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Post by swamprat on Dec 28, 2019 21:26:22 GMT
Satellites Show Glaciers Rapidly Shrinking from Climate Change By Elizabeth Howell | Dec. 28, 2019
The Earth's glaciers are in rapid retreat.
New results relying on five decades of satellite observations show extensive changes to glaciers at the Earth's north and south poles, a result of global warming.
Much of the data comes courtesy of the long-running Landsat mission, which is a series of Earth observation satellites managed by NASA and the United States Geological Survey. Having decades of data from a single line of similar satellites makes it much easier to see change over time. But other satellites are spotting changes as well, sometimes on timescales as short as a year or two.
Meltwater pools on the surface of Petermann Glacier in Greenland as seen by Landsat in June 2019. (Image credit: NASA/USGS)
Landsat images of glaciers photographed between 1972 and 2019 allowed glaciologist Mark Fahnestock of the University of Alaska, Fairbanks, to create six-second time-lapse films showing changes in the ice.
"We now have this long, detailed record that allows us to look at what's happened in Alaska," Fahnestock said in a NASA statement. "When you play these movies, you get a sense of how dynamic these systems are and how unsteady the ice flow is."
Glaciers respond to global warming in different ways. For example, Alaska's Columbia glacier was pretty stable when the first Landsat satellite peered at it in 1972. It began a quick retreat in the mid-1980s; it now is 12.4 miles (20 kilometers) upstream from its first observed position nearly 48 years ago. Meanwhile, the nearby Hubbard Glacier has only moved three miles (five km) in the same 48 years, but a 2019 image showed a large area in the glacier where ice broke off. That "calving embayment," as geologists term it, is likely a sign of rapid change on the horizon.
"That calving embayment is the first sign of weakness from Hubbard glacier in almost 50 years — it's been advancing through the historical record," Fahnestock said, warning that the Columbia glacier showed similar signs of weakening before its rapid retreat decades ago.
Michalea King, a doctoral student in earth sciences at Ohio State University, examined similar Landsat images from Greenland as far back as 1985 to see how global warming affected 200 glaciers there. These glaciers have retreated an average of three miles (five km) over the period of satellite observations that King studied.
"These glaciers are calving more ice into the ocean than they were in the past," King said in the same statement. "There is a very clear relationship between the retreat, and increasing ice mass losses from these glaciers, during the 1985-through-present record."
The glacial retreat is also causing different sorts of lakes to appear over time on the surface of the glacier and underground. James Lea, a glaciologist at the University of Liverpool in the United Kingdom, found surface meltwater lakes on Greenland glaciers of up to three miles (five km) across. Lea used measurements gathered by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the NASA-led Terra satellite for every day of every melt season over the last 20 years.
"We looked at how many lakes there are per year across the ice sheet and found an increasing trend over the last 20 years: a 27% increase in lakes," Lea said in the same statement. "We're also getting more and more lakes at higher elevations — areas that we weren't expecting to see lakes in until 2050 or 2060."
The change is so rapid that sometimes differences show up in just a year or two. For example, Devon Dunmire of the University of Colorado, Boulder, used microwave radar images from the European Space Agency's Sentinel-1 satellite to peer beneath the ice. Dunmire spotted lakes in the George VI and Wilkins ice shelves near the Antarctica peninsula, including a few that remained liquid during winter.
"Not much is known about distribution and quantity of these subsurface lakes, but this water appears to be prevalent on the ice shelf near the Antarctic peninsula," said Dunmire, who is a graduate student in atmospheric and oceanic sciences, in the same statement. "It's an important component to understand, because meltwater has been shown to destabilize ice shelves."
The scientists presented their work at the annual meeting of the American Geophysical Union in San Francisco on Dec. 9.
www.space.com/satellites-show-rapidly-shrinking-glaciers.html
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Post by Deleted on Dec 30, 2019 17:42:12 GMT
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Post by Deleted on Dec 30, 2019 18:16:25 GMT
I’ve pretty much given up posting to this topic. The most discouraging thing to me is that while there may be some type of climate change, politicians have woven this into their political conversation fabric and actually think they can garner votes. Very simply, (those of you from SNL remember, but it was a metaphor to express some of the simplest concepts that even the, most intellectually challenged could still understand; as the round key goes in the trunk the square key goes in the ignition) back then keys were important for automotive control. Nothing humans can do can affect climate change. So, if some political candidate wants you to vote for him because he thinks you will vote for him because he’s gonna do something about climate change (and save the world just as Nemo did in 20,000 leagues under the Sea) you are sadly sucked in and mistaken. I repeat there is nothing humans can do about climate change. Unfortunately grants in college are awarded to those who side with of the deep state. If I were a college professor seeking funding, I would say anything to get funding and if that means siding with the deep state so what. At least now I still have a job at Harvard or Yale or Duke and I can support my kids even though nothing I say politically has any merit, I can still continue with my research, on how stem cells will cure cancer. But I tell everybody I’m really investigating climate change.
