever Arctic ozone hole, but not a lot of cold weather.
The polar vortex, as its scary name suggests, is a circulation of strong, upper-level winds that normally surround the northern pole, moving in a west to east direction — a polar low-pressure system.
These winds tend to keep the bitter cold air locked in the Arctic regions of the Northern Hemisphere. On occasion, the vortex can become distorted and dip further south, allowing cold air to spill southward.
But it didn’t spill out into the US this winter. That’s why the spring and winter have been mild and major East Coast cities saw low snowfall amounts.
Now the polar vortex is weakening, allowing Arctic air to spill out — leading to plunging temperatures in the East this weekend.

Arctic will see ice-free summers by 2050 as globe warms, study says

Doyle Rice

USA TODAY
  • Sea ice is frozen ocean water that melts each summer, then refreezes each winter.
  • Sea ice affects Arctic communities and wildlife such as polar bears and walruses.
  • As the climate changes, the Arctic is warming more than twice as fast as the rest of the planet.

The Arctic Ocean will be ice-free in the summer within the next 30 years, a study says, which will result in “devastating consequences for the Arctic ecosystem,” according to McGill University in Montreal.

Sea ice is frozen ocean water that melts each summer, then refreezes each winter. The amount of summer sea ice in the Arctic has been steadily shrinking over the past few decades because of global warming. Since satellite records began in 1979, summer Arctic ice has lost 40% of its area and up to 70% of its volume, the Guardian said.

In fact, it reached its second-smallest level on record in 2019, the National Oceanic and Atmospheric Administration said.

Sea ice affects Arctic communities and wildlife such as polar bears and walruses, and it helps regulate the planet’s temperature by influencing the circulation of the atmosphere and ocean. It also affects global weather patterns.

“While the Arctic sea ice extent is decreasing during this transition to an ice-free Arctic, the year-to-year variability in extent greatly increases, making life more difficult for local populations and ice-dependent species,” said study co-author Bruno Tremblay of the department of atmospheric and oceanic sciences at McGill.

‘Polar bears may disappear’: Arctic sea ice keeps shrinking. Here’s what that means for the planet

As the climate changes, the Arctic is warming more than twice as fast as the rest of the planet. Arctic air temperatures were about 3.4 degrees above average in 2019 and were the second-warmest since records began in 1900.

Polar bears walk on Arctic sea ice. Sea ice cover is a hunting ground and habitat for polar bears and seals, and keeps the Arctic cool by reflecting sunlight.

How often the Arctic loses its sea ice cover in the future depends on emissions of carbon dioxide, the study said. If emissions are reduced rapidly, ice-free years will occur only occasionally. With higher emissions, the Arctic Ocean will become ice-free in most years.

Thus, even if humans act to reduce emissions dramatically, summer sea ice might still be gone, according to the study.

Sea ice melting:Rising Arctic temps cause sea ice to melt at alarming level, threatening habitats and cultures

“If we reduce global emissions rapidly and substantially, and thus keep global warming below 2 degrees Celsius relative to pre-industrial levels, Arctic sea ice will nevertheless likely disappear occasionally in summer even before 2050,” said study lead author Dirk Notz, who heads the sea ice research group at the University of Hamburg in Germany. “This really surprised us.”

The study analyzed recent results from 40 of the latest climate computer models and involved 21 research institutes from around the world. It was published in the journal Geophysical Research Letters, a publication of the American Geophysical Union.

Abrupt Warming – How Much And How Fast?

SATURDAY, MAY 13, 2017

https://arctic-news.blogspot.com/2017/05/abrupt-warming-how-much-and-how-fast.html

How much could temperatures rise? As the image shows, a rise of more than 10°C (18°F) could take place, resulting in mass extinction of many species, including humans.

How fast could such a temperature rise eventuate? As above image also shows, such a rise could take place within a few years. The polynomial trend is based on NASA January 2012-February 2017 anomalies from 1951-1980, adjusted by +0.59°C to cater for the rise from 1750 to 1951-1980. The trend points at a 3°C rise in the course of 2018, which would be devastating. Moreover, the rise doesn’t stop there and the trend points at a 10°C rise as early as the year 2021.

Is this polynomial trend the most appropriate one? This has been discussed for years, e.g. at the Controversy Page, and more recently at Which Trend Is best?

