Methane Releases from Arctic Shelf May Be Much Larger and Faster Than Anticipated
A section of the Arctic Ocean seafloor that holds vast stores of frozen methane is showing signs of instability and widespread venting of the powerful greenhouse gas, according to the findings of an international research team led by University of Alaska Fairbanks scientists Natalia Shakhova and Igor Semiletov.
The research results, published in the March 5 edition of the journal Science, show that the permafrost under the East Siberian Arctic Shelf, long thought to be an impermeable barrier sealing in methane, is perforated and is starting to leak large amounts of methane into the atmosphere. Release of even a fraction of the methane stored in the shelf could trigger abrupt climate warming.
“The amount of methane currently coming out of the East Siberian Arctic Shelf is comparable to the amount coming out of the entire world’s oceans,” said Shakhova, a researcher at UAF’s International Arctic Research Center. “Subsea permafrost is losing its ability to be an impermeable cap.”
Methane is a greenhouse gas more than 30 times more potent than carbon dioxide. It is released from previously frozen soils in two ways. When the organic material (which contains carbon) stored in permafrost thaws, it begins to decompose and, under anaerobic conditions, gradually releases methane. Methane can also be stored in the seabed as methane gas or methane hydrates and then released as subsea permafrost thaws. These releases can be larger and more abrupt than those that result from decomposition. (more…)
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Ice Shelves Disappearing on Antarctic Peninsula
This image shows ice-front retreat in part of the southern Antarctic Peninsula from 1947 to 2009. USGS scientists are studying coastal and glacier change along the entire Antarctic coastline. The southern portion of the Antarctic Peninsula is one area studied as part of this project. (U.S. Geological Survey)
Ice shelves are retreating in the southern section of the Antarctic Peninsula due to climate change. This could result in glacier retreat and sea-level rise if warming continues, threatening coastal communities and low-lying islands worldwide.
Research by the U.S. Geological Survey is the first to document that every ice front in the southern part of the Antarctic Peninsula has been retreating overall from 1947 to 2009, with the most dramatic changes occurring since 1990. The USGS previously documented that the majority of ice fronts on the entire Peninsula have also retreated during the late 20th century and into the early 21st century.
The ice shelves are attached to the continent and already floating, holding in place the Antarctic ice sheet that covers about 98 percent of the Antarctic continent. As the ice shelves break off, it is easier for outlet glaciers and ice streams from the ice sheet to flow into the sea. The transition of that ice from land to the ocean is what raises sea level.
“This research is part of a larger ongoing USGS project that is for the first time studying the entire Antarctic coastline in detail, and this is important because the Antarctic ice sheet contains 91 percent of Earth’s glacier ice,” said USGS scientist Jane Ferrigno. “The loss of ice shelves is evidence of the effects of global warming. We need to be alert and continually understand and observe how our climate system is changing.” (more…)
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Team Finds Subtropical Waters Flushing Through Greenland Fjord
Fiamma Straneo from the physical oceanography department at Woods Hole Oceaonographic Institution, at work on the deck of the Arctic Sunrise. (© Greenpeace/ Nick Cobbing)
Waters from warmer latitudes — or subtropical waters — are reaching Greenland’s glaciers, driving melting and likely triggering an acceleration of ice loss, reports a team of researchers led by Fiamma Straneo, a physical oceanographer from the Woods Hole Oceanographic Institution (WHOI).
“This is the first time we’ve seen waters this warm in any of the fjords in Greenland,” says Straneo. “The subtropical waters are flowing through the fjord very quickly, so they can transport heat and drive melting at the end of the glacier.”
Greenland’s ice sheet, which is two-miles thick and covers an area about the size of Mexico, has lost mass at an accelerated rate over the last decade. The ice sheet’s contribution to sea level rise during that time frame doubled due to increased melting and, to a greater extent, the widespread acceleration of outlet glaciers around Greenland.
While melting due to warming air temperatures is a known event, scientists are just beginning to learn more about the ocean’s impact — in particular, the influence of currents — on the ice sheet.
