Science & Environment

[CaaC (John)+]

Only ever seen them once in Aberdeen when I was working up that way around 2000, wish I could see them again they are spell-bounding, sigh   

 

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The Northern Lights may be visible from Scotland this weekend

Alex Nelson

Forecasters have said that the Northern Lights might be visible from the UK this weekend (23 March), thanks to a solar storm on its way to Earth.

Those at higher latitudes are more likely to catch a glimpse of the aurora borealis said the Met Office, particularly those in Scotland.

The Northern Lights are created by disturbances in Earth's magnetosphere caused by a flow of particles from the Sun and are usually concentrated around the Earth's magnetic poles.

They can spread further south when the concentration of particles is higher, for instance following a Coronal Mass Ejection (CME) of plasma from the sun.

One such Ejection occurred on Wednesday (20 March), following a solar flare.

What are my chances of actually seeing the Northern Lights?

The Met Office's Space account tweeted, "CME forecast to arrive late 23rd March following C5 flare from sunspot AR2736.”

Bonnie Diamond, meteorologist at the Met Office, said, "A Coronal Mass Ejection has happened and the effects of that are expected to arrive later tomorrow evening.

Watch: Northern Lights dance in Lapland sky (Sky News)

 

"Whether or not you will see the Northern Lights depends on where you are and what the weather is like."

The forecast for Glasgow and Edinburgh doesn’t bode well for those keen to see the lights, although cloud could break long enough to catch a glimpse.

Watch: Met Office explains the Northern Lights (Evening Standard)

The weather for more northern areas looks better, with the Scottish Highlands, Dundee and Aberdeen predicted to have clearer skies.

"The clearest skies are further east in Aberdeenshire, where there are plenty of clear skies. Further north, you're pretty likely to see something," said Diamond.

https://www.msn.com/en-gb/weather/topstories/the-northern-lights-may-be-visible-from-scotland-this-weekend/ar-BBV68nl?ocid=chromentp

 

 

 

[nudge]

2 minutes ago, CaaC - John said:

Only ever seen them once in Aberdeen when I was working up that way around 2000, wish I could see them again they are spell-bounding, sigh   

That's one thing on my bucket list... Would love to see that.

[CaaC (John)+]

'Mission Jurassic' dinosaur hunt to get underway

British scientists are about to undertake one of their biggest dinosaur hunts in decades.

They are joining the US and Dutch institutions in exploring what is expected to be a treasure trove of fossils in the "Badlands" of Wyoming.

The US state has yielded some of the most famous specimens ever found, and the international group will excavate one square mile (260ha) of the ground.

"It's an incredible site, mind-blowing," said Prof Phil Manning.

"In the UK, we rarely see anything like this - whole dinosaurs coming out of the ground. But that's what we've got here," the University of Manchester palaeontologist told BBC News.

"And the funding we have in place permits us to open up football pitch-sized areas at a time if need be."

The partners on the project are The Children's Museum of Indianapolis; the Naturalis Biodiversity Center in Leiden; and London's Natural History Museum.

Prof Manning and Manchester colleague Dr Victoria Egerton are Extraordinary Scientists in Residence at the Children's Museum and will act as lead researchers, but such is the scale of this endeavour that a team of more than 100 experts will be required.

The project has been dubbed "Mission Jurassic" - a reference to the major geological period in which the rocks to be studied were laid down.

In this particular part of North Wyoming, the scientists will get access to a unit, or formation, known as the Morrison.

"These were deposited from about 157 million to 145 million years ago," explained the NHM's, Dr Susannah Maidment.

"The formation has been extensively studied to the south, producing all of your favourite dinosaurs that you could name when you were seven - the likes of Stegosaurus, Brachiosaurus, Brontosaurus and Allosaurus. But we'll be in the north, which has been much less studied, and which it's suggested might hold slightly different creatures.

"So we're hoping to find animals that have never been seen before."

Already, there have been some exploratory investigations in the area.

This early work, carried out by Prof Manning and colleagues, has merely heightened the anticipation.

Several tonnes of bones were recovered, including fossils from two giant sauropod dinosaurs - a 24m-long Brachiosaurus and a 30m-long Diplodocus.

"We've got chicken-sized theropods as well," said Prof Manning, of the familiar bipedal dinosaurs out of which modern birds are descended. "I'm hoping if we can find more of this material, we might learn something about the evolution of flight."

The dig team will work through a range of ancient environments, including a river and floodplain setting; and another that appears to record a marine history.

"So, this is not just about dinosaurs," said the NHM's Prof Paul Barrett. "Obviously, they're the charismatic creatures, but we're also interested in everything that's living alongside the dinosaurs, to build up a complete picture of that ecosystem. Things like ancient crocodiles, lizards, turtles, fish, clams, plants - we'll be taking specialists with us so we can delve deeply into that picture."

Prof Barrett said Mission Jurassic was the largest expedition of its type for the NHM since a venture in Niger in the 1980s.

The institution - as the UK's premier fossil display centre - hopes many of the specimens that are discovered can be brought to London. Although the NHM has an extraordinary collection of fossils, it concedes that it's North American compilation could be stronger.

One excellent opportunity the project will afford is educational - both for UK PhD students, who will be able to work in the field; but also for the public. There are plans to live stream events around the digs so that people can get a first-hand insight of what it's like to discover fossils that are totally new to science.

https://www.bbc.co.uk/news/science-environment-47684989

 

[CaaC (John)+]

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Chicxulub asteroid impact: Stunning fossils record dinosaurs' demise

Scientists have found an extraordinary snapshot of the fallout from the asteroid impact that wiped out the dinosaurs 66 million years ago.

Excavations in North Dakota reveal fossils of fish and trees that were sprayed with rocky, glassy fragments that fell from the sky.

The deposits show evidence also of having been swamped with water - the consequence of the colossal sea surge that was generated by the impact.

The detail is reported in PNAS journal.

Robert DePalma, from the University of Kansas, and colleagues say the dig site, at a place called Tanis, gives an amazing glimpse into events that probably occurred perhaps only tens of minutes to a couple of hours after the giant asteroid hit the Earth.

When this 12km-wide object slammed into what is now the Gulf of Mexico, it would have hurled billions of tonnes of molten and vaporised rock into the sky in all directions - and across thousands of kilometres.

And at Tanis, the fossils record the moment this bead-sized material fell back down and strafed everything in its path.

Fish are found with the impact-induced debris embedded in their gills. They would have breathed in the fragments that filled the water around them.

There are also particles caught in amber, which is the preserved remnant of tree resin. It is even possible to discern the wake left by these tiny, glassy tektites, to use the technical term, as they entered the resin.

Geochemists have managed to link the fallout material directly to the so-called Chicxulub impact site in the Gulf. They have also dated the debris to 65.76 million years ago, which is in very good agreement with the timing for the event worked out from evidence at other sites around the world.

From the way the Tanis deposits are arranged, the scientists can see that the area was hit by a massive surge of water.

Although the impact is understood to have generated a huge tsunami, it would have taken many hours for this wave to travel the 3,000km from the Gulf to North Dakota, despite the likely presence back then of a seaway cutting directly across the American landmass.

Instead, the researchers believe local water could have been displaced much more quickly by the seismic shockwave - equivalent to a Magnitude 10 or 11 earthquake - that would have rippled around the Earth. It is a type of surge described as a seiche, which would have picked up everything in its path and dumped it into the jumbled collection of specimens now being reported by the team.

"A tangled mass of freshwater fish, terrestrial vertebrates, trees, branches, logs, marine ammonites and other marine creatures was all packed into this layer by the inland-directed surge," said Mr DePalma.

"A tsunami would have taken at least 17 or more hours to reach the site from the crater, but seismic waves - and a subsequent surge - would have reached it in tens of minutes," he added.

The PNAS paper, which will go online on Monday, includes among its authors Walter Alvarez, the Californian geologist who, with his father Luis Alvarez, is credited with helping to develop the impact theory for the demise of the dinosaurs.