The bottom part of above image shows the warming elements that add up to the 10°C (18°F) temperature rise. Figures for five elements may be overestimated (as indicated by the ⇦ symbol) or underestimated (⇨ symbol), while figures in two elements could be either under- or overestimated depending on developments in other elements. Interaction between warming elements is included, i.e. where applicable, figures on the image include interaction based on initial figures and subsequently apportioned over the relevant elements.

A closer look at each of these warming elements further explains why abrupt warming could take place in a matter of years. As far as the first two elements are concerned, i.e. the rise from 1900 and the rise from 1750 to 1900, this has already eventuated. The speed at which further warming elements can strike is depicted in the image below, i.e. the rise could for a large part occur within years and in some cases within days and even immediately.

Assessing the Danger

The danger can be looked at on three dimensions: timescale, probability and severity. On the severity dimension, a 10°C temperature rise is beyond catastrophic, i.e. we’re talking about extinction of species at massive scale, including humans. On the probability dimension, the danger appears to be progressing inevitably toward certainty if no comprehensive and effective action is taken.

In terms of timescale, a 10°C temperature rise could eventuate within a matter of years, which makes the danger imminent, adding further weight to the need to start taking comprehensive and effective action, as described in the Climate Plan.

The Threat

With little or no action taken on global warming, it appears that the Antropocene will lead to extinction of the very human beings after which the era is named, with the Anthropocene possibly running from 1950 to 2021, i.e. a mere 71 years and much too short to constitute an era. In that case a better name for the period would be the Sixth Extiction Event, as also illustrated by the image below.

[ See: Feedbacks in the Arctic and the Extinction page ]

In conclusion, it’s high time that homo sapiens starts acting as genuinely wise modern human beings and commit to comprehensive and effective action as discussed at the Climate Plan.

Further reading

Read more about the threat here. Warming elements are discussed in more detail at the Extinction Page, while specific elements are also discussed in posts, e.g. methane hydrates are discussed at Methane Erupting From Arctic Ocean, decline of the snow and ice cover and associated feedbacks is discussed at Arctic Ocean Feedbacks and less take-up by oceans of CO₂ and heat from the atmosphere is discussed at 10°C or 18°F warmer by 2021? and at the new post High Waves Set To Batter Arctic Ocean.

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

• Feedbacks
https://arctic-news.blogspot.com/p/feedbacks.html

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

• The Threat
https://arctic-news.blogspot.com/p/threat.html

• Controversy
https://arctic-news.blogspot.com/p/controversy.html

• Which Trend Is best?
https://arctic-news.blogspot.com/2017/03/which-trend-is-best.html

• 10°C or 18°F warmer by 2021?
https://arctic-news.blogspot.com/2017/04/10c-or-18f-warmer-by-2021.html

• Arctic Ocean Feedbacks
https://arctic-news.blogspot.com/2017/01/arctic-ocean-feedbacks.html

• Methane Erupting From Arctic Ocean
https://arctic-news.blogspot.com/2017/03/methane-erupting-from-arctic-ocean-seafloor.html

• High Waves Set To Batter Arctic Ocean
https://arctic-news.blogspot.com/2017/06/high-waves-set-to-batter-arctic-ocean.html

• Warning of mass extinction of species, including humans, within one decade
https://arctic-news.blogspot.com/2017/02/warning-of-mass-extinction-of-species-including-humans-within-one-decade.html

2°C crossed

FRIDAY, MARCH 13, 2020

https://arctic-news.blogspot.com/2020/03/2c-crossed.html

It’s time to stop denying how precarious the situation is.

Remember the Paris Agreement? In 2015, politicians pledged to hold the global temperature rise to well below 2°C above pre-industrial levels and pledged they would try and limit the temperature rise to 1.5°C above pre-industrial levels. Well, an analysis by Sam Carana shows that it was already more than 1.5°C above pre-industrial when the Paris Agreement was reached.

In Sam Carana’s analysis, the year 1750 is used as the baseline for pre-industrial. The analysis shows that we meanwhile have also crossed the 2°C threshold (in February 2020) and that the temperature rise looks set to rapidly drive humans and eventually most if not all species on Earth into extinction.

Yet, our politicians refuse to act!

Accelerating temperature rise

Indeed, there are indications that the recent rise is part of a trend that points at even higher temperatures in the near future, as also discussed at this analysis page. Polynomial trends can highlight such acceleration better than linear trends. The 1970-2030 polynomial trend in the image below is calculated over the period from 1880 through to February 2020. The trend points at 3°C getting crossed in 2026.

