Greenland and Global Update from Jason Box

July 30, 2021

Guardian:

Greenland’s vast ice sheet is undergoing a surge in melting, with the amount of ice vanishing in a single day this week enough to cover the whole of Florida in two inches of water, researchers have found.

The burst of melting has reached deep into Greenland’s enormous icy interior, with data from the Danish government showing that the ice sheet lost 8.5bn tons of surface mass on Tuesday alone. A further 8.4bn tons was lost on Thursday, the Polar Portal monitoring website reported.

The scale of disappearing ice is so large that the losses on Tuesday alone created enough meltwater that it would drown the entire US state of Florida in two inches, or 5cm, of water. Ice that melts away in Greenland flows as water into the ocean, where it adds to the ongoing increase in global sea level caused by human-induced climate change.

“It’s a very high level of melting and it will probably change the face of Greenland because it will be a very strong driver for an acceleration of future melting, and therefore sea-level rise,” said Marco Tedesco, a glacier expert at Columbia University and adjunct scientist at Nasa.

Tedesco said a patch of high pressure is sucking and holding warmer air from further south “like a vacuum cleaner” and holding it over eastern Greenland, causing an all-time record temperature of 19.8C in the region on Wednesday. As seasonal snow melts away, darker core ice is exposed, which then melts and adds to sea level rise.

“We had these sort of atmospheric events in the past but they are now getting longer and more frequent,” Tedesco said.

“The snow is like a protective blanket so once that’s gone you get locked into faster and faster melting, so who knows what will happen with the melting now. It’s amazing to see how vulnerable these huge, giant areas of ice are. I’m astonished at how powerful the forces acting on them are.”

43 Responses to “Greenland and Global Update from Jason Box”

  1. jimbills Says:

    Two articles in WP today:

    Heat waves to drastically worsen in Northern Hemisphere, studies warn
    https://www.washingtonpost.com/weather/2021/08/03/heat-wave-stress-climate-change/

    Scientists expected thawing wetlands in Siberia’s permafrost. What they found is ‘much more dangerous.’
    https://www.washingtonpost.com/climate-environment/2021/08/02/climate-change-heat-wave-unleashes-methane-from-prehistoric-siberian-rock/

    • redskylite Says:

      Thanks for sharing JimBills, unfortunately the Washington Post now demands subscription to enjoy the article, as a pensioner enduring rapid inflation at the moment I am reluctant to subscribe. There was an interesting WAPO headline a few days ago regarding the jet stream (from The Weather Gang), as this is an area of debate at the moment, I am very curious to know what Bob Henson said about the jet stream from the latest research, but will have to wait until it spreads to the free press.

      vive la presse libre

      =======================

      “The jet stream is always moving and it does every year but climate change has definitely helped to shift some of the weather patterns we have seen. Theres definitely been shifts n terms of the weather that have been driven by climate change.”

      https://inews.co.uk/news/uk/uk-weather-why-so-bad-rain-august-when-improve-just-stream-climate-change-1133548

      • redskylite Says:

        “Brown bears are pushed out of their natural habitat by raging wildfires; local drivers share videos of brown bear families begging for food along the roads. No estimate yet on the damage to other wildlife has been given.

        https://siberiantimes.com/other/others/news/apocalypse-in-yakutia-russias-coldest-region-as-noxious-smog-from-wildfires-blocks-sun/

      • jimbills Says:

        Key parts #1:

        In a study published last week in Nature Climate Change, Fischer and his colleagues ran nearly 100 computer simulations to determine the frequency and intensity of record-breaking heat waves with future projections of Earth’s climate. They defined the intensity of the events by the margin by which they broke previous records.

        They found week-long record-breaking heat events were up to seven times more likely to occur from 2021 to 2050. From 2051 to 2080, these events were up to 21 more times likely to occur and could happen every six to 37 years somewhere in the northern midlatitudes. These events would break previous heat records by 6.4 to 7.6 degrees Fahrenheit (3.6 to 4.2 Celsius).

        Heat stress is one of the most serious effects of extreme heat events on the human body. It occurs when temperatures and relative humidity are high enough that the body can no longer get rid of the extra heat and cool itself. Heat stress can lead to heat exhaustion, heat cramps, heat strokes and death.

        In a study published in the journal Earth’s Future in April, a team of researchers investigated how heat stress would intensify along with general increases in temperature, relative humidity and population in the Lower 48 U.S. states over the next century.

        They found the potential impact of heat stress of short- to medium-duration (one to seven days) is likely to double in the United States by 2060 to 2099, if greenhouse gas emissions continue to be high. The risk tripled, though, in places with heavier populations, such as Central California, the Pacific Northwest and the Great Lakes region.