The Alvarez pair identified a layer of sediment at the boundary of the Cretaceous and Palaeogene geological periods that was enriched with iridium, an element commonly found in asteroids and meteorites.

Iridium traces are also found to be capping the Tanis deposits.

"When we proposed the impact hypothesis to explain the great extinction, it was based just on finding an anomalous concentration of iridium - the fingerprint of an asteroid or comet," said Prof Alvarez. "Since then, the evidence has gradually built up. But it never crossed my mind that we would find a deathbed like this."

Phil Manning, from the University of Manchester, the only British author on the paper, commented: "It's one of the most important sites in the globe now. You know, if you truly wanted to understand the last day of the dinosaurs - this is it," he told BBC News.

https://www.bbc.co.uk/news/science-environment-47755275

 

 

[Azeem]

In Singapore a child's mom died giving birth. The heart of the mom was donated to a person . The child when was hold by that person gave reactions that looks like he recognized the heart beat of his mother

[CaaC (John)+]

1 hour ago, Azeem said:

In Singapore a child's mom died giving birth. The heart of the mom was donated to a person . The child when was hold by that person gave reactions that looks like he recognized the heart beat of his mother

Is this the one @Azeem?

 

44M views · 

about 6 months ago · 

When the baby's mother died during the birth, her parents donated her heart. Watch out for the guy in the black shirt. He's the one who took the heart!

[Azeem]

55 minutes ago, CaaC - John said:

Is this the one @Azeem?

 

44M views · 

about 6 months ago · 

When the baby's mother died during the birth, her parents donated her heart. Watch out for the guy in the black shirt. He's the one who took the heart!

Yep

[Azeem]

Heat map of CO2 emmision 

[CaaC (John)+]

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Sydney Brenner: Molecular biology pioneer dies

Sydney Brenner, one of the giants of 20th Century science, has died.

The Lithuanian-born South African made many pioneering discoveries in the field of molecular and developmental biology, winning a Nobel Prize in 2002.

The Nobel recognised his work with the tiny roundworm Caenorhabditis elegans, which is now widely used by researchers as a model to test the fundamentals of how all living organisms work.

But Brenner also made big contributions to the understanding of DNA.

He worked routinely with the other greats in this area, such as Francis Crick, François Jacob, Linus Pauling and James Watson.

• Listen: Sydney Brenner - A Revolutionary Biologist

Brenner helped establish the role played by the molecule RNA in carrying the "code of life" held in the DNA sequence to the ribosome protein factories in cells.

He also realised the significance of codons - the sets of three bases, or "letters" - in the DNA sequence that signify the correct string of amino acids the ribosomes should use to assemble the proteins.

It is the proteins - enzymes and hormones, etc - that ultimately construct and maintain our bodies.

Born in 1927, Sydney Brenner had an impoverished start to life as an immigrant in South Africa and famously taught himself to read from the newspapers that were used as tablecloths at dinner time.

But his precocious talent saw him win a scholarship to medical school at the age of just 15.

He later went on to study for a PhD at Oxford University in the UK, before moving across to Cambridge where he joined the hothouse environment of the Laboratory of Molecular Biology.

The LMB produced a stream of Nobel Prize winners, and he was its second director from 1979 to 1986.

In his later years, he put much effort into building scientific capacity in Singapore.

And it was the Agency for Science, Technology and Research (A*STAR), Singapore's lead public sector research agency, that announced Sydney Brenner's death on Friday morning.

https://www.bbc.co.uk/news/science-environment-47828986

 

 

 

Edited April 5, 2019 by CaaC - John

[Azeem]

Hunza, Pakistan becomes the first region in South Asia to ban plastic bags

[CaaC (John)+]

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UK's Sabre spaceplane engine tech in a new milestone

UK engineers developing a novel propulsion system say their technology has passed another key milestone.

The Sabre air-breathing rocket engine is designed to drive space planes to orbit and take airliners around the world in just a few hours.

To work, it needs to manage very high-temperature airflows, and the team at Reaction Engines Ltd has developed a heat-exchanger for the purpose.

This key element has just demonstrated an impressive level of performance.

It has shown the ability to handle the simulated conditions of flying at more than three times the speed of sound.

It did this by successfully quenching a 420C stream of gases in less than 1/20th of a second.

The REL group is confident its "pre-cooler" technology can now go on to show the same performance in conditions that simulate flying above five times the speed of sound, or Mach 5.

That would mean rapidly dumping the energy in a 1,000-degree airflow.

"We're now able to prove many of the claims we've been making as a business, backed up by very high-quality data," REL's CEO Mark Thomas told BBC News.

"In this most recent experiment, we've near-instantaneously transferred 1.5 Megawatts of heat energy - the equivalent of 1,000 homes' worth of heat energy."

The testing was conducted at a dedicated facility at the Colorado Air and Space Port in the US.

Sabre can be thought of as a cross between a jet engine and a rocket engine.

At slow speeds and at low altitude, it would behave like a jet, burning its fuel in a stream of air scooped from the atmosphere.

At high speeds and at high altitude, it would then transition to full rocket mode, combining the fuel with a small supply of oxygen the vehicle had carried aloft.

The early air-breathing approach would deliver substantial weight savings, and allow a space plane, for example, to go straight to orbit without throwing away propellant stages on the way up, as rockets do now.

But the concept brings with it an immense heat challenge.

The faster the flow of air into the engine's intake during the high-speed ascent, the higher the temperature.

And the heat would rise still further once the flow was slowed and compressed prior to entering the combustion chambers.

Such conditions would ordinarily melt the insides of the engine.

Sabre's pre-cooler seeks to solve this problem by efficiently, and swiftly, extracting the heat by first passing the intake gases through a tightly packed array of fine tubing. This tubing is fed with chilled helium.

In 2012, REL put the pre-cooler in front of a Viper jet engine and sucked ambient air through the heat exchanger. The gas stream immediately dropped to minus-150C.

Now, the company has flipped the set-up, putting the jet engine from an old F-4 Phantom fighter-bomber in front of the pre-cooler to drive hot gases directly across the piping array.

The completed Colorado experiment replicates the thermal conditions corresponding to flight at Mach 3.3, the record-breaking speed at which the American SR-71 Blackbird spy plane used to operate. Importantly, though, the pre-cooler took out all the heat.

"This technology has wide application, not just in the immediate, obvious domain of high-speed flight but across the aerospace industry more generally, and into more commercial applications - anywhere there's a significant heat-management challenge and you're looking for ultra-lightweight, miniaturised, high-performance solutions," Mr Thomas said.

The Colorado tests continue. Meanwhile, back in England, REL is progressing towards a demonstration of the core part of the engine, expected to get underway next year.

This core combustion section recently passed its preliminary design review under the eye of propulsion experts at the European Space Agency. Esa has been brought in by the UK government to act as a technical auditor on the project.

The Oxfordshire company is developing Sabre with the support of BAE Systems, Rolls-Royce and Boeing. All are keen to see the many years of refinement on the engine concept finally come to fruition.

https://www.bbc.co.uk/news/science-environment-47832920

 

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Edited April 8, 2019 by CaaC - John

[CaaC (John)+]

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Climate change: European team to drill for 'oldest ice' in Antarctica

An ambitious project to retrieve a continuous record of Earth's atmosphere and climate stretching back 1.5 million years is officially "go".

A European consortium will head to Antarctica in December to begin the process of drilling deep into the continent's eastern ice sheet.

The group's aim is to pull up a frozen core of material almost 3km long.

Scientists hope this can lead them to an explanation for why Earth's ice ages flipped in frequency in the deep past.

Although it might seem at first glance to be a rather esoteric quest, researchers say it bears down directly on the question of how much the world is likely to warm in the centuries ahead.

"Something happened about 900,000 years ago. The ice age cycles changed from every 40,000 years or so, to every 100,000 years; and we don't know why," Dr Catherine Ritz from the Institute of Environmental Geosciences in Grenoble, France, told BBC News.

"And it's rather important, because if we want to forecast what will happen to the climate in the future, with the increase in greenhouse gases, then we will have to use models, and these models will be calibrated on what happened in the past."

