Tag Archives: layer

Antarctic ozone hole at its smallest recorded size ever

The ozone hole over the Antarctic registered its smallest annual peak on record (tracking began in 1982) according to an announcement by the National Oceanic and Atmospheric Administration (NOAA) and NASA on Monday.

Image credits NASA Ozone Watch.

Each year, an ozone hole forms during the Southern Hemisphere’s late winter as the solar rays power chemical reactions between the ozone molecules and man-made compounds of chlorine and bromine. Governments around the world are working together to cut down on the ozone-depleting chemicals that created this hole, and it definitely helps.

However, the two agencies warn that we’re still far from solving the problem for good. The small peak in the ozone hole’s surface likely comes from unusually mild temperatures in that layer of the atmosphere seen during this year, they add.

Good but not done

NASA and NOAA explain that the ozone hole consists of an area of heavily-depleted ozone in the upper reaches of the stratosphere. This hole is centered on Antarctica, between 7 and 25 miles (11 and 40 kilometers) above the surface. At its largest recorded size in 2019, the hole extended for 6.3 million square miles (September 8) and then shrank to less than 3.9 million square miles (during the rest of September and October). While that definitely sounds like and is a lot of surface, it’s better than it used to be.

“During years with normal weather conditions, the ozone hole typically grows to a maximum of about 8 million square miles,” the agencies said in a news release.

It’s the third time we’ve seen a similar phenomenon — weather systems slowing down stratospheric ozone loss — take place over in the last 40 years. Below-average spikes in the size of the ozone hole were also recorded in 1988 and 2002.

The stratosphere’s ozone layer helps deflect ultraviolet (UV) radiation incoming from the sun. That’s very good news if you like being alive as UV rays are highly energetic and will cause harm to the DNA of living organisms. UV exposure can lead to skin cancer or cataracts for animals and damages plantlife.

A host of chemicals that used to be employed for refrigeration, including chlorofluorocarbons (CFCs) and hydrofluorocarbons (HFCs), break down ozone molecules in the stratosphere — which exposes the surface to greater quantities of UV. These compounds can last for several decades in the atmosphere and are extremely damaging to ozone during that time, breaking it down in huge quantities.

Humanity bunched together to control the production and release of such chemicals under the Montreal Protocol of 1988, which has drastically reduced CFC emissions worldwide. The ozone layer has been steadily recovering since then, but there’s still a long way to go.

“It’s a rare event that we’re still trying to understand,” Susan Strahan, an atmospheric scientist at the NASA’s Goddard Space Flight Center in Maryland, said in a news release. “If the warming hadn’t happened, we’d likely be looking at a much more typical ozone hole.”

The reactions that break down ozone take place most effectively on the surface of high-flying clouds, but milder-than-average temperatures above Antarctica this year inhibited cloud formation and made them dissipate faster, NASA explains. Since there were fewer clouds to sustain these reactions, a considerable amount of ozone made it unscathed. In a divergence from the norm, NOAA reports that there were no areas above the frozen continent this year that completely lacked ozone.

Warming in the shape of “sudden stratospheric warming” events, were unusually strong this year, NOAA adds. Temperatures in September were 29˚F (16˚C) warmer than usual (at 12 mi/19 km altitude) on average, “which was the warmest in the 40-year historical record for September by a wide margin” according to NASA.

Warmer air weakened the Antarctic polar vortex, a current of high-speed air circling the South Pole that typically keeps the coldest air near or over the pole itself, which slowed significantly (from an average wind speed of 161 mph / 260 kmph to 67 mph / 107 kmph). The slowed-down vortex allowed air to sink lower in the stratosphere, where it warmed and inhibited cloud formation. It’s also likely that it allowed for ozone-rich air from other parts of the Southern Hemisphere to move in.

Clouds.

Climate change and ozone layer holes form feedback loop, reports international panel

The frays in our planet’s ozone layer are leading to changes in the planet’s climate and ecosystem, new research shows.