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Post by buzzbomb on Dec 31, 2019 3:45:00 GMT
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Post by HAL on Jan 1, 2020 21:30:19 GMT
Gort,
... If I were a college professor seeking funding, I would say anything to get funding ..
So college professors and politicians have at least one trait in common.
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Post by swamprat on Jan 24, 2020 20:56:21 GMT
The race to decipher how climate change influenced Australia’s record fires Researchers have started an attribution study to determine how much global warming is to blame for the blazes that have ravaged the continent.
Nicky Phillips & Bianca Nogrady | 23v January 2020
The Dunn’s Road fire burns pine trees near Maragle, New South Wales, on 10 January. Credit: Matthew Abbott/New York Times/Redux/eyevine
On 1 January, the air in Canberra was the worst of any city in the world. With unprecedented bush fires raging nearby, a thick blanket of smoke smothered Australia’s capital for weeks, sending a surge of residents to the hospital with breathing problems. The toxic haze got so bad that Sophie Lewis, a climate scientist at the University of New South Wales (UNSW) Canberra, took her toddler and boarded a plane to Tasmania.
“I almost wept with relief in Melbourne, on the way to Hobart, simply from seeing the sky,” she says. After weeks in the smoke, her daughter had grown used to all the people walking around with “bird beaks”, Lewis’s name for the masks everyone was wearing.
From Hobart, Lewis fielded e-mails from concerned colleagues overseas. Like the rest of the world, they were stunned by the scale and severity of the fires ravaging Australia (see ‘A country aflame’). Since September, more than 10 million hectares have burnt — an area greater than the size of Austria — and the fire season doesn’t end for several months in some states. So far, the conflagrations have killed at least 32 people and destroyed more than 2,000 homes across 3 states. Through it all, people have been asking Lewis: did climate change have a role in these catastrophic fires?
Lewis and a handful of her collaborators were busy discussing that very question. They work in a small but growing field called attribution science, which calculates the likelihood that an extreme event such as a heatwave, a flood or a catastrophic bush-fire season was made worse by climate change. In a study published last December, Lewis and her colleagues linked catastrophic 2018 fires in northeastern Australia to climate change, and they are now planning an attribution study for the fires that have gripped large parts of the country over the past few months (see ‘A country aflame’).
Sources: MODIS fire data: NASA; FIRMS/forest data: ESA
The work is being led by researchers in Europe who have conducted multiple rapid analyses of global warming’s role in extreme events. The team first has to grapple with how it will define the fire event for the purpose of its study: it is tricky to model the various weather conditions that increase fire risk, and the blazes haven’t yet died out. But once that is decided, the team could produce results as early as February.
Coming up with answers will be difficult. “Fire is probably the most complex physical and societal system known,” says Tim Brown, a climatologist at the Desert Research Institute in Reno, Nevada. “There’re so many different aspects of it, from the fuels and the people to the management practices.”
But Australia and other countries need to know what they are facing. If attribution studies can quantify the role of climate change in particular extreme events, scientists can better forecast the chances that the catastrophes will strike again. Such information is vital for emergency-response managers as they prepare for a warmer Earth. Firefighters in many countries have noticed, for instance, that big blazes are getting hotter and more dangerous, so modelling studies of future risks would help them train for and respond to the conflagrations to come.
Burning lands
Australia has always had fires — catastrophic ones, too. The really devastating ones earn their own name, such as Black Friday in 1939, Ash Wednesday in 1983 and Black Saturday in 2009. The last of those killed 173 people: the continent’s deadliest fire on record. All three — as well as the current crisis — happened amid or at the end of long, intense droughts.
This year’s unusually hot and dry conditions are driven in part by a natural meteorological phenomenon called the Indian Ocean Dipole (IOD), which is defined by differences in sea surface temperatures across the ocean. In its positive phase, warmer waters congregate near Africa, and rainfall is reduced over the southern and most northerly regions of Australia. This year saw one of the strongest positive swings in the IOD in recent history. Coupled with these events was a shift in the polar winds above Antarctica — also a natural phenomenon, but much rarer than a positive IOD. This sudden stratospheric warming, as it is known, contributed to bringing hot, dry weather to much of Australia. On top of all this natural variation, global warming is making the country even hotter and drier, says Sarah Perkins-Kirkpatrick, a climate scientist at UNSW Sydney.