Dr Ritz was speaking here at the European Geosciences Union General Assembly, where the site for the new drilling operation was formally announced.

It will be on a high ridge about 40km southwest from the Franco-Italian research station known as Dome Concordia. Already, the spot has been dubbed "Little Dome C".

Fourteen institutions from 10 countries will participate in what's referred to as the Beyond-EPICA project.

It will probably take about five years to fully extract the core with at least a further year to examine the ice.

The expected total €30m (£26m) cost will be met out of the European Union's science budget, Horizon 2020.

How do ice cores record the climate of the past?

The ice in Antarctica is made up of snows that fell on the continent over millions of years.

As this ice was pressed down, it captured bubbles of air. These little gas pockets are a direct snapshot of the atmosphere.

Scientists can read off the levels of carbon dioxide and other heat-trapping components such as methane, for example.

Analysing the atoms in the water-ice molecules encasing the gases also gives an indication of the temperatures that persisted at the time of precipitation.

Currently, the oldest, continuous ice core ever drilled comes from the previous effort at Dome C called the European Project for Ice Coring in Antarctica (EPICA).

This ran from 1996 to 2004, and pulled up a 10cm-wide cylinder of ice that was 2,774m long.

What did this previous ice core reveal?

The old EPICA core contained an 800,000-year record of temperatures and atmospheric carbon dioxide.

These markers were seen to move in lock-step. Whenever the Earth went into an ice age and temperatures fell, the concentration of greenhouse gases in the atmosphere would also decline. And when the climate warmed back up again, the CO2 rose in parallel.

These cycles occurred roughly every 100,000 years in the EPICA core - a phasing that is most likely linked to slight shifts in the eccentricity of Earth's orbit (a larger or smaller ellipse) around the Sun.

But it is recognised from an alternative record of past climate, which has been deciphered from ocean sediments, that deeper back in time the ice age cycle was much shorter - at about every 41,000 years.

That is a period probably dominated by the way the Earth tilts back and forth on its axis. But why the switch occurred, no-one is really sure.

What could be the reason for the switch?

The orbital quirks described above change how much of the Sun's energy reaches the Earth, and it accounts for variations in global temperatures in the order of 1.5 degrees Celsius.

But ice ages - from their minimum to their maximum states - involve variations of six degrees. This means there have to have been amplification processes in play.

Differences in the mix and level of greenhouse gases in the atmosphere will no doubt be a part of the story, and the Beyond-EPICA ice core, if it it can reach back to 1.5 million years ago, will expose this particular contribution. There are certain to be additional factors, however.

"In my personal opinion, the best candidate is an internal mechanism in the climate system which has to do with changes in the ice volume on Earth," said Prof Olaf Eisen, the Beyond-EPICA project coordinator from Germany's Alfred-Wegener-Institute.

"If you change ice volume, you also change sea-level and ocean circulation. But something happened in what we call the Middle Pleistocene Transition.

"The drivers behind the MPT are still under debate and touch on the basic understanding of the climate system."

View Video Graph >>  https://www.bbc.co.uk/news/science-environment-47848344

Has Europe chosen the right location?

Many nations have been searching for a place to drill the oldest ice core, including America, Russia, China, Japan and Australia. Europe's is the first project to go into the implementation phase.

The site is helped enormously in terms of logistics by being close to an existing research base, but Little Dome C's selection was only approved after three years of careful survey work.

Teams dragged radar instruments back and forth across the ice to map the layers below. They even sank test boreholes to work out how warm it was likely to be at the base of the ice sheet.

One of the complexities is that heat coming up from the bedrock will melt away the bottom-most and oldest layers of ice. This is a very real danger the deeper the drilling goes, as the coldest temperatures are always found closest to the surface of the ice sheet.

"The core will be in 4m lengths when it comes up," explained Dr Rob Mulvaney from the British Antarctic Survey. "We'll cut it into 1m sections at Little Dome C and then move them to Concordia station itself.

"At the station we'll cut the sections in half, lengthways. One half we'll leave in Antarctica as a long-term archive (we won't have to pay freezer costs!), and the other half will come back to Europe for analysis."

https://www.bbc.co.uk/news/science-environment-47848344

 

 

[CaaC (John)+]

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Anak Krakatau: Collapsed volcano's tsunami simulated

Scientists have produced a new model to illustrate the December collapse of Indonesia's Anak Krakatau volcano and its subsequent tsunami.

The results indicate that 0.2-0.4 cu km of material on the southwestern flank of the volcano must have slid into the sea to produce the destructive waves.

The simulation matches well the high-water readings recorded at tide gauges on Sumatran and Javan coasts.

More than 400 people lost their lives in the disaster; 33,000 were displaced.

The event took nearly everyone by surprise. The dangers of a landslide-generated tsunami stemming from a volcanic eruption had been under-appreciated. Local populations certainly had no warning.

Scientists, also, were having to catch up, said  Prof David Tappin, who presented the new model here at the European Geosciences Union General Assembly.  Thinking had been strongly focused on the tsunamis from big earthquakes, the British Geological Survey and University College London scientist told reporters.

"Why is Anak Krakatau interesting? Because it's the first such event we've been able to investigate using all the modern technologies and understandings that have come about over the past 20 years," he explained.

"[These include] numerical tsunami modelling, particularly from non-seismic sources; satellite radar; high-resolution satellite photography before and after the event; and high-resolution seabed mapping."

Anak Krakatau's collapse occurred on the evening of 22 December, during a period of renewed eruptive activity.

A number of factors are thought to have precipitated what happened, including the height (340m), steepness and inherent weakness of the volcanic structure; and the fact that it had grown up close to - and had even migrated towards - the edge of a deep (220m) submarine trough.

When the flank went into the sea, it would have pushed out a big wave in front of it and sucked down the water surface immediately behind.

The model shows how the disturbance spread out across the Sunda Strait.

Prof Stephan Grilli, who led the modelling work at the University of Rhode Island, commented: "Numerical modelling of eruption-generated tsunamis is far less developed than for other tsunami mechanisms – such as earthquakes and landslides.

"The Anak Krakatau event is timely in that it should stimulate the development of new models that will underpin improved mitigation strategies."

The volcano has started to rebuild itself since the collapse. For a while, its old vent had been open to the sea, forming a small bay. This has now closed with the accumulation of new deposits.

The reconstruction, Prof Tappin believes, should alert the local authorities to the need to keep monitoring Anak Krakatau. Some sort of system that provides early warning of a repeat event is essential.

In addition, the British scientist says, the lessons learned need to travel beyond Indonesia to other volcanoes that share similarities with Anak Krakatau.

"There are more than 40 volcanoes near the sea in the world which are potentially Anak Krakataus. When we've confidently identified the mechanism then I would hope scientists at those volcanoes will be looking to see whether they have the same hazards."

https://www.bbc.co.uk/news/science-environment-47875777

 

 

[CaaC (John)+]

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Stonehenge: DNA reveals the origin of builders

 

The ancestors of the people who built Stonehenge travelled west across the Mediterranean before reaching Britain, a study has shown.

Researchers in London compared DNA extracted from Neolithic human remains found in Britain with that of people alive at the same time in Europe.

The Neolithic inhabitants appear to have travelled from Anatolia (modern Turkey) to Iberia before winding their way north.

They reached Britain in about 4,000BC.

Details have been  published in the journal Nature Ecology & Evolution.

The migration to Britain was just one part of a general, massive expansion of people out of Anatolia in 6,000BC that introduced farming to Europe.

Before that, Europe was populated by small, travelling groups which hunted animals and gathered wild plants and shellfish.

One group of early farmers followed the river Danube up into Central Europe, but another group travelled west across the Mediterranean.

DNA reveals that Neolithic Britons were largely descended from groups who took the Mediterranean route, either hugging the coast or hopping from island-to-island on boats.

When the researchers analysed the DNA of early British farmers, they found they most closely resembled Neolithic people from Iberia (modern Spain and Portugal). These Iberian farmers were descended from people who had journeyed across the Mediterranean.