      • jimbills Says:

        Key part #2:

        Scientists have long been worried about what many call “the methane bomb” — the potentially catastrophic release of methane from thawing wetlands in Siberia’s permafrost.

        But now a study by three geologists says that a heat wave in 2020 has revealed a surge in methane emissions “potentially in much higher amounts” from a different source: thawing rock formations in the Arctic permafrost.

        The difference is that thawing wetlands releases “microbial” methane from the decay of soil and organic matter, while thawing limestone — or carbonate rock — releases hydrocarbons and gas hydrates from reservoirs both below and within the permafrost, making it “much more dangerous” than past studies have suggested.

        Nikolaus Froitzheim, who teaches at the Institute of Geosciences at the University of Bonn, said that he and two colleagues used satellite maps that measured intense methane concentrations over two “conspicuous elongated areas” of limestone — stripes that were several miles wide and up to 375 miles long — in the Taymyr Peninsula and the area around northern Siberia.

        The study was published by the Proceedings of the National Academy of Sciences.

        Surface temperatures during the heat wave in 2020 soared to 10.8 degrees Fahrenheit above the 1979-2000 norms. In the long stripes, there is hardly any soil, and vegetation is scarce, the study says. So the limestone crops out of the surface. As the rock formations warm up, cracks and pockets opened up, releasing methane that had been trapped inside.

        — ends with “needs more study” to confirm

      • jimbills Says:

        Probably uncool to do this – apologies to Peter if so – but here’s the whole article you mentioned from Weather Gang. It’s interesting. On Texas, a personal note on that – the Dallas area has a very mild winter, even for here, for the entire winter in the run up to the Valentine’s Day event:

        ———————————————–

        An influential, highly publicized theory — that a warming Arctic is causing more intense winter outbreaks of cold and snow in midlatitudes — is hitting resistance from an ongoing sequence of studies, including the most comprehensive polar modeling to date.

        The idea, first put forth in a 2012 paper by Jennifer Francis, now at the Woodwell Climate Research Center, and Stephen Vavrus, at the University of Wisconsin at Madison, is that two well-established trends — Arctic amplification (intensified global warming at higher latitudes) and depleted sea ice — can force the polar jet stream to dip farther south, thus causing more intense bouts of winter weather than might have otherwise occurred.
        Over the past decade, this hypothesis sparked widespread public interest and scientific debate, as various high-profile cold waves and snow onslaughts hit North America and Eurasia, including a deadly, prolonged cold wave in Texas last February.

        Texas officials question the state’s power grid system after deadly winter storm

        The Texas power grid failure that left millions without power during the week of Feb. 15 prompted calls for a system more resilient to extreme weather. (The Washington Post)

        Winter temperatures over the past three decades have shown cooling in some areas of the northern midlatitudes, especially eastern Asia.

        But the cooling has been far from ubiquitous and the Arctic-midlatitude link has been difficult to detect in simulations by global computer models. Instead, the models point more strongly toward the gradual, longer-term trend of milder midlatitude winters that one would expect in a human-warmed climate. (A separate line of research is addressing extremes during the summer, such as the unprecedented heat wave that struck the Pacific Northwest in June; see below.)

        Some emerging work, not yet peer-reviewed, does reveal faint fingerprints of the Francis-Vavrus hypothesis in new simulations of Arctic and midlatitude winter climates, part of the Polar Amplification Model Intercomparison Project (PAMIP).

        “It does look like there’s something there, but it looks fairly weak,” James Screen, a climate scientist at the University of Exeter, said in an interview. “That doesn’t mean it’s not one part of the overall jigsaw.”

        “There’s genuine reason to be concerned about climate change and its effects,” Screen added, “but an increase in the frequency in cold events would not be at the top of my list.”

        Screen has published several related studies with Russell Blackport, now at Environment and Climate Change Canada, over the past two years. The title of one of their latest, published in April in the Journal of Climate, is itself an assertion: “Observed Statistical Connections Overestimate the Causal Effects of Arctic Sea Ice Changes on Midlatitude Winter Climate.”
        In this study and others, Screen and Blackport suggest that the connection between Arctic sea ice loss and extreme midlatitude events is real, but not necessarily causal. Instead, they argue, a third factor — most likely large-scale changes in atmospheric circulation that may not be permanent — is probably driving both the sea ice loss and the extreme winter events.
        Francis asserts that the new PAMIP work actually lends support to some of the building blocks of her hypothesis, even if the model findings aren’t as strong as recent observations: “The jet stream shifted southward, just like we expect to see as the Arctic warms,” Francis said in an interview. “The zonal [west-to-east] winds were weaker when there was less sea ice. All these things we’ve been talking about for almost 10 years, they found in their models.”

        At the same time, Francis maintains that global models can’t fully replicate the Arctic-midlatitude connection simply by adding or removing sea ice, especially if the results lump together conditions across a whole winter or the entire midlatitudes.

