Expedition zu den antarktischen Seen auf dem Amery Eisschelf

Leserpost von Susanne Klug:

Uns macht akut die zunehmende Schallbelastung bei Tieffrequenzen und Infraschall und deren gesundheitlichen Auswirkungen zu schaffen. Diese müssten dringend geklärt und diskutiert werden. Es sind nicht nur Erneuerbare Energien-Anlagen ursächlich, aber zu einem großen Teil, der ja noch massiv zuwachsen soll. Wir haben eine Petition zum Thema beim Bundestag eingereicht, weil die mittlerweile großflächige Schallbelastung aus unserer Sicht nicht mehr nur regional zu lösen ist. Die Petition ist aktuell veröffentlicht zur Mitzeichnung und Diskussion bis zum 09.08.2022.

Hier der Petitionstext und die Begründung:

Mit der Petition werden Maßnahmen gegen tieffrequenten Schall und Infraschall gefordert.

Begründung: Immer mehr Menschen in Deutschland sind von einer Belastung durch tieffrequenten Schall bzw. Infraschall von technischen Anlagen betroffen. Eine andauernde Belastung durch diesen Schall kann schwerwiegende Auswirkungen auf die Gesundheit haben, das bestätigen auch Fachpublikationen; dennoch werden keine wirksamen Maßnahmen seitens der Umwelt- und Gesundheitsbehörden getroffen. Die Auswirkungen könnten auch die Menschen betreffen, die den Schall nicht bewusst wahrnehmen. Hinweise darauf gibt es von Fachleuten, weitere Untersuchungen jedoch nicht.

Aufgrund der Tatsache, dass bei Tieffrequenzen und Infraschall in den meisten Fällen mit vertretbarem wirtschaftlichem Aufwand Schallminderung an den verursachenden Schallquellen erreicht werden könnte, besteht dringend Handlungsbedarf zur Klärung und Besserung der Situation. Nach dem Motto zu verfahren: „Solange die Mehrheit sich nicht beschwert, machen wir weiter so“, ist aus unserer Sicht eine schwerwiegende Unterschätzung der Lage.

Hier kann die Petition gezeichnet werden.

Bericht zur Petition auf Ruhrkultur.

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Der bekannte Klimarealist Patrick Michaels verstarb jetzt mit 72 Jahren.

Hier ein Vortrag von Pat Michael:

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Pennsylvania State University:

Strong tides, vanishing lakes may prove beneficial to Antarctic ice shelf

The lakes that form on Antarctica’s ice shelves can drive vertical cracks deep within the ice, increasing the chance of ice shelf collapse and sea level rise. However, if meltwater accumulates in certain areas and drains fast enough, it may temporarily stabilize the ice shelf despite increased warming, according to researchers.

„Antarctica’s ice is the largest potential source of sea level rise,“ said Luke Trusel, assistant professor of geography at Penn State. „A significant percentage of the global population lives along the coastline in many of the world’s largest cities. We need to understand what is happening to ice shelves to make reliable sea level predictions. Water can destabilize ice shelves, so we need to know where the water is and what it’s doing.“

Trusel and his colleagues used satellite data to study a meltwater lake that forms annually at the grounding line of the Amery Ice Shelf in East Antarctica. The grounding line is a zone where land ice transitions to a floating ice shelf that prevents the land ice from flowing into the ocean and raising sea levels. The ice in this area tends to dip and form a basin that could collect water.

The researchers found that strong tidal activity may facilitate water-induced fracturing, or hydrofracturing, at the grounding line and cause the meltwater lake to drain quickly, often in as little as several days. The rapid draining prevents more water from accumulating and spreading onto the ice shelf, where hydrofracturing would raise the potential for collapse. The team reported their findings, which are the first observations of tides potentially forcing large-scale lake drainage, in Geophysical Research Letters.

The researchers used data from the Landsat 8 and Sentinel-1 satellites to measure and track changes to the lake during the austral summers—December through February—of 2014 to 2020. Whereas an ordinary camera captures three different wavelengths—red, green and blue—to create an image, the Landsat 8 instruments can capture up to 11 spectral bands, including infrared light. The data return as pixels that can be used to map ice, water, snow and cloud cover.

Zhuolai Pan, a master’s student in geography at Penn State who started on the project as an undergraduate, used the Landsat images to calculate lake volume and create a time series that shows the lake forming and draining. To refine the time series, the team used data from the radar imaging sensors on twin Sentinel-1 satellites. The instruments have a resolution of approximately 33 feet and can see through cloud cover, which is important because Antarctica’s coasts can often see more clouds than sun.

The lake is approximately 2.3 square miles and 65 feet deep and contains almost 5 billion gallons of water, enough water to fill nearly 7,200 Olympic-sized swimming pools, according to the researchers.

„It’s not the biggest lake, but it’s appreciable in terms of its size,“ Trusel said. „The more interesting aspect is the dynamics, how the water is changing so quickly and what that may mean for our understanding of ice shelf stability. A large volume of water is just disappearing, and it’s doing this almost every year.“

The researchers also examined high resolution satellite imagery taken after a drainage event. The images showed the lake bottom, where the team found a 26-foot-deep and 800-foot-wide crater, ice blocks that would have fit inside the crater and a more than 2,100-foot-long fracture. These details indicate that the water most likely drained vertically, roughly 2,000 feet through the ice.