“Among the mechanisms that we suspected might be triggering this acceleration are recent changes in ocean circulation in the North Atlantic, which are delivering larger amounts of subtropical waters to the high latitudes,” says Straneo. But a lack of observations and measurements from Greenland’s glaciers prior to the acceleration made it difficult to confirm. (more…)
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Measurement Flights in the Arctic Polar Vortex Will Help Predict Ozone Depletion
The research aircraft "M55 Geophysica" is one of three aircraft worldwide that can fly at altitudes of up to 21 kilometres. (Photo: Forschungszentrum Jülich)
An international measurement campaign began yesterday in the northern Swedish city of Kiruna. The campaign aims to clarify unanswered questions related to polar ozone depletion in the stratosphere. Measurement flights at altitudes of up to 20 kilometres will provide researchers with data for global climate models, which they will then use to make even more accurate predictions of the future development of the ozone layer and to determine the impact on climate.
The campaign, which will last several weeks, is part of the EU project “RECONCILE” involving 17 partners from nine countries. RECONCILE is coordinated by scientists from Forschungszentrum Jülich, member of the Helmholtz Association of German Research Centres.
“We know what processes deplete ozone in the stratosphere but we don’t know how fast these processes are. This is what we now want to measure with our partners,” says RECONCILE coordinator Marc von Hobe from Forschungszentrum Jülich. Every winter, what is known as the polar vortex forms in the Arctic.
In this vortex, the air in the stratosphere circulates around the pole and is thus isolated from air masses at lower latitudes. Extremely low temperatures in the polar vortex lead to the formation of polar stratospheric clouds. These in turn accelerate the formation of chlorine radicals, small molecules that deplete ozone, and in extreme cases, lead to the hole in the ozone layer. (more…)
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Ice Mission Satellite Arrives Safely at Launch Site
CryoSat-2 arrives safely at Baikonur launch site in Kazakhstan on 13 January. (ESA/W.Simpson)
In what might seem rather appropriate weather conditions, the CryoSat-2 Earth Explorer satellite has completed its journey to the Baikonur launch site in Kazakhstan, where it will be prepared for launch on 25 February.
The satellite and support equipment left the ‘IABG’ test centre in Ottobrunn, Germany, by lorry on 12 January. The CryoSat mission is dedicated to precise monitoring of the changes in the thickness of marine ice floating in the polar oceans and variations in the thickness of the vast ice sheets that overlay Greenland and Antarctica. With much of Europe still in the grip of one of the coldest winters for some years, the icy conditions aptly set the stage for this first leg of CryoSat-2’s journey.
After arriving at Munich airport, the containers were loaded onto an Antonov aircraft. Along with team members from ESA and their industrial partner for CryoSat-2, EADS-Astrium, the Antonov took off in the early evening bound for Ulyanovsk, a city some 900 km east of Moscow, Russia. Once through customs clearance at Ulyanovsk, the aircraft continued the journey to the Baikonur Cosmodrome.
The weather was –12°C and fine on arrival. Safely cocooned in its thermally controlled container, CryoSat-2 and accompanying cargo were offloaded and moved to the integration facility. The launch campaign team will now spend the next six weeks preparing the satellite for launch. CryoSat-2 will be launched by a Dnepr rocket – a converted intercontinental ballistic missile – on 25 February at 14:57 CET (13:57 UT). (more…)
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Melting Tundra Creating Vast River of Waste into Arctic Ocean
By Krister Svahn
The increase in temperature in the Arctic has already caused the sea-ice there to melt. According to research conducted by the University of Gothenburg, if the Arctic tundra also melts, vast amounts of organic material will be carried by the rivers straight into the Arctic Ocean, resulting in additional emissions of carbon dioxide.
Several Russian rivers enter the Arctic Ocean particularly in the Laptev Sea north of Siberia. One of the main rivers flowing into the Laptev Sea is the Lena, which in terms of its drainage basin and length is one of the ten largest rivers in the world. The river water carries organic carbon from the tundra, and research from the University of Gothenburg shows that this adds a considerable amount of carbon dioxide to the atmosphere when it is degraded in the coastal waters.
Increased temperatures
The increase in temperature in the Arctic, which has already made an impact in the form of reduced sea-ice cover during the summer, may also cause the permafrost to melt.
“Large amounts of organic carbon are currently stored within the permafrost and if this is released and gets carried by the rivers out into the coastal waters, then it will result in an increased release of carbon dioxide to the atmosphere,” says Sofia Hjalmarsson, native of Falkenberg and postgraduate student at the Department of Chemistry. (more…)
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Arctic Could Face Warmer and Ice-Free Conditions
There is increased evidence that the Arctic could face seasonally ice-free conditions and much warmer temperatures in the future.