Clouds.

Image via Pixabay.

Increased solar radiation levels, a consequence of damage to the ozone layer, are causing shifts in the climate which impact the Earth’s natural systems. These changes affect everything from weather to the health and distribution of sea life according to the study’s authors, members of the United Nations Environment Programme’s Environmental Effects Assessment Panel, which informs parties to the Montreal Protocol.

No-ozone zone

“What we’re seeing is that ozone changes have shifted temperature and precipitation patterns in the southern hemisphere, and that’s altering where the algae in the ocean are, which is altering where the fish are, and where the walruses and seals are, so we’re seeing many changes in the food web,” said Kevin Rose, a researcher at Rensselaer Polytechnic Institute who serves on the panel and is a co-author of the review article.

The 1987 Montreal Protocol on Substances that Deplete the Ozone Layer, often shorthanded as the ‘Montreal Protocol’, was the first ever multilateral environmental agreement ratified by all members of the United Nations. Its aim was to protect Earth’s ozone layer (which acts like a kind of planetary sunscreen, blocking UV radiation) by phasing out harmful handmade substances, most notably the chlorofluorocarbons class of refrigerants. All in all, the Protocol was a success, and total mean ozone levels are on track to recover to pre-1980s levels by the middle of this century.

Earlier this year, however, researchers reported detecting new emissions of ozone-depleting substances from East Asia, which could throw a wrench into the plan.

The link between ozone depletion and an increase in UV levels on the Earth’s surface is well known and well documented. However, the effect it has on climate isn’t. In fact, we’ve only recently wisened up to the fact that climate is also affected by ozone depletion. The current paper focuses on the Southern Hemisphere, where a hole in the ozone layer is currently centered around Antarctica.

The increased levels of UV radiation passing through this area have pushed the Antarctic Oscillation — the north-south movement of a wind belt that circles the Southern Hemisphere — further south than it has been in roughly a thousand years, the team reports. This shift is directly fueling climatic changes in the Southern Hemisphere, they add.

In effect, the hole is causing climate zones to shift southward, affecting rainfall patterns, sea-surface temperatures, and ocean currents across large areas of the southern hemisphere. For example, some areas of the oceans have become cooler and more productive, while others have warmed up and lost productivity.

These changes domino into terrestrial and aquatic ecosystems from Australia, New Zealand, Antarctica, South America, Africa, and the Southern Ocean. Warmer oceans are linked to declines in Tasmanian kelp beds and Brazilian coral reefs, and the ecosystems that rely on them. Cooler areas have helped some populations of penguins, seabirds, and seals, who now have more krill and fish to feed on.

Rose also points out to feedback loops linking climate to UV radiation. Higher concentrations of atmospheric CO2, for example, have increased overall ocean acidity. Acid attacks calcium carbonate, the main component of shellfish shells, which renders these animals more vulnerable to UV radiation. Even us, he adds, are likely to wear lighter clothes in the warmer atmosphere we’re creating, making ourselves more susceptible to damaging UV rays. Furthermore, the team found evidence that climate change is also impacting the ozone layer and its recovery.

“Greenhouse gas emissions trap more heat in the lower atmosphere which leads to a cooling of the upper atmosphere. Those colder temperatures in the upper atmosphere are slowing the recovery of the ozone layer,” Rose said.

As one of three scientific panels to support the Montreal Protocol, the Environmental Effects Assessment Panel focused in particular on the effects of UV radiation, climate change, and ozone depletion. Thirty-nine researchers contributed to the article. Rose, an aquatic ecologist, collaborated with the aquatic ecosystems working group, which is one of seven working groups that are part of the panel.

The paper “Ozone depletion, ultraviolet radiation, climate change and prospects for a sustainable future” has been published in the journal Nature Sustainability.

Atmospheric readings show someone is producing illegal, ozone-depleting industrial gases

Atmospheric readings show that someone, somewhere, isn’t playing by the rules.