From Iberia, or somewhere close, the Mediterranean farmers travelled north through France. They might have entered Britain from the west, through Wales or south-west England. Indeed, radiocarbon dates suggest that Neolithic people arrived marginally earlier in the west, but this remains a topic for future work.

In addition to farming, the Neolithic migrants to Britain appear to have introduced the tradition of building monuments using large stones known as megaliths. Stonehenge in Wiltshire was part of this tradition.

Although Britain was inhabited by groups of "western hunter-gatherers" when the farmers arrived in about 4,000BC, DNA shows that the two groups did not mix very much at all.

The British hunter-gatherers were almost completely replaced by the Neolithic farmers, apart from one group in western Scotland, where the Neolithic inhabitants had elevated local ancestry. This could have come down to the farmer groups simply having greater numbers.

"We don't find any detectable evidence at all for the local British western hunter-gatherer ancestry in the Neolithic farmers after they arrive," said co-author Dr Tom Booth, a specialist in ancient DNA from the Natural History Museum in London.

"That doesn't mean they don't mix at all, it just means that maybe their population sizes were too small to have left any kind of genetic legacy."

Co-author Professor Mark Thomas, from UCL, said he also favoured "a numbers game explanation".

Professor Thomas said the Neolithic farmers had probably had to adapt their practices to different climatic conditions as they moved across Europe. But by the time they reached Britain they were already "tooled up" and well-prepared for growing crops in a north-west European climate.

The study also analysed DNA from these British hunter-gatherers. One of the skeletons analysed was that of Cheddar Man, whose skeletal remains have been dated to 7,100BC.

He was the subject of a reconstruction unveiled at the Natural History Museum last year. DNA suggests that, like most other European hunter-gatherers of the time, he had dark skin combined with blue eyes.

Genetic analysis shows that the Neolithic farmers, by contrast, were paler-skinned with brown eyes and black or dark-brown hair.

Towards the end of the Neolithic, in about 2,450BC, the descendents of the first farmers were themselves almost entirely replaced when a new population - called the Bell Beaker people - migrated from mainland Europe. So Britain saw two extreme genetic shifts in the space of a few thousand years.

Prof Thomas said that this later event happened after the Neolithic population had been in decline for some time, both in Britain and across Europe. He cautioned against simplistic explanations invoking conflict, and said the shifts ultimately came down to "economic" factors, about which lifestyles were best suited to exploit the landscape.

Dr Booth explained: "It's difficult to see whether the two [genetic shifts] could have anything in common - they're two very different kinds of change. There's speculation that they're to some extent population collapses. But the reasons suggested for those two collapses are different, so it could just be coincidence."

https://www.bbc.co.uk/news/science-environment-47938188

 

 

 

[CaaC (John)+]

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Global Warming Confirmed By Planet Earth 'Skin Temperature Test'

Graeme Demianyk

Illustration of the Earth, half normal and half without water. This could represent the planet s fragility, and its vulnerability to the damages inflicted upon it by humans and other factors, including global warming.

Satellite measurements of the Earth’s “skin temperature” have confirmed that global warming is heating up the planet.

The infra-red sensitive system was used to record temperature trends from 2003 to 2017.

It showed a warming pattern consistent with other land-based measurements.

The satellite system records temperature at the surface of the ocean, land and snow-covered regions.

Its findings were compared with station-based data from the Goddard Institute for Space Studies Surface Temperature Analysis (Gistemp).

Dr Joel Susskind, from the American space agency Nasa’s Goddard Space Flight Centre, said: “Both data sets demonstrate the Earth’s surface has been warming globally over this period, and that 2016, 2017, and 2015 have been the warmest years in the instrumental record, in that order.”

The results are published in the journal Environmental Research Letters.

Co-author Dr Gavin Schmidt, also from the Goddard Institute, said: “Interestingly, our findings revealed that the surface-based data sets may be underestimating the temperature changes in the Arctic.

© KevinHyde via Getty Images Planet Earth Overheating because of Global Warming and the Greenhouse Effect - Australasia, Australia and Asia shown on the globe. This is a full set of images with all options available.

“This means the warming taking place at the poles may be happening more quickly than previously thought.”

https://www.msn.com/en-gb/news/techandscience/global-warming-confirmed-by-planet-earth-skin-temperature-test/ar-BBW0utI?ocid=chromentp

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[CaaC (John)+]

Antarctica: Thousands of emperor penguin chicks wiped out

By Jonathan Amos

BBC Science Correspondent

Thousands of emperor penguin chicks drowned when the sea-ice on which they were being raised was destroyed in severe weather.

The catastrophe occurred in 2016 in Antarctica's Weddell Sea.

Scientists say the colony at the edge of the Brunt Ice Shelf has collapsed with adult birds showing no sign of trying to re-establish the population.

And it would probably be pointless for them to try as a giant iceberg is about to disrupt the site.

The dramatic loss of the young emperor birds is reported by a team from the British Antarctic Survey (BAS).

Drs Peter Fretwell and Phil Trathan noticed the disappearance of the so-called Halley Bay colony in satellite pictures.

It is possible even from 800km up to spot the animals' excrement or guano, on the white ice and then to estimate the likely size of any gathering.

But the Brunt population, which had sustained an average of 14,000 to 25,000 breeding pairs for several decades (5-9% of the global population), essentially disappeared overnight.

Emperors are the tallest and heaviest of the penguin species and need reliable patches of sea-ice on which to breed, and this icy platform must persist from April, when the birds arrive, until December, when their chicks fledge.

If the sea-ice breaks up too early, the young birds will not have the right feathers to start swimming.

This appears to have been what happened in 2016.

Strong winds hollowed out the sea-ice that had stuck hard to the side of the thicker Brunt shelf in its creeks, and never properly reformed. Not in 2017, nor in 2018.

Dr Fretwell told BBC News: "The sea-ice that's formed since 2016 hasn't been as strong. Storm events that occur in October and November will now blow it out early. So there's been some sort of regime change. Sea-ice that was previously stable and reliable is now just untenable."

The BAS team believes many adults have either avoided breeding in these later years or moved to new breeding sites across the Weddell Sea. A colony some 50km away, close to the Dawson-Lambton Glacier, has seen a big rise in its numbers.

Quite why the sea-ice platform on the edge of the Brunt shelf has failed to regenerate is unclear. There is no obvious climate signal to point to in this case; atmospheric and ocean observations in the vicinity of the Brunt reveal little in the way of change.

But the sensitivity of this colony to shifting sea-ice trends does illustrate, says the team, the impact that future warming in Antarctica could have on emperor penguins in particular.

Research suggests the species might lose anywhere between 50% and 70% of its global population by the end of this century if sea-ice is reduced to the extent that computer models envisage.

Dr Trathan said: "What's interesting for me is not that colonies move or that we can have major breeding failures - we know that. It's that we are talking here about the deep embayment of the Weddell Sea, which is potentially one of the climate change refugia for those cold-adapted species like emperor penguins.

"And so if we see major disturbances in these refugia - where we haven't previously seen changes in 60 years - that's an important signal."

Whether the Halley Bay colony specifically really had a future is a moot point.

The Brunt Ice Shelf is being split apart by a developing crack.

This chasm will eventually calve an iceberg the size of Greater London into the Weddell Sea, and any sea-ice stuck to the berg's edge may break up in the process.

The colony could have been doomed regardless of what happened in 2016.

Drs Peter Fretwell and Phil Trathan report their investigation in the journal Antarctic Science.

https://www.bbc.co.uk/news/science-environment-48041487

[CaaC (John)+]

Science & Environment

Climate change being fuelled by soil damage - report

VIDEO >> https://www.bbc.co.uk/news/science-environment-48043134

Climate change can't be halted if we carry on degrading the soil, a report will say.

There's three times more carbon in the soil than in the atmosphere – but that carbon's being released by deforestation and poor farming.

This is fuelling climate change – and compromising our attempts to feed a growing world population, the authors will say.

Problems include soils being eroded, compacted by machinery, built over, or harmed by over-watering.