Scientists documented evidence that the Arctic Ocean and Nordic Seas were too warm to support summer sea ice during the mid-Pliocene warm period (3.3 to 3 million years ago). This period is characterized by warm temperatures similar to those projected for the end of this century, and is used as an analog to understand future conditions.
The U.S. Geological Survey found that summer sea-surface temperatures in the Arctic were between 10 to 18°C (50 to 64°F) during the mid-Pliocene, while current temperatures are around or below 0°C (32°F).
Examining past climate conditions allows for a true understanding of how Earth’s climate system really functions. USGS research on the mid-Pliocene is the most comprehensive global reconstruction for any warm period. This will help refine climate models, which currently underestimate the rate of sea ice loss in the Arctic. (more…)
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New Research Vessel Will Bring Scientists to Alaska’s Icy Northern Waters
A artist's rendering of the ARRV. (Image by The Glosten Associates)
More than three decades ago, marine scientists in the United States first identified the need for a research vessel capable of bringing scientists to Alaska’s icy northern waters.
The University of Alaska Fairbanks has announced its intent to award a $123 million contract that will meet that need. The university has selected Marinette Marine Corporation of Marinette, Wis. to build the 254-foot Alaska Region Research Vessel. When complete, the vessel will be one of the most advanced university research vessels in the world and will be capable of breaking ice up to 2.5 feet thick. According to project leaders, the ARRV’s home port will be in Alaska, most likely at UAF’s Seward Marine Center.
“Ocean scientists need this ice-capable vessel now, more than ever before, to study the changes occurring in arctic waters,” says Denis Wiesenburg, a co-principal investigator on the project and the dean of the UAF School of Fisheries and Ocean Sciences. (more…)
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International Expedition Investigates Climate Change & Alternative Fuels in Arctic
NRL's Marine Biogeochemistry section organized and led an international research expedition aboard the USCG Polar Sea in the Beaufort Sea during Sept. 15-26, 2009. (US Coast Guard)
Scientists from the Marine Biogeochemistry and Geology and Geophysics sections of the Naval Research Laboratory (NRL) organized and led a team of university and government scientists on an Arctic expedition to initiate methane hydrate exploration in the Beaufort Sea and determine the spatial variation of sediment contribution to Arctic climate change.
Utilizing the U.S. Coast Guard Cutter Polar Sea as a research platform, three cross-shelf transects were surveyed and sampled off Alaska’s North Slope at Hammerhead, Thetis Island and Halkett representing three regions of the Alaskan shelf. The expedition integrated expertise in coastal geophysics, sediment geochemistry, dissolved and free methane fluxes through the water column and into the atmosphere, sediment and water column microbiology and biogeochemistry and detailed characterization of the sub-seafloor geology.
“The objective of the sampling is to help determine variations in the shallow sediment and water column methane sources, methane cycling and the subsequent flux to the atmosphere,” said Richard Coffin, chief scientist, NRL Chemistry Division. (more…)
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Tackling New Arctic Challenges from Space
International scientists, researchers and decision makers met at the ‘Space and the Arctic workshop’ to identify the needs and challenges of working and living in the rapidly changing Arctic and to explore how space-based services can help to meet those needs.
The workshop, held from 20 to 21 October in Stockholm, Sweden, was organised by the Swedish National Space Board and the Swedish Meteorological and Hydrological Institute together with ESA, EUMETSAT and the EC.
The warmer climate, advances in technology and demand for natural resources are leading to increased human activity in the Arctic. This increase in activity, especially related to oil and gas production, changing fishery patterns and new shipping routes, provides new opportunities but also creates new risks to those working and living in the area and to the pristine and unique natural environment.
One of the highlights of the workshop was the ‘Arctic Marine Transport and Space’ presentation given by Dr Lawson Brigham of the University of Alaska Fairbanks that outlined the Arctic Marine Shipping Assessment (AMSA) report for 2009. (more…)
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Arctic Sediments Show That 20th Century Warming Is Unlike Natural Variation
Since the mid-20th century, changes seen in Arctic sediments retrieved by UB geologist Jason Briner and his colleagues, are unprecedented in the last 200,000 years.