In above image, the January 2020 and February 2020 anomalies are above the trend. This indicates that the situation might be even worse.

A polynomial trend calculated over a shorter period can highlight short-term variation such as associated with El Niño events and can highlight feedbacks that might otherwise be overlooked. The 2010-2022 trend in the image below is calculated with 2009-Feb.2020 data. The trend indicates that 2°C was crossed in February 2020, and looks set to keep rising and cross 3°C in 2021, more specifically in January next year, which is less than a year away.

Such a steep rise is in line with unfolding developments that are causing the aerosol masking effect to fall away, such as a decrease in industrial activity due to COVID-19 fears. The image below shows a potential rise of 18°C or 32.4°F from 1750 by the year 2026.

Above image was posted more than a year ago and illustrates that much of this potentially huge temperature rise over the next few years could eventuate as a result of a reduction in the cooling now provided by sulfates. In other words, a steep temperature rise could result from a decline in industrial activity that is caused by fears about the spread of a contagious virus, as also discussed in the video at an earlier post.

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

Links

• Analysis: Crossing the Paris Agreement thresholds
https://arctic-news.blogspot.com/p/crossing.html

• A rise of 18°C or 32.4°F by 2026?
https://arctic-news.blogspot.com/2019/02/a-rise-of-18c-or-324f-by-2026.html

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

• Arctic Ocean January 2020
https://arctic-news.blogspot.com/2020/02/arctic-ocean-february-2020.html

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

In the video below, Guy McPherson discusses the situation.

Intensity of past methane release measured with new, groundbreaking methods


March 30, 2020
Source:
CAGE – Center for Arctic Gas Hydrate, Climate and Environment
https://www.sciencedaily.com/releases/2020/03/200330093427.htm
Summary:
A novel approach to geochemical measurements helps scientists reconstruct the past intensity of the methane seeps in the Arctic Ocean. Recent studies show that methane emissions fluctuated, strongly, in response to known periods of abrupt climate change at the end of the last glacial cycle.
Share:
FULL STORY

Past records of methane release are crucial for understanding future climate changes. Methane is a potent greenhouse gas, that has had significant impact on climate changes in the geological past.

“Previously, when dating the natural release of methane, we used to measure mostly carbon isotopes. But now we know that carbon isotopes alone can’t tell us the full story of past emissions of this greenhouse gas.” says professor Giuliana Panieri, from CAGE Centre for Arctic Gas Hydrate, Environment and Climate at UiT The Arctic University of Norway.

Professor Panieri is a micropaleontologist and co-author of a new study in Scientific Reports showing a new approach to geochemical measurements.

Geological detective work

Measuring carbon isotopes is a very important method within climate sciences. Carbon, found in all living things, is absorbed over time in a particular fashion by organisms in nature. For instance, carbon found in methane (CH4) in the ocean, is absorbed in the shells of tiny organisms called foraminifera, leaving isotopic clues.

Foraminifera, found in all of the world’s oceans, are excellent carriers of information. They inhabit methane seeps and their shells are preserved as fossils in ocean sediments.

Through some geochemical detective work, and a mass spectrometer, scientists can interpret the amounts of the carbon isotope δ13C in the shells and reconstruct past methane emissions. If δ13C values in the fossilized shells are depleted the methane was present in the environment when the shell was deposited.

Carbon isotope measurements are the most frequently used method, but new technologies make new geochemical components possible to measure, giving climate scientists new tools.

How intense was the release?

The study in Scientific Reports highlights the potential of sulfur isotopic signature (δ34S) in foraminifera, as a novel tool for reconstructing the intensity of CH4 emissions in geological records. This can also, indirectly, help date the release.

“This is the first time that sulfur isotopes are measured in foraminiferal shells from methane seeps. The samples were collected from a well-known site of present-day methane release, Vestnesa Ridge. Here, gas has been seeping into the ocean at least from the Last Glacial Maximum: some 20,000 to 5,000 years ago.” says Panieri.

“How did methane in the sub-seabed respond to previous global warmings? Was it merely bubbling up, or was it released in a constant and abrupt jet, strongly emitted into the water column?”

These questions are important in the provinces of large gas hydrate accumulations, such as Vestnesa Ridge.