Hurting the soil affects the climate in two ways: it compromises the growth of plants taking in carbon from the atmosphere, and it releases soil carbon previously stored by worms taking leaf matter underground.

The warning will come from the awkwardly-named IPBES – the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services - a panel studying the benefits of nature to humans.

The body, which is meeting this week, aims to get all the world’s governments singing from the same sheet about the need to protect natural systems.

IPBES will formally release its report on Monday 6 May.

• Climate change: Where we are in seven charts
• Is soil the secret to slowing climate change?
• Environment in multiple crises - report

About 3.2 billion people worldwide are suffering from degraded soils, said IPBES chairman Prof Sir Bob Watson.

"That's almost half of the world population. There’s no question we are degrading soils all over the world. We are losing from the soil the organic carbon and this undermines agricultural productivity and contributes to climate change. We absolutely have to restore the degraded soil we’ve got."

Prof Watson previously led the Inter-governmental Panel on Climate Change (IPCC).

"Governments have focused on climate change far more than they have focused on loss of biodiversity or land degradation. All three are equally important to human wellbeing."

Soil expert Prof Jane Rickson from Cranfield University, UK, added: "The thin layer of soil covering the Earth's surface represents the difference between survival and extinction for most terrestrial life.

"Only 3% of the planet's surface is suitable for arable production and 75 billion tonnes of fertile soil is lost to land degradation every year." She said soils form at a rate of 1cm in 300 years.

There's uncertainty about the exact level of global soil degradation. But the major hotspots are reported to be in South America, where forests are being felled; sub-Saharan Africa; India and China. Soil scientists in both the biggest Asian nations are worried that their ability to grow their own food may be compromised.

In the US, some soils are being restored as forests take over poor quality land previously worked by small farmers, but others are still being degraded.

The UK is not immune either. Some maize fields in south-west England suffer major soil loss with heavy rainfall because growing maize leaves bare soil exposed. Heavy rain is more likely under climate change. Erosion is also a long-standing issue in the fertile Fens, where, on dry windy days, peaty soil particles sometimes form a kind of smog called the "Fen Blow".

Peat has a high carbon content – and a recent paper suggests there’s far more carbon being lost from peatlands than previously thought.

And on the chalky hills of southern England, chemical-intensive crop farming is said to have caused the loss of over a foot of soil in some places.

Soils are "incredibly important" for our well-being, said Dr Joanna Clark from Reading University.

"We all know that crops are grown in soil, but soils are important for climate change as well. There's three times more carbon stored in soil than there is in the atmosphere. So imagine if all that carbon was released, we’d get runaway climate change. So we need to keep the carbon in the soil."

The simplest way to protect soils while combating climate change is to let forests grow back. This option is favoured by fans of re-wilding.

But some farmers believe they can continue to produce food by changing the way they farm to enhance the soil.

Brexit could give the UK greater flexibility on how to spend public money on farming - enabling much more leeway to reward farmers for capturing carbon in the earth. But there are more than 700 soil types in the UK alone, so it won’t be simple.

https://www.bbc.co.uk/news/science-environment-48043134

[CaaC (John)+]

Science & Environment

Denisovans: Primitive humans lived at high altitudes

Scientists have found evidence that an ancient species of human called Denisovans lived at high altitudes in Tibet.

The ability to survive in such extreme environments had previously been associated only with our species - Homo sapiens.

The ancient ancestor seems to have passed on a gene that helps modern people cope at high elevations.

Details of the study are published in the journal Nature.

The Denisovans were a mysterious human species living in Asia before modern humans like us expanded across the world tens of thousands of years ago.

Until recently, the only fossils came from a few fragments of bone and teeth from a single site in Siberia - Denisova Cave.

But DNA had shown that they were a distinct branch of the human family.

Now, scientists have identified the first Denisovan fossil from another site. It's a mandible (lower jawbone) discovered in 1980 at Baishiya Karst Cave, 3,280m up on the Tibetan Plateau.

A technique called uranium-series dating was used on carbonate deposits on the bone. This yielded a date of 160,000 years ago for the mandible.

Co-author Jean Jacques Hublin, from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, said finding evidence of an ancient - or archaic - species of human living at such high elevations was a surprise.

"When we deal with 'archaic hominins' - Neanderthals, Denisovans, early forms of Homo sapiens - it's clear that these hominins were limited in their capabilities to dwell in extreme environments.

"If you look at the situation in Europe, we have a lot of Neanderthal sites and people have been studying these sites for a century-and-a-half now.

"The highest sites we have are at 2,000m altitude. There are not many, and they are clearly sites where these Neanderthals used to go in summer, probably for special hunts. But otherwise, we don't have these types of sites."

Of the Denisovans on the Tibetan Plateau, he said: "It's a plateau... and there are obviously enough resources for people to live there and not just come occasionally."

While the researchers could not find any traces of DNA preserved in this fossil, they managed to extract proteins from one of the molars, which they then analysed applying something called ancient protein analysis.

"Our protein analysis shows that the Xiahe mandible belonged to a hominin population that was closely related to the Denisovans from Denisova Cave," said co-author Frido Welker, from the University of Copenhagen, Denmark.

The discovery may explain why individuals studied at Denisova Cave had a gene variant known to protect against hypoxia (oxygen deficiency) at high altitudes. This had been a puzzle because the Siberian cave is located just 700m above sea level.

Present-day Sherpas, Tibetans and neighbouring populations have the same gene variant, which was probably acquired when Homo sapiens mixed with the Denisovans thousands of years ago.

In fact, the gene variant appears to have undergone positive natural selection (which can result in mutations reaching high frequencies in populations because they confer an advantage).

"We can only speculate that living in this kind of environment, any mutation that was favourable to breathing an atmosphere impoverished in oxygen would be retained by natural selection," said Prof Hublin.

"And it's a rather likely scenario to explain how this mutation made its way to present-day Tibetans."

https://www.bbc.co.uk/news/science-environment-48107498

[CaaC (John)+]

Science & Environment

Gravitational waves hunt now in overdrive

VIDEO >> https://www.bbc.co.uk/news/science-environment-48137011

Scientists working to detect gravitational waves switched on their instruments for a third time at the beginning of April and immediately began to register events that could be interpreted as cosmic collisions. All five trigger events still need confirmation. The BBC's Roland Pease examines how telescopes worldwide are helping.

The alert on Mansi Kasliwal's phone went off at two in the morning. Shrugging off the sleep, she squinted at the message. It was from LIGO, the Nobel Prize-winning scientific collaboration that operates gravitational wave detectors.

A far-off violent event had sent ripples in space-time through the Universe, to be picked up by LIGO's sensor in Louisiana, and it looked from the data like there should be visible "fireworks", too.

Thanks to the smartphone revolution, she could react without leaving her bed. A few taps on the screen, and the Zwicky Transient Facility, a robotic telescope on Mount Palomar, was reprogrammed to start the hunt.

LIGO, the Laser Interferometer Gravitational-Wave Observatory, and its European counterpart, VIRGO, have just completed upgrades that mean they should be spotting space-distorting events several times each week - collisions of black holes, of neutron stars, and even more exotic phenomena.

And since they started running again at the start of April, expectations are holding up: two in the second week; three last week.

The first three, still to be formally confirmed, were probably collisions between black holes, like the first, Nobel-anointed event detected in 2015.

It was the next, on 25 April, that woke Mansi Kasliwal up. The gravitational ripples hinted at the involvement of neutron stars, which would be engulfed in a scorching nuclear flame as they devoured each other and became one.

The radio, optical, X-ray and gamma-ray colours would reveal new details about these normally secretive objects. But before the specialist telescopes could zoom in on the action, astronomers needed to know exactly where to look.

That is where the Zwicky Transient Facility (ZTF) comes in, a new instrument able to scan large swathes of the sky swiftly for anything new and unusual.

The 25 April "candidate" event was going to test that capacity. With LIGO's second detector temporarily out of action (the one in Hanford, Washington State), LIGO and VIRGO could only narrow the search to a quarter of the entire sky: somewhere in that vast darkness, a new spark could be brightly shining, but beginning to fade.