Evidence has been growing for decades that climate change will exacerbate Australia’s fire seasons. A prescient paragraph in a 2008 government-commissioned climate report that compiled evidence from the previous 30 years warned that fire seasons would start earlier, end later and be more intense. “This effect increases over time, but should be directly observable by 2020,” noted the report, authored by Ross Garnaut, an economist at the University of Melbourne.
Lewis says we don’t need attribution studies to say that climate change is generally making fires in Australia worse. But as extreme events become more frequent — and the pace of warming shows no signs of falling — people want to know whether climate change had a hand in a specific extreme event.
Lewis’s study on the 2018 event looked at 130 bush fires that razed nearly 750,000 hectares over 5 days. On one climate model, the researchers ran thousands of simulations of future conditions, and they compared a world with current greenhouse-gas concentrations against one with pre-industrial levels. Those runs suggest that climate change had made the extreme temperatures — a major driver of fire weather — 4.5 times more likely. A second model showed that the below-average rainfall was also linked to increased greenhouse-gas concentrations, but only in some climate scenarios. The researchers say the study is one of many that connect climate change to increasing fire risks in eastern Australia. The work helps to confirm what many suspect about the impacts of the major warming in Australia, says Perkins-Kirkpatrick, one of the authors of the report. Nine of Australia’s ten hottest years on record have occurred in the past 15 years.
Cause and effect
Friederike Otto, a climate modeller at the University of Oxford, UK, started contemplating an attribution study on the Australian fires after she saw satellite images peppered with conflagrations and smoke plumes stretching across the continent. The event was too big to ignore, says Otto, who is a co-investigator at World Weather Attribution (WWA), a partnership led by the university’s Environmental Change Institute and the Royal Netherlands Meteorological Institute that analyses the effects of climate change on extreme weather. WWA decided to do a rapid attribution study, and invited Lewis, Perkins-Kirkpatrick and other researchers in Australia to join.
The first step in any attribution study is to set out the limits of the event, which is tricky in the Australian case because of the size of the area that has burnt and the time span over which it happened, says Perkins-Kirkpatrick. Once that has been done, the team will analyse whether temperature, rainfall and a ‘fire-weather’ index (FWI) — which includes those two variables and others — during the event were outside normal ranges. Last year was the country’s driest and hottest on record, and a heatwave that affected most of the country in December smashed the record for the hottest day ever recorded in Australia. The average maximum temperature across the country reached 41.9 °C on 18 December.
To see whether climate change had a role in these extremes, the group will use half a dozen climate models to run thousands of simulations, some reflecting current greenhouse-gas concentrations and others using pre-industrial levels. The group will also determine whether climate change made fire weather worse during the event.
Perkins-Kirkpatrick is confident the study will pinpoint the influence of climate change on extreme temperatures, but its effects on dryness, humidity and winds are much harder to assess. That’s why it’s important to analyse the extent to which global warming influenced both the FWI and the individual components, says Otto.
The team plans to publish its results in an open-review journal, as soon as they’re ready, and probably in the next couple of weeks. “For an event like this, where a lot of people have a lot of opinions on the role of climate change, it is important to make the scientific process as transparent as possible,” says Otto.
The study could also feed into future attribution work on fires, for which there has been a shortage of work. Hundreds of attribution studies have shown that climate change increased the risks of specific heatwaves — including a record one in Europe last year. But only a small fraction have looked at extreme fires, partly because fires are much more complex than heatwaves or droughts, says Brown. A report examining major fires in British Columbia in Canada in 2017 found that climate change made extreme fire weather two to four times more likely and increased the area of the province that burnt by at least a factor of seven. And a couple of studies have explored the factors driving a fivefold increase in the area burnt in California since the 1970s, and a twofold increase in burnt area in the western United States since the mid-1980s. Both studies found that the particular trend was probably driven by increased drying of leaves, twigs, tree branches and other ‘fuels’ as a result of global warming.
Incendiary behaviour
Most fire-attribution studies have focused on answering relatively straightforward questions, such as how much climate change contributed to, or exacerbated, the event. But Brown, whose team specializes in studying fire, wants to look deeper, and investigate how climate change is altering the behaviour of fires. In particular, he and his colleagues are looking at night-time warming, a factor he thinks might link global warming to bush-fire risk. When temperatures drop sharply at night, humidity tends to increase and that can help firefighters to suppress blazes. But when overnight temperatures remain high, fire managers have less success in combating fires, he says. Night-time temperatures have been climbing around much of the globe, and Brown is exploring whether that change is raising the risk of fires.