„This is the most detailed view of a freshly drained lake in Antarctica we’ve ever had,“ said Trusel, noting that the features they spotted had only previously been observed on the much warmer and wetter Greenland Ice Sheet.

Drainage events occurred at least once a year for all years with sufficient observations and at different lake volumes. Given that drainage seemed to occur at different lake volumes and depths, as well as around the new and full moon, the researchers think that strong tidal activity, instead of water volume, was the driving force.

Earth experiences stronger tidal activity when the Earth, moon and sun align, Trusel said. Because they float in the ocean, ice shelves are subject to tidal activity. Higher high tides force the ice shelf to flex up and generate stresses at the base of the ice that could cause a fracture. Lower low tides force the ice shelf to flex downward, transferring those stresses to the surface of the ice and potentially extending the fracture. The weight of the water at the surface could cause the fracture to propagate through the ice shelf until an opening forms and drains the lake.

„The tides flex the ice shelf at the grounding line,“ said Trusel. „The ice is acting like a door hinge, with stresses occurring at the top and bottom of the ice right where this lake exists.“

Scientists have thought that water at the surface is a precursor for ice shelf collapse. They observed the phenomenon when the Larsen B Ice Shelf collapsed in 2002. Earlier Landsat data, however, shows the lake in the current study forming as far back as the 1970s, said Pan. Many of the same lakes that dot the ice shelf today also appear in aerial photographs taken by the U.S. Navy shortly after World War II.

„Revisiting observations from older aerial imagery and satellite data, we see that much of this water has been around for some time, and so there’s more nuance here,“ Trusel said. „Water and ice can in some instances coexist. There’s more we need to know about how exactly it impacts ice shelf stability.“

The scientists‘ next step is to investigate whether other lakes in the region drain as a result of tidal activity. The current study raises many questions, Trusel said, but it represents the latest step to better understanding ice shelf stability and how fast seas will rise in the future.

Mahsa Moussavi, a formal postdoctoral researcher at the National Snow and Ice Data Center and now at General Motors, also contributed to the study.

Paper: Luke D. Trusel et al, Repeated Tidally Induced Hydrofracture of a Supraglacial Lake at the Amery Ice Shelf Grounding Zone, Geophysical Research Letters (2022). DOI: 10.1029/2021GL095661

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In den Niederlanden protestieren die Landwirte gegen klimawandelmotivierte Eingriffe in ihre Betriebe. Die deutschen Medien schweigen. Zu groß die Gefahr, dass auch hier die Landwirte auf die Barrikaden gehen könnten. Hier die Pläne der EU zu den Methaneinschränkungen.

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Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB):

Phytoplankton bildet Methan

Lange gingen Forschende davon aus, dass Methan in Binnengewässern nur dort gebildet wird, wo kein Sauerstoff vorhanden ist – in Seensedimenten, Feuchtgebieten und Sümpfen. Jüngste Studien zeigen, dass dieses Treibhausgas auch in der sauerstoffreichen Wassersäule entsteht: Verschiedene Phytoplankton-Arten – Cyanobakterien, Kieselalgen und Haptophyten – emittieren Methan während ihrer Photosynthese. Die IGB-Forscherin Dr. Mina Bizic hat das Wissen zur Methanbildung durch Phytoplankton gebündelt und die möglichen Folgen diskutiert.

Weiterlesen

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Kennen Sie schon den Youtube-Kanal „Energie Info“? Hier geht’s zur Übersicht der Video-Clips.

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New Atlas:

Cheap, common kitty litter clay captures methane from the air

Carbon dioxide may hog the headlines as a climate change villain, but methane is actually a far more potent greenhouse gas. An MIT team has now demonstrated a new way to remove methane from the air, even at very low concentrations, with a common type of clay used to make cat litter.

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The Conversation:

Methane in the atmosphere is at an all-time high. What it means for climate change

Methane recently reached 1,900 parts per billion (ppb) of Earth’s atmosphere according to measurements taken by the National Oceanic and Atmospheric Administration (NOAA) in the US. This compares with about 700 ppb before the industrial revolution.

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Scinexx:

Mikrobe erzeugt Strom aus Methan

Direkte Elektronenfreisetzung könnte Biogasnutzung effizienter machen

Lebender Stromproduzent: Forscher haben eine Mikrobe entdeckt, die aus Methan Strom erzeugen kann. Die in Seen und Gräben vorkommende Archaee setzt beim biochemischen Umbau des Methans zu Kohlendioxid Elektronen frei, die als Strom abgeleitet werden können. In ersten Tests lag der Wirkungsgrad dieser biochemischen Stromerzeugung zwar nur bei 17 Prozent, dürfte aber steigerbar sein, so das Team. Die „Methanfresser“-Mikrobe könnte damit neue Möglichkeiten der Stromgewinnung aus Biogas eröffnen.

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