        “If you’re interested in things like whether the jet stream is going to get wavier, whether you’re going to get more extreme weather events, more blocking — these are all very regional, short-term responses,” Francis said.
        Francis also points to work led by Zachary Labe of the University of California at Irvine, which published in August 2020 in Geophysical Research Letters. Labe and colleagues found that when they modeled not only sea ice loss but also the deep warming observed in the Arctic atmosphere, then a distinct pattern emerged, with a stronger Siberian High and colder winter temperatures across eastern Asia.

        As it happens, eastern Asia is one of the few regions on Earth where winters have trended cooler over the past several decades. The winter of 2020-21 was colder than the 1981-2010 average across most of Russia and northern Asia.

        Like Francis, Screen is intrigued by the Labe paper: “It’s interesting, but I’m not entirely convinced — I’d like to see that result confirmed in other studies.”

        The appeal of a counterintuitive idea

        With mountains of research pointing to so many dire consequences of human-caused climate change — some of them already taking shape, such as the ominous growth of “hot droughts” in the U.S. Southwest — it’s easy to see how winter storms and cold blasts could be accepted as just another negative outcome, albeit a freakish one.

        “The generalization that climate change makes extreme weather worse causes people to assume it makes all extreme weather worse,” said Texas state climatologist John Nielsen-Gammon. He’s now analyzing the extreme cold and snow that paralyzed his state in February. No studies have yet tried to directly attribute any or all of the Texas event to climate change.
        While the cold blast was on par with some of the worst in Texas history, the catastrophic consequences — close to 150 deaths and $20 billion in damage, according to reinsurance broker Aon — were widely considered to be the result of the state’s main power grid operator, ERCOT, being unprepared for such high-end events in a fast-growing region.

        Nielsen-Gammon found that the statewide average temperature, weighted by population within the ERCOT area, was the third coldest on record on Feb. 15, just behind Feb. 12, 1899, and Dec. 23, 1989. The coldest nonoverlapping seven-day period of the cold wave was in a virtual tie with three other historical periods for second place, with a week in December 1983 outdoing all of them.

        On the whole, according to Nielsen-Gammon, extreme cold in Texas is getting less rather than more common.

        “No matter how they’re measured, cold-air outbreaks have decreased in frequency and severity in Texas and in most locations in the Northern Hemisphere midlatitudes,” Nielsen-Gammon said.

        Across Texas, he noted, the coldest readings in each winter month have been on the rise over the past several decades — in fact, rising twice as quickly as the average winter temperature.

        Blackport and Screen found much the same for midlatitude winters across the Northern Hemisphere. In a letter published last December in Nature Climate Change, they found that as a group, the coldest readings per winter at each point were rising at a more rapid pace than average winter temperatures at each point.

        The lead players in this decade-long debate agree on one thing: The case isn’t fully settled. “A lot of progress has been made, but there’s still a lot of open questions,” Screen said.

        Francis and colleagues, including Vavrus and Judah Cohen, who directs seasonal forecasting at Atmospheric and Environmental Research, are now working on a paper that will employ self-organizing maps, an increasingly popular tool for teasing out relationships that might otherwise go unanalyzed.

        Jet stream patterns in mid-July gave rise to intense zones of high pressure or “heat domes” (deep orange shade) that spread around the Northern Hemisphere midlatitudes. (WeatherBell)

        Meanwhile, research by Michael Mann at Pennsylvania State University and colleagues suggests that the “stuckness” of some recent summertime patterns, often leading to prolonged heat waves or flooding, may be related to resonant jet stream modes induced by global warming that lead to long-lasting, nearly stationary upper lows and highs. The last generation of global climate models couldn’t capture this resonance, Mann and colleagues found.

        A quick-response study coordinated by the World Weather Attribution group concluded that the Pacific Northwest heat wave of late June would have been “virtually impossible without human-caused climate change.” Although the report did not analyze the jet stream hypothesis directly, it said that nonlinear interactions not captured by climate models might have boosted the odds of an event this extreme. The other possibility, they said, is that the heat wave was an exceedingly low-probability event made more probable by overall rising temperatures — “the statistical equivalent of really bad luck, albeit aggravated by climate change.”

        Because there are different physics at work in the climate extremes of summer vs. winter, Mann isn’t sure if the same kind of modeling issues might be playing out with winter events, “but my gut instinct is that they may well be.”

        Overall, Mann said in an email, “I think the jury is still very much out. And I applaud both ‘camps’ for continuing to examine the best available data and models to get to the bottom of this. Eventually, this work will converge toward a scientific consensus. It’s not easy, but it’s how the gears of science turn, and it’s how we move forward toward a better physical understanding of the world.”


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