Gas hydrate is an icy form of methane, trapped in a cage of frozen water and kept contained in the ocean sediments in low temperatures and under high pressure. However, hydrates are susceptible to melting if these conditions are not met — for example, if the ocean temperature changes due to the warming of the waters. The stability of gas hydrates is under intense investigation because of the possible effects of climate change on gas hydrate dissociation.

“The combination of carbon, oxygen, and sulfur isotopes found in foraminifera allows us to reconstruct the flux of methane released in the geological past. This represents a fundamental advancement in studies of past climate. It offers the opportunity to study the connection between methane seepage, climate, and underlying tectonic processes with a new degree of confidence.” Says Chiara Borrelli, first author of the study and researcher at Department of Earth and Environmental Sciences, University of Rochester, USA.

“Our study shows that there was a strong methane fluctuation at the sampling site, responding to known periods of abrupt cooling and warming, at the end of the last glacial cycle.”

What was the source of methane?

Carbon isotopes can tell scientists whether methane was present in the water column at a certain time. But they cannot tell them if the methane was released from melting hydrates. However, the traces of oxygen isotopic signature δ18O in benthic foraminifera can, as shown in a newly published study by Dessandier et al. in Geo-Marine letters.

“If we have a large amount of δ18O in the foraminiferal shells, we can say that the source of methane is the gas hydrate dissociation,” says Panieri, who also co-authored this paper.

“We found a significant enrichment of δ18Oin all foraminifera samples characterized by depleted δ13C. These results mainly come from the precipitation of authigenic carbonates around the foraminiferal shells, so-called secondary overgrowth. These methane-derived carbonates are characterized by a heavy oxygen isotopic signature. This signature can only be explained by dissociation of gas hydrates because gas hydrates are naturally enriched in 18O due to their ice-like physical properties.” according to Pierre-Antoine Dessandier, a postdoc at CAGE and first author of the study.

Dessandier points out that both δ13C and δ18O clues have to be followed, to decipher the dynamic and the source of the methane release from the Arctic Ocean floor.

Groundbreaking methods from the natural Arctic laboratory

Vestnesa Ridge is a very well-investigated site of methane release, a laboratory for modern-day release of methane from gas hydrates, but also for micropaleontology. It is one of the major sites of research for CAGE.

The exhaustive research on the site has resulted in many scientific breakthroughs in micropaleontology.

“Consider secondary overgrowth on foraminiferal shells: It is a minuscule carbonate deposit. Before CAGE it was considered to be a contaminant in the samples. But new technology opens new doors. We have discovered that the presence of the secondary overgrowth in itself is an indicator of methane release. Something that previously was considered an interference, and caused samples to be thrown out with the thrash, is, in reality, an unknown book, containing enormous amounts of information in itself.” says Panieri.

The new geochemical measurement methods are now added to the toolbox for future micropaleontological research.

“The new isotopic measurements give us a possibility to investigate questions regarding climate change that we today don’t even know that we need to ask. The methods can be applied on both secondary overgrowth and shells themselves, and will be enormously important in future research.”


Story Source:

Materials provided by CAGE – Center for Arctic Gas Hydrate, Climate and Environment. Original written by Maja Sojtaric. Note: Content may be edited for style and length.

Arctic may see ice-free summers in as few as 15 years, study says

Summers may be ice-free in the Arctic as soon as 2034, a new study suggests.

  • Sea ice is frozen ocean water that melts each summer, then refreezes each winter.
  • The Arctic is warming more than twice as fast as the rest of the planet.
  • The study used statistical models to predict the future amount of Arctic ice.

Climate change is taking its toll on one of the world’s coldest places.

study suggests that the Arctic “may be essentially ice-free during summer within 15 years.”

The study used statistical models to predict the future amount of Arctic ice, which suggested that the Arctic could be ice-free in the summer during the decade of the 2030s – most likely in the year 2034.

Sea ice is frozen ocean water that melts each summer, then refreezes each winter. The amount of summer sea ice in the Arctic has been steadily shrinking over the past few decades because of global warming. It reached its second-smallest level on record in 2019, the National Oceanic and Atmospheric Administration (NOAA) said.

Sea ice affects Arctic communities and wildlife such as polar bears and walruses, and it helps regulate the planet’s temperature by influencing the circulation of the atmosphere and ocean.

“The extent of Arctic ice is important to Arctic peoples, whose lands are being affected by increased coastal erosion,” NOAA said in a statement. “Conversely, the disappearance of ice creates economic opportunities, including the opening of oil fields and new shipping routes.”