Scientists are also interested in examining whether fires are getting more severe. The increased fuel aridity makes fires burn hotter, which increases the chances that a blaze will create its own weather system, sparking lightning and throwing embers kilometres ahead of the fire front.
Smoke from these events can be so thick that it turns the sky an eerie red, or plunges everything into darkness. The haze travels for hundreds of kilometres, and can be seen from space. Lewis worries there isn’t enough attention on the health impacts for the millions of Australians who’ve endured months of thick smoke. Beyond the damage to people’s lungs, the fires can take a psychological toll. When residents are stuck indoors for weeks, Lewis says, the smoke “makes you feel stressed and anxious and on edge. Everything smells of smoke.”
Lewis and her family stayed in Tasmania for almost two weeks. Now back in Canberra, she’s seeing the effects this wild summer has had on her toddler, who has started asking where the red Sun went and what happened to all the bird-beak masks.
www.nature.com/articles/d41586-020-00173-7
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Post by nyx on Feb 4, 2020 23:03:14 GMT
The EU proclaimed that 2019 was the 2nd hottest year, and January 2020 was the hottest January ever.
Is this our future for the rest of 2020?
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Post by SysConfig on Feb 4, 2020 23:50:26 GMT
IMO If you brung all human activity to Zero..you would still have warming..It's always been the Sun ..all the chemical dumping to screen the rays, all the taxes from carbon credit scams will not stop it..the fact is..Earth as we know it..has a fever..and its dying..at some point..we'll be gone before it turns to a dry mud ball or a ball of ice.
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Post by swamprat on Feb 6, 2020 1:27:19 GMT
Arctic sinkholes open in a flash after permafrost melt By Mindy Weisberger - Senior Writer | 5 February 2020
Some permafrost zones thaw faster than expected and are reshaping the Arctic landscape.
Arctic permafrost can thaw so quickly that it triggers landslides, drowns forests and opens gaping sinkholes. This rapid melt, described in a new study, can dramatically reshape the Arctic landscape in just a few months.
Fast-melting permafrost is also more widespread than once thought. About 20% of the Arctic's permafrost — a blend of frozen sand, soil and rocks — also has a high volume of ground ice, making it vulnerable to rapid thawing. When the ice that binds the rocky material melts away, it leaves behind a marshy, eroded land surface known as thermokarst.
Previous climate models overlooked this kind of surface in estimating Arctic permafrost loss, researchers reported. That oversight likely skewed predictions of how much sequestered carbon could be released by melting permafrost, and new estimates suggest that permafrost could pump twice as much carbon into the atmosphere as scientists formerly estimated, the study found.
Frozen water takes up more space than liquid water, so when ice-rich permafrost thaws rapidly — "due to climate change or wildfire or other disturbance" — it transforms a formerly frozen Arctic ecosystem into a flooded, "soupy mess," prone to floods and soil collapse, said lead study author Merritt Turetsky, director of the Institute of Arctic and Alpine Research (INSTAAR) at the University of Colorado Boulder.
"This can happen very quickly, causing relatively dry and solid ecosystems (such as forests) to turn into lakes in the matter of months to years," and the effects can extend into the soil to a depth of several meters, Turetsky told Live Science in an email.
By comparison, "gradual thaw slowly affects soil by centimeters over decades," Turetsky said.
Creating feedback
Across the Arctic, long-frozen permafrost is melting as climate change drives global temperatures higher. Permafrost represents about 15% of Earth's soil, but it holds about 60% of the planet's soil-stored carbon: approximately 1.5 trillion tons (1.4 trillion metric tons) of carbon, according to the National Snow and Ice Data Center.
When permafrost thaws, it releases stored carbon into the atmosphere. This release can then speed up global warming; this cycle is known as climate feedback, the scientists wrote in the study.
Aerial image of a permafrost peatland in Alaska's Innoko National Wildlife Refuge, interspersed with smaller areas of thermokarst wetlands. (Image credit: Miriam Jones, U.S. Geological Survey)
In fact, carbon emissions from about 965,000 square miles (2.5 million square kilometers) of quick-thawed thermokarst could provide climate feedback similar to emissions produced by nearly 7 million square miles (18 million square km) of permafrost that thawed gradually, the researchers reported.
And yet, rapid thawing from permafrost is "not represented in any existing global model," study co-author David Lawrence, a senior scientist with the National Center for Atmospheric Research, said in a statement.
Abrupt permafrost thaw was likely excluded from prior emissions models because it represents such a small percentage of the Arctic's land surface, Turetsky explained.
