GLOBAL WARMING IN ANTARCTICA
GLOBAL WARMING IS DEVASTATING ANTARCTICA
WORLD RESOURCE INSTITUTE (WRI.ORG): APRIL 10, 2020: [LINK]
The Antarctica that we know is being transformed by human caused global warming and climate change. The rate of ice loss from Antarctica has tripled since 2012 compared to ice losses from the previous two decades. Large enough chunks of ice are calving off of the Antarctic ice shelves that maps must be redrawn. Just this past summer, over the period from November to February, scientists documented unprecedented heatwaves and melting at Casey Station, East Antarctica. These sorts of impacts are expected to continue as warming continues and will be felt far beyond the continent. The breakup of the Antarctic ice sheet fuels sea level rise, affecting communities around the world, while recent research revealed the connection between Antarctic ice, ocean circulation patterns and the risk of more frequent extreme events.
1. Antarctica’s air and ocean are heating up: The Antarctic Peninsula is witnessing some of the most rapid warming on Earth. In the last 50 years, the peninsula warmed at a rate of 0.06C per year, significantly higher than the global average. In February, Argentina’s Esperanza research station recorded high temperatures of 18.3C , the highest temperature ever recorded in continental Antarctica. Higher temperatures are resulting in ice loss and warmer waters surrounding the continent. The oceans around Antarctica are getting hotter as well, with some areas of the Southern Ocean warming by 3C. This is particularly problematic, because ice loss has been greatest where there’s an influx of warm waters. Researchers now warn that there could be more ice shelves exposed to warm waters than previously thought, especially in East Antarctica, which could contribute multi-meter sea level rise if climate change continues unabated.
2. Ice is retreating and melting rapidly. The rate of ice loss from Antarctica has tripled since 2012 compared to ice losses from the previous two decades. Large enough chunks of ice are calving off the Antarctic ice shelves that maps are needing to be redrawn. The world’s largest iceberg “A68” – weighing 1.1 trillion tons and the size of Delaware – broke off from the Larsen C ice shelf in July 2017. Ice loss from the Antarctic Ice Sheet has rapidly accelerated over the last four decades. These types of calving events are becoming increasingly frequent. Just last month, an iceberg twice the size of Washington, D.C. broke off the rapidly retreating Pine Island Glacier. Fracturing of the ice shelf is a sign of its weakness; thinning and breakup of the ice can further destabilize the ice shelf. In the nearby Thwaites Glacier, researchers recently found a large underwater cavity, two-thirds the size of Manhattan. The cavity used to contain 14 billion tons of ice, but much of it has melted in just three years. The presence of a cavity like this allows for warm waters to get further under the glacier, allowing it to melt faster. Warming is resulting in ice loss, including melting underneath glaciers. These discoveries come against a backdrop of longer-term trends. Using satellite record data, scientists estimated that ice mass loss from the Antarctic Ice Sheet has accelerated over the last four decades, increasing six-fold from roughly 40 billion tons per year in 1979–1990 to about 252 billion tons a year in 2009–2017. Those figures mask changes in particularly vulnerable areas. For example, scientists recently found that a part of the Ross Ice Shelf that is particularly important for its overall stability is melting 10 times faster than the shelf average. Scientists also found that surface meltwater is now widespread across the Antarctic Ice Sheet, leading to rapid and large accelerations of outlet glaciers, a glacier that flows out of an ice sheet and can drain it quickly. Such shifts have not been included in models to date. And in addition to meltwater, lakes are sitting on the surface of East Antarctica, reducing surface reflectivity of the ice and increasing absorption of solar radiation, which speeds up melting. Scientists also recently reported large lakes under eastern Antarctica. It’s a troubling finding, as glaciers can move more quickly when they sit on water as opposed to bedrock.