Changes since the middle of the 20th century are unprecedented.
The possibility that climate change might simply be a natural variation like others that have occurred throughout geologic time is dimming, according to evidence in a Proceedings of the National Academy of Sciences paper published today.
The research reveals that sediments retrieved by University at Buffalo (UB) geologists from a remote Arctic lake are unlike those seen during previous warming episodes.
The UB researchers and their international colleagues were able to pinpoint that dramatic changes began occurring in unprecedented ways after the midpoint of the twentieth century.
“The sediments from the mid-20th century were not all that different from previous warming intervals,” said Jason P. Briner, PhD, assistant professor of geology in the UB College of Arts and Sciences. “But after that things really changed. And the change is unprecedented.” (more…)
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Arctic Lake Sediment Shows Warming, Unique Ecological Changes in Recent Decades
A University of Colorado at Boulder-led analysis of a 200,000 year-old sediment core from a Baffin Island lake indicates warming temperatures in the Arctic due to human activity are overriding a natural cooling trend in the region. (Photo by Jason Briner, University at Buffalo)
An analysis of sediment cores indicates that biological and chemical changes occurring at a remote Arctic lake are unprecedented over the past 200,000 years and likely are the result of human-caused climate change, according to a new study led by the University of Colorado at Boulder.
While environmental changes at the lake over the past millennia have been shown to be tightly linked with natural causes of climate change — like periodic, well-understood wobbles in Earth’s orbit — changes seen in the sediment cores since about 1950 indicate expected climate cooling is being overridden by human activity like greenhouse gas emissions. The research team reconstructed past climate and environmental changes at the lake on Baffin Island using indicators that included algae, fossil insects and geochemistry preserved in sediment cores that extend back 200,000 years. (more…)
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Arctic Has Potential to Alter Earth’s Climate As Source of Carbon Dioxide
Arctic land and seas account for up to 25 percent of world’s carbon sink.
This figure shows the mean extent of permafrost in the Arctic, estimated for (a) the years 1990-2000 and (b) the years 2090-2100. In (c), the estimation of loss of permafrost by 2100 is overlaid on estimations for the year 2000. (A. David McGuire)
In a new study in the journal Ecological Monographs, ecologists estimate that Arctic lands and oceans are responsible for up to 25 percent of the global net sink of atmospheric carbon dioxide. Under current predictions of global warming, this Arctic sink could be diminished or reversed, potentially accelerating predicted rates of climate change.
In their review paper, David McGuire of the U.S. Geological Survey and the University of Alaska at Fairbanks and his colleagues show that the Arctic has been a carbon sink since the end of the last Ice Age, which over time has accounted for between zero and 25 percent, or up to about 800 million metric tons, of the global carbon sink. On average, says McGuire, the Arctic accounts for 10-15 percent of the Earth’s carbon sink. But the rapid rate of climate change in the Arctic – about twice that of lower latitudes – could eliminate the sink and possibly make the Arctic a source of carbon dioxide. (more…)
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Arctic Sea Ice Extent Is Third Lowest on Record
Tom Wagner, NASA's cryosphere program manager, describes the shrinking of Arctic sea ice and the significance of the problem for the rest of the planet. (Jefferson Beck, NASA)
U.S. satellite measurements show Arctic sea ice extent in 2009 – the area of the Arctic Ocean covered by floating ice – was the third lowest since satellite measurements were first made in 1979. The ice area at minimum was an increase from the past two years, but still well below the average for the past 30 years.
Arctic sea ice reached its minimum extent around September 12, as shown in the image and video below/above. According to scientists affiliated with the National Snow and Ice Data Center (NSIDC), sea ice coverage dropped to 5.10 million square kilometers (1.97 million square miles) at its minimum. The ice cover was 970,000 square kilometers (370,000 square miles) greater than the record low of 2007 and 580,000 square kilometers (220,000 square miles) greater than 2008.
NSIDC is sponsored by several U.S. government agencies, including NASA. Ice data are derived from measurements made by U.S. Department of Defense and NASA satellites, with key work in interpreting the data and developing the 30-year history done by scientists at NASA’s Goddard Space Flight Center in Greenbelt, Md. (more…)
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Scientists Seek New Emphases in Arctic Climate Change Research
PhD student Ken Tape digging a pit to measure physical parameters of snow near an experimental snow fence at Toolik Field Station in November of 2006. (Photo: Greg Goldsmith)
Much of circumpolar Arctic research focuses on the physical, direct changes resulting from climate warming such as sea ice retreat and temperature increases. “What’s understudied is the living component of the Arctic and that includes humans,” said Syndonia “Donie” Bret-Harte, associate professor of biology at the University of Alaska Fairbanks and co-author of a paper to be published September 11, 2009 in the journal Science.