Aerosol.

Aerosol used to widely incorporate these dangerous chemicals.
Image credits PiccoloNamek / Wikimedia.

Just last November, I’ve had the pleasure to report that, according to NASA’s measurements, 30 years of international effort and cooperation were doing the ozone layer some good. It was, all in all, very good news: it showed states could successfully and sensibly work together on ecological problems, and it meant we won’t get fried by solar radiation — both wins in my book.

However, a new study shows that not all is as well as we thought: someone has been cheating on the Montreal Protocol by producing new ozone-depleting chemicals on an industrial scale.

The ozone hole, renewed?

The Montreal Protocol of 1987 banned the production of three main ozone-destroying classes of chemicals: chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs). Since these compounds take an impressively long time to break down in the atmosphere, monitoring systems were set in place to make sure everything went smoothly. And good thing they did.

A team of researchers led by Stephen Montzka of the US National Oceanic and Atmospheric Administration (NOAA) reports that something is off with CFC-11 levels in the atmosphere. This chemical — previously used as a solvent, a refrigerant, as a precursor in styrofoam production, and a propellant in spray cans — is currently banned for production under the protocol. We used to employ a lot of it, however, and there are still sources of this gas leaking into the atmosphere (such as old refrigerators in landfills). However, these secondary sources should gradually decline, then disappear completely. As they do, we should see the decline of CFC-11 levels in the atmosphere accelerate.

But we aren’t. CFC-11 levels dropped some 2.1 ppt (parts-per-trillion) each year between 2002 and 2012. Afterward, however, the decline actually started to slow down: between 2015 and 2017, CFC-11 levels in the atmosphere dropped by only 1.0 ppt per year.

The concentration of CFC-11 in the Northern (red) and Southern (blue) Hemispheres compared to projected decline (gray lines).
Image credits Montzaka et al. (2018), Nature.

First, the team checked whether the change could come from natural processes. Some of these, however, could be ruled out quite easily: the first was whether weather-pattern-induced movements of CFCs in the stratosphere caused the observed variations. Another possible explanation, that a lot of old buildings using CFC-11-based ventilation systems were demolished at the same time, was also ruled out, as it didn’t plausibly fit the data, according to the team.

The team used atmospheric modeling to analyze what effect could lead to the observed rise. The concentration of these gases has always been higher in the (more developed, more industrialized) Northern Hemisphere than in the Southern one. Over the last few years, the team reports, this discrepancy between the two hemispheres has become more pronounced. Other gases haven’t followed the same pattern, the authors add, suggesting that the increase in CFC-11 emissions come from somewhere in the Northern Hemisphere.

Measurements taken at the Mauna Loa observatory in Hawaii also show that CFC-11 isn’t the only anthropic pollutant that’s seeing an uptick roughly since the year 2000. The team’s models showed that natural variability in atmospheric circulation (aka weather patterns) could only explain half of the observed increase — meaning that the only plausible explanation is an increase in emissions.

The team report that the source is most likely somewhere in Eastern Asia. They also estimate that around 6,500 to 13,000 tons of new CFC emissions would fit the observed trend in atmospheric concentrations.

“This is the first time that emissions of one of the three most abundant, long-lived CFCs have increased for a sustained period since production controls took effect in the late 1980s,” the researchers write.

“A delay in ozone recovery […] is anticipated, with an overall importance depending on the trajectory of CFC-11 emissions and concentrations in the future.”

The emissions are a direct violation of the Montreal Protocol. Signatories have taken it upon themselves to monitor CFC production and report it back to the United Nation group which oversees the protocol’s implementation. Against this backdrop, the team was very careful to spell out that they don’t have enough data to point towards a specific nation. They also add that its possible such production is taking place beyond the local government’s back — putting the ball in their court to safeguard the ozone layer.

The paper “An unexpected and persistent increase in global emissions of ozone-depleting CFC-11” has been published in the journal Nature.