"Our study proves that models need to account for both types of permafrost thaw — both slow and steady change as well as abrupt thermokarst — if the goal is to quantify climate feedbacks in the Arctic," Turetsky added.
The findings were published online Feb. 3 in the journal "Nature Geoscience".
www.livescience.com/arctic-permafrost-rapid-thaw.html
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Post by swamprat on Feb 7, 2020 20:21:51 GMT
Antarctica logs hottest temperature on record with a reading of 18.3C A new record set so soon after the previous record of 17.5C in March 2015 is a sign warming in Antarctica is happening much faster than global average
Graham Readfearn | 7 February 2020
The Argentinian Esperanza base in Antarctica – seen in March 2014 – recorded its hottest day on record on Thursday. Photograph: Vanderlei Almeida/AFP via Getty Images
Antarctica has logged its hottest temperature on record, with an Argentinian research station thermometer reading 18.3C, beating the previous record by 0.8C.
The reading, taken at Esperanza on the northern tip of the continent’s peninsula, beats Antarctica’s previous record of 17.5C, set in March 2015.
A tweet from Argentina’s meteorological agency on Friday revealed the record. The station’s data goes back to 1961.
Antarctica’s peninsula – the area that points towards South America – is one of the fastest warming places on earth, heating by almost 3C over the past 50 years, according to the World Meteorological Organization. Almost all the region’s glaciers are melting.
The Esperanza reading breaks the record for the Antarctic continent. The record for the Antarctic region – that is, everywhere south of 60 degrees latitude – is 19.8C, taken on Signy Island in January 1982.
Prof James Renwick, a climate scientist at Victoria University of Wellington, was a member of an ad-hoc World Meteorological Organization committee that has verified previous records in Antarctica.
He told Guardian Australia it was likely the committee would be reconvened to check the new Esperanza record.
He said: “Of course the record does need to be checked, but pending those checks, it’s a perfectly valid record and that [temperature] station is well maintained.”
“The reading is impressive as it’s only five years since the previous record was set and this is almost one degree centigrade higher. It’s a sign of the warming that has been happening there that’s much faster than the global average.
“To have a new record set that quickly is surprising but who knows how long that will last? Possibly not that long at all.”
He said the temperature record at Esperanza was one of the longest-running on the whole continent.
Renwick said higher temperatures in the region tended to coincide with strong northwesterly winds moving down mountain slopes – a feature of the weather patterns around Esperanza in recent days.
He said there were complex weather patterns in the area, but the Esperanza reading was likely a combination of natural variability and background warming caused by rising levels of greenhouse gases in the atmosphere.
He said: “The reason the peninsula is warming faster than other places is a combination of natural variations and warming signals.”
Prof Nerilie Abram, a climate scientist at the Australian National University, has carried out research at James Ross Island at the northern tip of the peninsula.
“It’s an area that’s warming very quickly,” she said, adding it can occasionally be warm enough to wear a T-shirt.
Previous research from 2012 found the current rate of warming in the region was almost unprecedented over the past 2000 years.
Abram said: “Even small increases in warming can lead to large increases in the energy you have for melting the ice. The consequences are the collapse of the ice shelves along the peninsula.”
Meltwater can work its way through cracks in ice shelves, she said. Because ice shelves already float on the ocean, their collapse does not directly contribute to rising sea levels.
But Abram said the shelves acted as plugs, helping to keep the ice sheets behind them stable. Melting of ice sheets does contribute to rising sea levels because they are attached to land.
Dr Steve Rintoul, a leading oceanographer and Antarctic expert at CSIRO, said: “This is a record from only a single station, but it is in the context of what’s happening elsewhere and is more evidence that as the planet warms we get more warm records and fewer cold records.”
The lowest temperature ever recorded in Antarctica – and anywhere on Earth – was at the Russian Vostok station, when temperatures dropped to -89.2C on 21 July 1983.
www.theguardian.com/world/2020/feb/07/antarctica-logs-hottest-temperature-on-record-with-a-reading-of-183c
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Post by Deleted on Feb 14, 2020 16:05:56 GMT
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Post by Deleted on Feb 14, 2020 16:30:34 GMT
At one time the Earth was a solid ice cube, and we have had several ice ages without human intervention, now I would call that climate change.
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Post by Deleted on Feb 14, 2020 17:16:54 GMT
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Post by Deleted on Feb 14, 2020 17:48:45 GMT
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Post by HAL on Feb 14, 2020 19:21:15 GMT
Gort,
If the earth is made up of water, rock and minerals, how can it ever have been a solid block of ice ?
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