The paper reviews current knowledge on the ecological consequences of climate change on the circumpolar Arctic and issues a call for action in several areas of global climate change research. (more…)
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Arctic Warming Overtakes 2,000 Years of Natural Cooling
New research shows that the Arctic reversed a long-term cooling trend and began warming rapidly in recent decades. The blue line shows estimates of Arctic temperatures over the last 2,000 years, based on proxy records from lake sediments, ice cores and tree rings. The green line shows the long-term cooling trend. The red line shows the recent warming based on actual observations. A 2000-year transient climate simulation with NCAR’s Community Climate System Model shows the same overall temperature decrease as does the proxy temperature reconstruction, which gives scientists confidence that their estimates are accurate. (Courtesy Science, modified by UCAR.)
Arctic temperatures in the 1990s reached their warmest level of any decade in at least 2,000 years, new research indicates. The study, which incorporates geologic records and computer simulations, provides new evidence that the Arctic would be cooling if not for greenhouse gas emissions that are overpowering natural climate patterns.
The international study, led by Northern Arizona University and the National Center for Atmospheric Research (NCAR), will be published in the September 4 edition of Science. It was primarily funded by the National Science Foundation, NCAR’s sponsor.
The scientists reconstructed summer temperatures across the Arctic over the last 2,000 years by decade, extending a view of climate far beyond the 400 years of Arctic-wide records previously available at that level of detail. They found that thousands of years of gradual Arctic cooling, related to natural changes in Earth’s orbit, would continue today if not for emissions of carbon dioxide and other greenhouse gases. (more…)
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Satellites and Submarines Give the Skinny on Sea Ice Thickness
Changes to sea ice influence the Arctic's local weather, climate and ecosystems -- and also polar bears, seen here from an icebreaking ship that passed though the Northwest Passage this summer during an eight-day series of meetings to discuss Arctic science. (Ronald Kwok/NASA)
This summer, a group of scientists and students — as well as a Canadian senator, a writer, and a filmmaker — set out from Resolute Bay, Canada, on the icebreaker Louis S. St-Laurent. They were headed through the Northwest Passage, but instead of opening shipping lanes in the ice, they had gathered to open up new lines of thinking on Arctic science.
Among the participants in the shipboard workshop (hosted by Fisheries and Oceans Canada) was Ron Kwok of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. Kwok has long provided checkups on the health of Arctic sea ice — the frozen sea water floating within the Arctic Ocean basin. He also knows that some important clues about ice changes can’t be seen from a ship.
While satellites provide accurate and expansive coverage of ice in the Arctic Ocean, the records are relatively new. Satellites have only monitored sea ice extent since 1973. NASA’s Ice, Cloud, and land Elevation Satellite (ICESat) has been on the task since 2003, allowing researchers to estimate ice thickness as well.
To extend the record, Kwok and Drew Rothrock of the University of Washington, Seattle, recently combined the high spatial coverage from satellites with a longer record from Cold War submarines to piece together a history of ice thickness that spans close to 50 years. (more…)
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Climate Change May Impact Circulation of World’s Oceans
A seaglider is prepared for deployment in Davis Strait by Avery Snyder and Adam Huxtable, field engineers with the University of Washington's Applied Physics Laboratory. (Applied Physics Laboratory/U. of Washington)
The University of Washington has surpassed its 2-year-old world record for operating a glider under the ice, this time by successfully operating one of its seagliders for six months as it made round trips hundreds of miles in length under the ice at Davis Strait.
The result contributes to the longest continuous measurement of fresh water exiting the Arctic through the Canadian Arctic Archipelago and Davis Strait and into the Labrador Sea.