Meet your new organ: the interstitium

Doctors have identified a previously unknown feature of human anatomy with many implications for the functions of most organs and tissues, and for the mechanisms of most major diseases.

Structural evaluation of the interstitial space. (A) Transmission electron microscopy shows collagen bundles (asterisks) that are composed of well-organized collagen fibrils. Some collagen bundles have a single flat cell along one side (arrowheads). Scale bar, 1 μm. (B) Higher magnification shows that cells (arrowhead) lack features of endothelium or other types of cells and have no basement membrane. Scale bar, 1 μm. (C) Second harmonics generation imaging shows that the bundles are fibrillar collagen (dark blue). Cyan-colored fibers are from autofluorescence and are likely elastin, as shown by similar autofluorescence in the elastic lamina of a nearby artery (inset) (40×). (D) Elastic van Gieson stain shows elastin fibers (black) running along collagen bundles (pink) (40×).

A new paper published on March 27th in Scientific Reports, shows that layers of the body long thought to be dense, connective tissues — below the skin’s surface, lining the digestive tract, lungs, and urinary systems, and surrounding arteries, veins, and the fascia between muscles — are instead interconnected, fluid-filled spaces.

Scientists named this layer the interstitium — a network of strong (collagen) and flexible (elastin) connective tissue fibers filled with fluids, that acts like a shock absorber to keep tissues from rupturing while organs, muscles, and vessels constantly pump and squeeze throughout the day.

This fluid layer that surrounds most organs may explain why cancer spreads so easily. Scientists think this fluid is the source of lymph, the highway of the immune system.

In addition, cells that reside in the interstitium and collagen bundles they line, change with age and may contribute to the wrinkling of skin, the stiffening of limbs, and the progression of fibrotic, sclerotic and inflammatory diseases.

Scientists have long known that more than half the fluid in the body resides within cells, and about a seventh inside the heart, blood vessels, lymph nodes, and lymph vessels. The remaining fluid is “interstitial,” and the current paper is the first to define the interstitium as an organ in its own right and, the authors write, one of the largest of the body, the authors write.

A team of pathologists from NYU School of Medicine thinks that no one saw these spaces before because of the medical field’s dependence on the examination of fixed tissue on microscope slides. Doctors examine the tissue after treating it with chemicals, slicing it thinly, and dyeing it in various colorations. The “fixing” process allows doctors to observe vivid details of cells and structures but drains away all fluid. The team found that the removal of fluid as slides are made makes the connective protein meshwork surrounding once fluid-filled compartments to collapse and appear denser.

“This fixation artifact of collapse has made a fluid-filled tissue type throughout the body appear solid in biopsy slides for decades, and our results correct for this to expand the anatomy of most tissues,” says co-senior author Neil Theise, MD, professor in the Department of Pathology at NYU Langone Health. “This finding has potential to drive dramatic advances in medicine, including the possibility that the direct sampling of interstitial fluid may become a powerful diagnostic tool.”

Researchers discovered the interstitium by using a novel medical technology — Probe-based confocal laser endomicroscopy. This new technology combines the benefits of endoscopy with the ones of lasers. The laser lights up the tissues, sensors analyze the reflected fluorescent patterns, offering a microscopic real-time view of the living tissues.

When probing a patient’s bile duct for cancer spread, endoscopists and study co-authors Dr. David Carr-Locke and Dr. Petros Benias observed something peculiar — a series of interconnected spaces in the submucosa level that was never described in the medical literature.

Baffled by their findings, they asked Dr. Neil Theise, professor in the Department of Pathology at NYU Langone Health and co-author of the paper for help in resolving the mystery. When Theise made biopsy slides out of the same tissue, the reticular pattern found by endomicroscopy vanished. The pathology team would later discover that the spaces seen in biopsy slides, traditionally dismissed as tears in the tissue, were instead the remnants of collapsed, previously fluid-filled, compartments.