Gravitational waves - Ripples in the fabric of space-time

ZTF has the ability to photograph an area about 14 Moons by 14 Moons in just 30 seconds and see anything down to 150,000 times dimmer than the faintest star visible to the human eye. In a little over two hours, it has scoured this whole target area, before moving on to a new sector.

Meanwhile, astronomers across the planet were dialling into teleconferences. Which are the best telescopes to make the detailed observations? Where is it daylight, and where were the skies dark?

ZTF was so effective, it detected several hundred thousand bright points in the sky that had not been there the night before. "The Universe is an extremely dynamic place; it's not the same every time you look at it," Mansi Kasliwal told the BBC's Science in Action programme on the World Service.

"In fact, every second a supernova goes off somewhere in the Universe."

On top of that, there are stellar flares, galactic flashes, and comets or asteroids hoving into view, plus stars that had shifted position almost imperceptibly since the last viewing.

Machine learning algorithms whittled that fog of activity down to just two candidates whose coordinates were shared with 2,000 other astronomers to scrutinise more closely.

It was while Mansi awaited their reports that the system kicked into action for the second time in 30 hours.

Another alert from LIGO, again involving neutron stars, though in this case possibly a single neutron star being swallowed by a black hole.

"My team just froze; we were stunned by this - we hadn't slept, but also we didn't know if such a thing could exist," she recalls.

This time, all three gravitational wave detectors were operational, tightening the location, but the signal was weaker and more ambiguous, perhaps not even genuine.

Nevertheless, a second search had to be started.

It was morning in California, so the Zwicky telescope was no use. But Mansi Kasliwal could call on the services of telescopes in the international network she directs - GROWTH (for Global Relay of Observatories Watching Transients Happen). The hunt was on again, from Hawaii, Chile and India.

"This would be the discovery we have all been waiting for in the new phase of the LIGO-VIRGO collaboration," says astrophysicist Samaya Nissanke of Amsterdam University in the Netherlands.

The initial analysis gave just a 13% chance the waves were stirred up by a neutron star diving into a black hole, but also a 14% chance it was just a glitch down here on Earth. And even if it was real, a really massive black hole would swallow the dead star so thoroughly it would leave no visible trace.

"There is this sweet spot, though, where we expect there will be some matter disrupted just as it gets swallowed by the black hole," Samaya Nissanke told the BBC. "And it is this matter that would generate the electromagnetic signals we might see."

April was an amazing month for black hole science, with the first image of a black hole also being released

__________________________________________________________________

Time is of the essence.

Gamma-rays and X-rays seen from satellites would fade in hours as the nuclear flame cools; the optical signal might last days, and the radio glow could go on for weeks.

But while astronomers on other projects are happy, to an extent, to surrender their valuable telescope time to others observing these "targets of opportunity", they want to know it will be used well. Hence, the need for rapid follow-up scans to pinpoint plausible targets.

When LIGO and VIRGO found their first "kilonova" due to a pair of neutron stars in 2017, all the cards fell in place: the location was precise, the signal strong, and dozens of telescopes captured events across the spectrum and over weeks to give an unprecedented view of the violent Universe.

This past fortnight, astronomers have had a cold dose of reality. The two targets they found on the sky that might have been associated with the 25 April event turned out to be ordinary supernovae, dying stars, which could have been thrilling two decades ago but are routine in modern observations. And that leaves astronomers in the dark as to what happened to set the gravity detectors off.

As for the second event - bad weather has hampered follow-up observations.

According to Mansi Kasliwal, there is one tantalising candidate that remains to be examined. But time is running out.

The astronomers are not disheartened, however.

"It was a let-down in terms of the final result," says Mansi Kasliwal of the first search. "But it is really a celebration in terms of the technological feat that we scanned a quarter of the sky and could pick out some candidates in just a few hours."

Samaya Nissanke agrees - it was a dress rehearsal that shows how quickly star-gazers can respond when gravitational waves pass by.

"It's just the reality that we really are seeing around a candidate trigger per week, which could include a few neutron star mergers this year," she says.

"We've stepped into an entirely new realm thanks to the hard work of observers like Mansi."

https://www.bbc.co.uk/news/science-environment-48137011

[CaaC (John)+]

Geology study finds massive volcanic blast

Research at the British Geological Survey (BGS) in Edinburgh is warning that we still don't know enough when it comes to predicting and preparing for major volcanic eruptions.

Dr Julia Crummy has based her conclusion on years spent researching the Volcán de Colima in Mexico.

Standing over 12,470ft (3,800m) high, it is one of the most active volcanoes in North America.

Colima has erupted every other year, on average, since 1900. Its last phase of eruptions lasted from 2013 to 2017.

In 2015 the fall of ash was so severe that hundreds of people were evacuated from their homes and the local airport was closed temporarily. There were more evacuations the following year.

Dr Crummy says the last really big explosion was in 1913.

"There was a civil war going on at the time and they actually thought it was cavalry," she says. "It produced a really huge ash cloud that rose up to about 23km (14 miles).

"Pyroclastic flows travelled 15km (9 miles) from the volcano and ashfall was reported in Guadalajara. That's about 160km (99 miles) away."

Today, more than 500,000 people live within 30km (17 miles) of Colima. Extensive plans are in place to safeguard them in the event of another big explosion.

But how big will that be?

Prehistoric eruptions

The historical record of Colima's activity only begins after the Spanish conquistadors arrived in 1519.

Dr Crummy has been using geology to look back further by examining layers of ash left behind by prehistoric eruptions.

"Charcoal samples for dating have enabled us to identify that these span the past 30,000 years.

"By looking at the minerals in the samples we can look at how behaviour has changed over time."

By establishing the thickness of each layer Dr Crummy was able to build a numerical model of how large the eruptions had been.

She modelled the volume and magnitude of five prehistoric explosive events between 4,400 and 6,000 years ago.

Her most surprising finding is that some were an order of magnitude bigger than previously thought.

Instead of throwing a cubic kilometre of debris into the atmosphere it was 10 times as much.

That is 10 times larger than the explosions on which the current plans and hazard maps are based.

"That's not to say the hazard maps are wrong," Dr Crummy says.

"They're based on a worst case scenario using known historical data, which is absolutely fine.

"But what we're doing is highlighting the fact that actually, if you look at the geological record and extend beyond the historical over the last 10,000 years or so, we can see there have been much larger eruptions.

"So it's about awareness."

This study of a single volcano has far wider implications.

An estimated 800 million people live within 100km (62 miles) of a potentially active volcano.

Writing in the Journal of Applied Volcanology, Dr Crummy says it means science's understanding of past volcanic eruptions is still limited.

And in many places, the geological record is less well preserved than at Colima.

The eruption of Eyjafjallajökull in Iceland disrupted air traffic as recently as 2010 but much of the geological evidence has already been washed away.

Dr Crummy's research was funded by the Natural Environment Research Council, the BGS and the Smithsonian Institute.

Colima's cone is closely monitored - you can do it yourself on a  live webcam

This week increasing seismic activity raised the alert state from green to yellow.

That means people are not being allowed within 8km (5 miles) of the volcano.

So, for the time being, tourists are prevented from taking snaps of Colima's vivid contrast between snow and fire.

https://www.bbc.co.uk/news/uk-scotland-edinburgh-east-fife-48148736

 

[CaaC (John)+]

US climate objections sink Arctic Council accord in Finland

US objections to the wording on climate change prevented Arctic nations signing a joint statement at a summit in Finland, delegates said.

It is the first time such a statement has been cancelled since the Arctic Council was set up in 1996.

A Finnish delegate, Timo Koivurova, said: "the others felt they could not water down climate change sentences".

There is international concern that Arctic temperatures are rising twice as fast as in the rest of the world.

On Monday, US Secretary of State Mike Pompeo addressed the forum in Rovaniemi, northern Finland, with a speech welcoming the melting of Arctic sea ice, rather than expressing alarm about it.