Scientists worry that climate change may increase the amount of fresh water so much that it impacts the formation of very dense water in the Labrador Sea. That dense, cold water is a critical component driving the circulation of the world’s oceans, according to Craig Lee, a principal oceanographer with the UW’s Applied Physics Laboratory. Lee and senior oceanographer Jason Gobat lead the group developing the under-ice seaglider. (more…)
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Aerosols May Drive a Significant Portion of Arctic Warming
By Adam Voiland
Aerosols can influence climate directly by either reflecting or absorbing the sun's radiation as it moves through the atmosphere. The tiny airborne particles enter the atmosphere from sources such as industrial pollution, volcanoes and residential cooking stoves. Credit: NASA Goddard's Scientific Visualization Studio
Though greenhouse gases are invariably at the center of discussions about global climate change, new NASA research suggests that much of the atmospheric warming observed in the Arctic since 1976 may be due to changes in tiny airborne particles called aerosols.
Emitted by natural and human sources, aerosols can directly influence climate by reflecting or absorbing the sun’s radiation. The small particles also affect climate indirectly by seeding clouds and changing cloud properties, such as reflectivity. (more…)
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Ice-Free Arctic Summers Likely Sooner Than Expected
Mean sea ice thickness in meters for March (left) and September (right) based on six models. Top panels: September ice extent reached the current level by these models. Bottom panels: Arctic reached nearly "ice-free summer" conditions. (Credit: University of Washington / NOAA)
Summers in the Arctic may be ice-free in as few as 30 years, not at the end of the century as previously expected. The updated forecast is the result of a new analysis of computer models coupled with the most recent summer ice measurements.
“The Arctic is changing faster than anticipated,” said James Overland, an oceanographer at NOAA’s Pacific Marine Environmental Laboratory and co-author of the study, which will appear April 3 in Geophysical Research Letters. “It’s a combination of natural variability, along with warmer air and sea conditions caused by increased greenhouse gases.”
Overland and his co-author, Muyin Wang, a University of Washington research scientist with the Joint Institute for the Study of the Atmosphere and Ocean in Seattle, analyzed projections from six computer models, including three with sophisticated sea ice physics capabilities. That data was then combined with observations of summer sea ice loss in 2007 and 2008. (more…)
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Polar Research Reveals New Evidence of Global Enviroinmental Change
Thousands of scientists, from more than 60 countries and a wide range of research disciplines, were involved in more than 160 projects. They have gained new understanding about the role of the polar regions in the Earth system. (© Christian Morel/WMO)
Multidisciplinary research from the International Polar Year (IPY) 2007-2008 provides new evidence of the widespread effects of global warming in the polar regions. Snow and ice are declining in both polar regions, affecting human livelihoods, local plant and animal life in the Arctic, as well as global ocean and atmospheric circulation and sea level. These are but a few findings reported in “State of Polar Research”, released today by the World Meteorological Organization (WMO) and the International Council for Science (ICSU). In addition to lending insight into climate change, IPY has aided our understanding of pollutant transport, species’ evolution, and storm formation, among many other areas.
The wide-ranging IPY findings result from more than 160 endorsed science projects assembled from researchers in more than 60 countries. Launched in March 2007, the IPY covers a two-year period to March 2009 to allow for observations during the alternate seasons in both polar regions. A joint project of WMO and ICSU, IPY spearheaded efforts to better monitor and understand the Arctic and Antarctic regions, with international funding support of about US$ 1.2 billion over the two-year period.
“The International Polar Year 2007 – 2008 came at a crossroads for the planet’s future” said Michel Jarraud, Secretary-General of WMO. “The new evidence resulting from polar research will strengthen the scientific basis on which we build future actions.”
Catherine Bréchignac, President of ICSU, adds “the planning for IPY set ambitious goals that have been achieved, and even exceeded, thanks to the tireless efforts, enthusiasm, and imagination of thousands of scientists, working with teachers, artists, and many other collaborators.” (more…)
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Sea Level Rise Could Be Worse Than Anticipated
COULD SEA LEVEL RISE TO THE STEPS OF THE U.S. CAPITOL?
If global warming some day causes the West Antarctic Ice Sheet to collapse, as many experts believe it could, the resulting sea level rise in much of the United States and other parts of the world would be significantly higher than is currently projected, a new study concludes.
The catastrophic increase in sea level, already projected to average between 16 and 17 feet around the world, would be almost 21 feet in such places as Washington, D.C., scientists say, putting it largely underwater. Many coastal areas would be devastated. Much of southern Florida would disappear. (more…)
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