Researchers collected tissues samples of bile ducts from 12 cancer patients during surgery. Before the pancreas and the bile duct were removed, patients underwent confocal microscopy for live tissue imaging. After recognizing this new space in images of bile ducts, the team was able to quickly spot it throughout the body.

Theise believes that the protein bundles seen in the space are likely to generate electrical current as they bend with the movements of organs and muscles, and may play a role in techniques like acupuncture.

Another scientist involved in the study was first author Rebecca Wells of the Perelman School of Medicine at the University of Pennsylvania, who determined that the skeleton in the newfound structure was comprised of collagen and elastin bundles.

Still hot inside the Moon? Earth gravity creating a hot layer

A new study has shown that there is still an extremely hot layer deep inside the moon, with heat generated by the gravity from the Earth. If this is indeed the case, then the inside of the Moon has not yet entirely solidified, providing an insight on to how the Earth-Moon system evolved.

Credit: Image courtesy of National Astronomical Observatory of Japan

There is still a lot of debate regarding the Moon’s nature – is it a true satellite, or is it in fact a planet of its own, trapped by the Earth’s gravity system? When discussing the nature of such a celestial planet, you must understand how it was born and how it evolved. But studying the early stages and evolution of the Moon is no easy feat, and that’s why researchers were thrilled to find this hot layer. But how do you “find” a hot layer in the depths of the Moon? The key here is gravity.

We can get a good indication of what’s happening inside a celestial body by studying slight modifications in its shape. The shape of a celestial body being changes by the gravitational force of another body is called tide; we see this on Earth, in the oceans. High and low tides occur mostly due to the Moon’s gravity (the Sun also plays a smaller role), because water is so deformable that its desplacement can be easily observed. But even the solid parts can be displaced, though to a much smaller extent. Observing the degree of deformation enables us to infer several things about the interior.

But there are more ways to study the internal structure. When the Apollo program landed people on the Moon, they also left seismological sensors on the surface – because the Moon also has earthquakes (perhaps moonquakes would be more accurate though). Through these sensors, they showed that the satellite has two main parts: the “core,” the inner portion made up of metal, and the “mantle,” the outer portion made up of rock. Based on this data, and previous shape deformation observations, Dr. Yuji Harada and his team managed to show that there is also an intermediate, hot layer, wrapping and warming the core. But this study, while it may very well revolutionize what we know about the moon, it actually poses more questions than it answers, researchers say:

“I believe that our research results have brought about new questions. For example, how can the bottom of the lunar mantle maintain its softer state for a long time? To answer this question, we would like to further investigate the internal structure and heat-generating mechanism inside the Moon in detail. In addition, another question has come up: how has the conversion from the tidal energy to the heat energy in the soft layer affected the motion of the Moon relative to the Earth, and also the cooling of the Moon? We would like to resolve those problems as well so that we can thoroughly understand how the Moon was born and has evolved.”

Another investigator, Prof. Junichi Haruyama of Institute of Space and Aeronautical Science, Japan Aerospace Exploration Agency also emphasizes the significance of this study:

“A smaller celestial body like the Moon cools faster than a larger one like the Earth does. In fact, we had thought that volcanic activities on the Moon had already come to a halt. Therefore, the Moon had been believed to be cool and hard, even in its deeper parts. However, this research tells us that the Moon has not yet cooled and hardened, but is still warm. It even implies that we have to reconsider the question as follows: How have the Earth and the Moon influenced each other since their births? That means this research not only shows us the actual state of the deep interior of the Moon, but also gives us a clue for learning about the history of the system including both the Earth and the Moon.”

Scientific Reference: Yuji Harada, Sander Goossens, Koji Matsumoto, Jianguo Yan, Jinsong Ping, Hirotomo Noda, Junichi Haruyama. Strong tidal heating in an ultralow-viscosity zone at the core–mantle boundary of the Moon. Nature Geoscience, 2014; 7 (8): 569 DOI: 10.1038/ngeo2211