"Steady reductions in sea ice are opening new passageways and new opportunities for trade," he said. "This could potentially slash the time it takes to travel between Asia and the West by as much as 20 days."

"Arctic sea lanes could become the 21st-Century Suez and Panama Canals," Mr Pompeo said.

At short notice, he cancelled talks with German Chancellor Angela Merkel in Berlin on Tuesday, in a surprise move.

Environmental warning

Scientists and environmental groups warn that the retreat of Arctic sea ice threatens polar bears and marine species, but also contributes to rising sea levels, adding to the risk of coastal flooding.

They also warn of a major pollution risk if energy and transport firms find it easier to exploit the pristine Arctic wilderness.

The Arctic Council consists of the United States, Canada, Russia, Finland, Norway, Denmark, Sweden and Iceland. It meets every two years to address economic and environmental challenges in the Arctic.

Sources at the forum told Reuters news agency that the US shunned the joint statement because of wording stating that climate change posed a serious threat to the Arctic.

In 2017 US President Donald Trump pulled out of the 2015 Paris climate accord signed by almost 200 governments. The accord aims to limit a rise in average global temperatures to "well below" 2C (3.6F) above pre-industrial levels by the end of the century.

At the Rovaniemi meeting, Mr Pompeo also attacked what he called "aggressive behaviour" by China and Russia in the Arctic region.

https://www.bbc.co.uk/news/world-europe-48185793

[CaaC (John)+]

Climate change: Scientists test radical ways to fix Earth's climate

Scientists in Cambridge plan to set up a research centre to develop new ways to repair the Earth's climate.

It will investigate radical approaches such as refreezing the Earth's poles and removing CO2 from the atmosphere.

The centre is being created because of fears that current approaches will not on their own stop dangerous and irreversible damage to the planet.

The initiative is the first of its kind in the world and could lead to dramatic reductions in carbon emissions.

The initiative is coordinated by the government's former chief scientific adviser, Prof Sir David King.

"What we do over the next 10 years will determine the future of humanity for the next 10,000 years.

There is no major centre in the world that would be focused on this one big issue," he told BBC News.

Some of the approaches described by Sir David are often known collectively as geoengineering.

What we do over the next 10 years will determine the future of humanity for the next 10,000 years.

Prof Sir David King, Ex-Government Chief Scientist

Dr Emily Shuckburgh, a climate scientist at Cambridge University, said the new centre's mission would be to "solve the climate problem".

"It has to be. And we can't fail on it," she said.

The Centre for Climate Repair is part of the university's Carbon Neutral Futures Initiative, led by Dr Shuckburgh.

It will bring together scientists and engineers with social scientists.

"This really is one of the most important challenges of our time, and we know we need to be responding to it with all our efforts," Dr Shuckburgh told BBC News.

Refreezing the poles

One of the most promising ideas for refreezing the poles is to "brighten" the clouds above them.

The idea is to pump seawater up to tall masts on uncrewed ships through very fine nozzles.

This produces tiny particles of salt which are injected into the clouds, which makes them more widespread and reflective, and so cool the areas below them.

Recycling CO2

Another new approach is a variant of an idea called carbon capture and storage (CCS).

CCS involves collecting carbon dioxide emissions from coal or gas-fired power stations or steel plants and storing it underground.

Prof Peter Styring, of the University of Sheffield, is developing a carbon capture and utilisation (CCU) pilot scheme with Tata Steel in Port Talbot in South Wales which effectively recycles CO2.

The scheme involves setting up a plant on-site which converts the firm's carbon emissions into fuel using the plant's waste heat, according to Prof Styring.

"We have a source of hydrogen, we have a source of carbon dioxide, we have a source of heat and we have a source of renewable electricity from the plant," he told BBC News.

"We're going to harness all those and we're going to make synthetic fuels."

Ocean greening

Other ideas the centre would explore include greening the oceans so they can take up more CO2.

Such schemes involve fertilising the sea with iron salts which promote the growth of plankton.

Previous experiments have shown that they don't take up sufficient CO2 to make the scheme worthwhile and might disrupt the ecosystem.

But according to Prof Callum Roberts of York University, approaches that are currently thought beyond the pale now have to be considered and, if possible, made to work.

This is because the alternative of damaging and potentially irreversible climate change is considered beyond the pale.

"Early in my career, people threw their hands up in horror at suggestions of more interventionist solutions to fix coral reefs," Prof Roberts said.

"Now they are looking in desperation at an ecosystem that will be gone at the end of the century and now all options are on the table".

The options include genetically engineering heat-resistant coral or dumping chemicals into the sea to make the sea less acidic.

"At the moment, I happen to think that harnessing nature to mitigate climate change is a better way to go. But I do see the legitimacy of exploring [more radical] options as a means of steering us towards a better future," Prof Roberts said.

Thinking the unthinkable

Such ideas have many potential downsides and may prove to be unfeasible.

But Peter Wadhams, a professor of ocean physics at Cambridge University, said that they should be properly assessed to see if the downsides can be overcome because he believes that reduction of CO2 emissions on its own won't be enough.

• What is in the Paris climate agreement?

"If we reduce our emissions all we are doing is making the global climate warmer a bit more slowly. That is no good because it's already too warm and we have already got too much CO2 in the atmosphere," Prof Wadhams said.

"So climate repair can actually take it out of the atmosphere. We can get the level down below what it is now and actually cool the climate bringing it back to what it was before global warming," he added.

https://www.bbc.co.uk/news/science-environment-48069663

 

 

Edited May 10, 2019 by CaaC - John
Spelling corrections

[CaaC (John)+]

Jakobshavn Isbrae: Mighty Greenland glacier slams on brakes

European satellites have detailed the abrupt change in behaviour of one of Greenland's most important glaciers.

In the 2000s, Jakobshavn Isbrae was the fastest flowing ice stream on the island, travelling at 17km a year.

As it sped to the ocean, its front end also retreated and thinned, dropping in height by as much as 20m year.

But now it's all change. Jakobshavn is travelling much more slowly, and its trunk has even begun to thicken and lengthen.

"It's a complete reversal in behaviour and it wasn't predicted," said Dr Anna Hogg from Leeds University and the UK Centre for Polar Observation and Modelling (CPOM).

"The question now is: what's next for Jakobshavn? Is this just a pause, or is it a switch-off of the dynamic thinning we've seen previously?"

The glacier is sited in southwest Greenland. It's famous for its spectacular production of icebergs - colossal blocks calve from its terminus and drift down its fjord, out into Disko Bay and onwards to the North Atlantic.

More than likely, it was Jakobshavn that spawned the iceberg that sank the Titanic.

Scientists' interest in the glacier lies in its role as a drainage outlet for the Greenland Ice Sheet. It's a key channel for the export of ice that can then raise global sea levels.

The rapid flow, thinning and retreat of Jakobshavn's front end in the mid to late 2000s were probably driven by warm ocean water from Disko Bay getting into the fjord and attacking the glacier from below.

The phase change, scientists think, may be related to very cold weather in 2013. This would have resulted in less meltwater coming off the glacier, which in turn might have choked the mechanism that pulls warm ocean water towards Jakobshavn.

"Fjord overturning, the circulation that draws warm ocean water in from Disko Bay to melt the glacier at its base is, in part, forced by surface melting on the Greenland Ice Sheet. If you don't get a lot of fresh, cold meltwater going into the fjord, this circulation is weaker," said Dr Hogg.

The Leeds researcher has been using a suite of European satellites to monitor Jakobshavn, including the EU's Sentinels 1 and 2 and the German national TerraSAR-X mission.

Another useful tool has been the radar altimeter on the European Space Agency's Cryosat platform.

This has a very high-resolution "swath" mode that has allowed Dr Hogg to track elevation changes on the glacier's narrow trunk.

Where previously this was dropping in height by 20m a year, it's now thickening by 20m a year.

"All this is a reminder of how unpredictable glaciers can be," she told BBC News. "We didn't predict this change in behaviour, and if Jakobshavn does start thinning and retreating again - we can't predict when that will happen.