3. Penguin populations are shrinking. Some penguin species are adapting to warmer temperatures, while other populations are declining. On certain islands off the coast of the Antarctic peninsula, thousands of penguins, black and white, stretched up the hillside. On others, however, isolated groups of penguins sat next to empty sites that were once full of life. Naturalists told us how several colonies they frequented dropped dramatically in recent years. As krill populations decline, some penguins are relying on new penguins sources, including fish and squid. Climate change is creating penguin winners and losers. Their fate hinges on how dependent they are on krill, which has declined by 70-80% in some regions of the Weddell Sea and waters off of the Antarctic peninsula, as a result of commercial fishing, sea ice loss and recovery of whales. Gentoo penguins, on the one hand, have diversified their diet to include fish and squid. They’ve seen greater success than the Chinstrap and Adélie penguins, which almost exclusively rely on krill. For example, in the South Shetland Islands off the western Antarctic Peninsula, Adélie breeding pairs dropped from 105,000 to 30,000 from 1982 to 2017. Over the same period, breeding pairs of Gentoos climbed from 25,000 to 173,000. A preliminary census released in February 2020 found that some chinstrap colonies have seen as much as a 77% decline since the 1970s.
4. SNOW IS TURNING RED. When I pictured Antarctica, I envisioned cool shades of blue and white. But there I was with my rubber boots digging into snow that looked like it had been spray-painted red. Rising temperatures are allowing algae to grow in large masses, giving snow a red pigment. This phenomenon is not new, with reports of red snow as old as millennia, dubbed “watermelon snow.” It’s a result of algae living on the snow, which produce a reddish pigment to protect from solar radiation during warmer seasons. The problem is that in a changing climate, this can lead to a “feedback loop” that exacerbates warming. As temperatures warm, the algae are able to grow in greater masses, turning the snow a darker shade. This reduces surface reflectivity and, in turn, causes more solar radiation absorption, furthering melt. A recent study of 40 red snow sites across the Arctic confirmed higher melt rates when the algae was present.
5. LAND IS TURNING GREEN: In addition to seeing pink snowfields, I never imagined Antarctica to be quite as green as it was, with its mosses, lichens and flowering plants. I never thought I’d see a penguin waddle amongst green grass, almost appearing photoshopped against a background thousands of miles away. Once snowy hills are now covered in more vegetation as increased temperatures release nitrogen from the underlying soil. Antarctica has two vascular plants – Antarctic hair grass (Deschampsia antarctica) and Antarctic pearlwort (Colobanthus quitensis). A recent study documented the proliferation of these two native plants, especially the hair grass, thanks to newly available nitrogen. Nitrogen is typically locked away in soil that is now decomposing more quickly as temperatures increase. What Happens in Antarctica Doesn’t Stay in Antarctica. No area on our planet is spared from warming—nor does warming in one area stay confined to that region. Though Antarctica seems so far away, human activities occurring on continents separated by vast seas are affecting its lands, waters and the life that exists there. And, by the same token, climate impacts to Antarctica won’t be a localized phenomenon; they will affect the entire planet, with rising seas flooding low-lying communities around the world, altered ocean circulation patterns, and potentially more frequent extreme weather events. Additionally, Antarctica may be a predictor of patterns of change that the rest of the world may see in the future. The impacts of climate change are already painted across the landscape of Antarctica. Effective and immediate action against climate change is crucial to preventing future impacts that will transform not only Antarctica, but the world at large. THE END.
OR MAYBE IT’S JUST INTERNAL CLIMATE VARIABILITY
CHANGES IN IN ANTARCTICA IN THE LAST 30 YEARS IS INTERNAL CLIMATE VARIABILITY NOT GLOBAL WARMING.
Clem, K.R., Fogt, R.L., Turner, J. et al. Record warming at the South Pole during the past three decades. Nat. Clim. Chang. (2020). https://doi.org/10.1038/s41558-020-0815-z
ABSTRACT
Over the last three decades, the South Pole has experienced a record-high statistically significant warming of 0.61 ± 0.34 °C per decade, more than three times the global average. Here, we use an ensemble of climate model experiments to show this recent warming lies within the upper bounds of the simulated range of natural variability. The warming resulted from a strong cyclonic anomaly in the Weddell Sea caused by increasing sea surface temperatures in the western tropical Pacific. This circulation, coupled with a positive polarity of the Southern Annular Mode, advected warm and moist air from the South Atlantic into the Antarctic interior. These results underscore the intimate linkage of interior Antarctic climate to tropical variability. Further, this study shows that atmospheric internal variability can induce extreme regional climate change over the Antarctic interior, which has masked any anthropogenic warming signal there during the twenty-first century.https://video.wordpress.com/embed/kM7fYKNo?hd=0&autoPlay=0&permalink=0&loop=0
— Thongchai Thailand