It also affects global weather patterns.

‘Polar bears may disappear:Arctic sea ice keeps shrinking. Here’s what that means for the planet

The study was conducted by scientists at NOAA, the University of Washington, and the North Carolina Institute for Climate Studies.

What scientists refer to as the first “ice-free” Arctic summer year will occur when the Arctic has less than 1 million square kilometers of sea ice. (The thick ice sheets surrounding Canada’s Arctic islands are likely to remain for much longer, even in summer.)

As the climate changes, the Arctic is warming more than twice as fast as the rest of the planet: In fact, Arctic air temperatures were about 3.4 degrees above average in 2019, and were the second-warmest since records began in 1900.

Scientists also said the results of the study indicate that there is room for improvement in sea-ice models – and that the ice may disappear even more quickly than current models suggest.

“Climate models may be collectively underestimating the rate of change,” the authors write in the study.

The study was published in the journal Climate.

Discovery Regarding Arctic Sea Ice and Permafrost Has Significant Implications for the Future

Siberian Cave

Researchers gathering data in a Siberian cave. Credit: University of Oxford

https://scitechdaily.com/discovery-regarding-arctic-sea-ice-and-permafrost-has-significant-implications-for-the-future/

Sea-Ice-Free Arctic Makes Permafrost Vulnerable to Thawing

Permafrost is ground that remains frozen throughout the year; it covers nearly a quarter of Northern Hemisphere land. The frozen state of permafrost enables it to store large amounts of carbon; about twice as much as in the atmosphere. The rate and extent of future thawing of permafrost, and consequent release of its carbon, is hard to predict from modern observations alone.

However, a crucial past relationship between summer sea ice in the Arctic and permafrost, discovered in this study, is now understood, with significant implications for the future.

Professor Gideon Henderson, an author of the study based at the Department of Earth Sciences, University of Oxford, said: ‘We were surprised to find that times when permafrost melted in the past did not simply match up with times when the Earth was at its warmest, but were much more likely when the Arctic was free of ice in the summer. This discovery about the past behavior of permafrost suggests that the expected loss of Arctic sea ice in the future will accelerate melting of the permafrost presently found across much of Siberia.’

Significant decreases of Arctic sea ice have been observed in recent years, and the Arctic is expected to be free of summer sea ice in the coming decades. Such loss of sea ice is likely to lead to an acceleration of thawing of permafrost in Siberia and to the consequent release of carbon.

The new research relies on challenging field work to discover and explore Siberian caves. Caves are powerful recorders of periods when permafrost was absent in the past. Stalagmites, stalactites and flowstones can only form when there is liquid water, and therefore not when overlying land is permanently frozen. The presence of stalagmites in caves under present permafrost thus demonstrate periods when permafrost was absent in the past.

Development of new approaches to date stalagmites using measurements of natural uranium and lead, allow dating of the recovered stalagmites — and therefore of periods of permafrost absence — for the last one and a half million years. Stalagmites grew intermittently from 1,500,000 to 400,000 years ago, and have not grown for the last 400,000 years. The timing of stalagmite formation, and therefore absence of permafrost, do not relate simply to global temperatures in the past but are notably more common when the Arctic Ocean was free of summer sea-ice.

This study shows that several processes may lead to the relationship between Arctic sea-ice and permafrost. The absence of sea ice leads to an increase in heat and moisture transfer from ocean to atmosphere and therefore to warmer air transported far overland into Siberia. Moisture transport also increases snow fall over Siberia during the autumn months. This blanket of snow insulates the ground from the extreme cold of winters leading to an increase in average annual ground temperatures, destabilizing the permafrost. Consequently, in regions with increased snow cover and insulation, permafrost will start to thaw, releasing carbon dioxide that was trapped for millennia.

Reference: “Palaeoclimate evidence of vulnerable permafrost during times of low sea ice” by A. Vaks, A. J. Mason, S. F. M. Breitenbach, A. M. Kononov, A. V. Osinzev, M. Rosensaft, A. Borshevsky, O. S. Gutareva and G. M. Henderson, 8 January 2020, Nature.
DOI: 10.1038/s41586-019-1880-1

The international team involved in the study consists of scientists from the Geological Survey of Israel, The University of Oxford, UK, Northumbria University, UK, The Institute of Earth’s Crust of the Russian Academy of Sciences (Irkutsk, Russia), and the Speleoclub Arabica (Irkutsk, Russia).