"The rate of sea-level contribution from Greenland has slowed in recent years and it's because some of the biggest ice evacuators like Jakobshavn aren't contributing as much as they used to."

Dr Hogg was speaking here at the Esa's Living Planet Symposium, Europe's largest Earth observation conference.

https://www.bbc.co.uk/news/science-environment-48265217

 

[CaaC (John)+]

Straws: UK government to bring in new controls on plastic

By David ShukmanScience editor

In a bid to limit ocean pollution, the UK government will introduce new controls on single-use plastic items next year.

The measures cover plastic straws, plastic drinks stirrers and plastic cotton buds in England from April 2020.

Only plastic drinks stirrers will be totally banned from sale - currently, 316 million are used a year.

Environmental groups have praised the move but say the government needs to take far more decisive action.

How will plastic straws be affected?

The government press release announcing the new restrictions talks of "a ban on the supply of plastic straws" but in reality, the aim is instead to restrict their availability.

Shops including supermarkets will not be allowed to sell the straws but they will on sale by registered pharmacies in stores and online.

That's because disabled groups have highlighted how straws are essential for everyday life and that a total ban could lead to the risk of dehydration.

According to the announcement, bars and restaurants will not be allowed to display plastic straws or automatically hand them out but they will be able to provide them if people ask.

When asked who could request a straw, a spokesperson for the environment ministry Defra said: "Anyone can ask for a straw and be given one without needing to prove a disability - we've been working with disabled groups so that they don't feel stigmatised."s

What else is covered by the new controls?

Plastic stirrers will be subject to a total ban.

However plastic-stemmed cotton buds, although restricted from general sale to the public, will still be available.

Medical and scientific laboratories will be able to buy them for use in research and for forensic tasks in criminal investigations.

Defra reckons 1.8bn plastic-stemmed cotton buds are used and thrown away every year in England.

Haven't we heard this before?

The government has been considering action on single-use plastic items since the public reaction to David Attenborough's landmark Blue Planet II documentaries nearly two years ago.

At the time, Environment Secretary Michael Gove described being haunted by the image of marine life harmed by plastic and launched consultations on a series of measures to curb single-use items.

As part of today's announcement that controls would come into effect next April, Mr Gove said: "These items are often used for just a few minutes but take hundreds of years to break down, ending up in our seas and oceans and harming precious marine life.

"So today I am taking action to turn the tide on plastic pollution, and ensure we leave our environment in a better state for future generations."

This comes as Scotland is also taking steps to restrict or ban plastic straws, and plastic-stemmed cotton buds.

The Welsh government has also been considering similar measures.

Earlier this week the European Union formally adopted a plan to ban a longer list of items including plastic straws, plastic cutlery and plastic plates by 2021.

Green groups say they are pleased that the government is taking action but many are critical that the measures do not go further.

WWF called for a ban on all "avoidable single-use plastic" by 2025 and said ministers needed "to really ramp up their commitments".

The Marine Conservation Society, which said it found on average 17 cotton buds for every 100m of beach in England, said Mr Gove needed to do more to reduce plastic consumption and increase recycling rates.

The Campaign to Protect Rural England (CPRE) said Mr Gove should phase out single-use items altogether and warned that replacements made with alternative materials might still be harmful.

The move comes as many takeaway restaurants are already introducing biodegradable alternatives.

https://www.bbc.co.uk/news/science-environment-48358002

 

Edited May 22, 2019 by CaaC - John
Spelling corrections

[CaaC (John)+]

Humans started walking on two feet because of LIGHTNING, bizarre study claims

Lightning triggered by spectacular cosmic blasts millions of years ago holds the key to why humans walk on two feet, according to new research.

The bombardment of electric storms forced our ancestors out of the trees by razing forests to the ground - making them forge a future down below.

It is what led to homo sapiens having hands free to build cathedrals, design rockets and snap iPhone selfies, say, astronomers.

Lead author Professor Adrian Melott, of the University of Kansas, explained: "It is thought there was already some tendency for hominins to walk on two legs, even before this event.

"But they were mainly adapted for climbing around in trees. After this conversion to savanna, they would much more often have to walk from one tree to another across the grassland, and so they become better at walking upright.

"They could see over the tops of grass and watch for predators. It is thought this conversion to savanna contributed to bipedalism as it became more and more dominant in human ancestors."

Exactly why and when our ancestors stood upright and started moving around on two feet is still shrouded in mystery.

The reason early humans, or hominins, abandoned a life on all fours has been debated by evolutionary experts decades. It is one of the defining traits of our species.

There is fossil evidence the iconic stance, not found in any other ape, began at least six million years ago.

Now, a cutting-edge study published in the Journal of Geology suggests for the first time that it was triggered by lightning-fuelled wildfires.

Prof Melott's team say ancient exploding stars, or supernovae, gave 'proto-humans' no choice.

They began blitzing Earth with energy up to eight million years ago - peaking around 5.4 million years later.

It initiated an avalanche of electrons in the lower atmosphere - setting off a chain of events culminating in homo habilis.

© Provided by Trinity Mirror Shared Services Limited The study suggests that bipedalism arose when ancient supernovae caused lightning that burned Earth's forests

Dubbed 'handyman', this is believed to be the earliest human species to leave tools - and leave Africa.

In Frankenstein, the monster is sparked into life after Mary Shelley's fictional scientists hones the power of lightning.

Now Prof Melott and colleagues say our own mobility can be traced back to the extraordinary physical phenomenon - indirectly, at least.

Based on a "telltale" type of metal which lines the world's sea beds, it is known huge stars exploded 163 light years away between five and 2.5 million years ago.

The deposits of iron-60 were caused by supernovae in our near neighbourhood.

This was during the transition from the warmer Pliocene Epoch to the beginning of the Ice Age.

Prof Melott said: "We calculated the ionisation of the atmosphere from cosmic rays which would come from a supernova about as far away as the iron-60 deposits indicate.

"It appears this was the closest one in a much longer series. We contend it would increase the ionisation of the lower atmosphere by 50-fold.

"Usually, you don't get lower-atmosphere ionization because cosmic rays don't penetrate that far.

"But the more energetic ones from supernovae come right down to the surface, so there would be a lot of electrons being knocked out of the atmosphere."

This meant an abundance of electrons would form more pathways for lightning strikes, say Prof Melott and co-author prof Brian Thomas, of Washburn University, Kansas.

Prof Melott said: "The bottom mile or so of the atmosphere gets affected in ways it normally never does.

"When high-energy cosmic rays hit atoms and molecules in the atmosphere, they knock electrons out of them - so these electrons are running around loose instead of bound to atoms.

"Ordinarily, in the lightning process, there is a buildup of voltage between clouds or the clouds and the ground but current can't flow because not enough electrons are around to carry it.

"So, it has to build up high voltage before electrons start moving. Once they are moving, electrons knock more electrons out of more atoms, and it builds to a lightning bolt.

"But with this ionisation, that process can get started a lot more easily, so there would be a lot more lightning bolts."

This spike set off wildfires around the world. The theory is supported by the discovery of carbon deposits found in soils that correspond with the timing.

Prof Melott said: "The observation is there is a lot more charcoal and soot in the world starting a few million years ago.

"It is all over the place, and nobody has any explanation for why it would have happened all over the world in different climate zones. This could be an explanation.

"That increase in fires is thought to have stimulated the transition from woodland to savanna in a lot of places - where you had forests, now you had mostly open grassland with shrubby things here and there.

"That is thought to be related to human evolution in northeast Africa. Specifically, in the Great Rift Valley where you get all these hominin fossils."

No such event is likely to occur again anytime soon. The nearest star capable of exploding into a supernova in the next million years is Betelgeuse, some 652 light years from Earth.

Added Prof Melott: "Betelgeuse is too far away to have effects anywhere near this strong. So, don't worry about this. Worry about solar proton events. That is the danger for us with our technology - a solar flare that knocks out electrical power. Just imagine months without electricity."

https://www.msn.com/en-gb/news/offbeat/humans-started-walking-on-two-feet-because-of-lightning-bizarre-study-claims/ar-AAC1XYd