[LINK TO THE HOME PAGE OF THIS SITE]

RELATED POSTS ON ANTARCTICA

[LINK] [LINK] [LINK] [LINK] [LINK] [LINK][LINK] [LINK] 

THIS POST IS A CRITICAL REVIEW OF THE YOUTUBE LECTURE BY TBGY [LINK] ON THE URGENT NEED FOR A DECISIVE & COMPREHENSIVE CLIMATE ACTION PLAN AT COP26 IN GLASGOW TO MOVE THE GLOBAL ENERGY INFRASTRUCTURE AWAY FROM FOSSIL FUELS AND THUS HALT FOSSIL FUEL DRIVEN AGW CLIMATE CHANGE THAT WOULD OTHERWISE CAUSE CATASTROPHIC SEA LEVEL RISE BY MELTING THE THWAITES GLACIER IN WEST ANTARCTICA.

IT IS PRESENTED IN THREE PARTS. PART-1 IS A TRANSCRIPT OF THE LECTURE. PART-2 IS A CRITICAL COMMENTARY. PART-3 IS A RELEVANT BIBLIOGRAPHY. 

PART-1: TRANSCRIPT OF THE LECTURE

1. Antarctica is so remote and extreme that it remains one of the last remaining regions of our planet we humans haven’t yet colonized. Snow storms with wind speeds of up to 200 mph and year-round temperatures as low as -80C and rarely above 0C make it so inhospitable that no human could stay there on any kind of permanent basis. The only visitors are these scientists who pitch up in the summer months to carry out their research. Antarctica is big. It is 30% bigger than Europe. This continent sized ice sheet is the biggest ice sheet on earth. It is about a mile thick on average and it contains more than 70% of all the fresh water that’s available on the planet.
2. But researchers have been discovering that the climate in Antarctica is changing fast, much faster than the rest of the planet and faster even than previous model predictions. The proof of that is that on the 9th of February 2020, an air temperature of almost 21C was logged at Seymour Island over on the West Antarctic Peninsula. That is 4C warmer than the previous record of 19.8C in 1982; and it is consistent with the broader average trend of the Antarctic Peninsula of about 3C of warming since pre-industrial. A couple of thousand miles from Seymour Island, over in East Antarctica, the ice sheet sits high up on solid bedrock and barely moves at all. This stuff has been around for millions of years. But back over on West Antarctic, close to where those record air temperatures were recorded, the ice perches much more precariously on top of a series of islands that dip well below sea level. And it is in the remotest part of this icy wilderness that we find some of the world’s largest glaciers including the Thwaites Glacier, now being referred to by some glaciologists as The Doomsday Glacier. Why “The Doomsday Glacier”? Well, scientific researchers have known for some time that the melt rate of Thwaites is responsible for 4% of global sea level rise. And they also know that the warming climate is increasing the rate at which surface melting is occurring on the Thwaites glacier.
3. There is another factor at play here. Around the same that the record temperatures were recorded on Seymour Island, A group of researchers from the UK and the US, on a significant long term research program called the Thwaites Glacier Collaboration (TGC) launched a temperature probe called ice fin 600 meters down to the bottom of the glacier to the point where it meets the ocean water. What that probe has now confirmed, is that unlike the waters at the surface which are at -2C at the cusp of the freezing point of sea water, the temperature of the ocean water now washing against the base of the glacier is +2C, above freezing. And that’s a pretty good temperature for melting ice.
4. So what’s been causing such dramatic increases in air and water temperatures? And how much faster is Thwaites Glacier melting as a result? And what happens if the whole thing lets go?
5. Here are a few fun facts about Thwaites Glacier just to get it warmed up. #1: It’s one of the biggest glaciers on the planet. It’s absolutely enormous. It is about the same size as Britain or the State of Florida. #2: I is very difficult to get to. It’s right on the very westernmost side of the least navigable part of the continent. It is more than a thousand miles to the nearest research station. And the intrepid scientists in the ??? division have setup a dedicated camp halfway down the length of the ??? just so the old propeller planes that carried them to the front edge could refuel before embarking on the last section of the flight. #3: Before the Thwaites Glacier Collaboration expedition got there, only four human beings had ever stood at the leading edge of the glacier. And those four people were the advance party for the expedition itself. #4: Thwaites Glacier sits like a giant plug at the front of the West Antarctic Ice Sheet potentially holding back the movement of even more glacial and land ice towards the ocean. #5: Satellite monitoring over the last couple of decades has shown that the rate of ice loss from the Thwaites Glacier has doubled.
6. First of all, what does, what do the scientific researchers tell us is causing the warming of the deep waters? Well, it may not surprise you to hear that there is a climate change influence at play here. The movements of currents around the planet is governed by a complex and interlinked system known as the Thermohaline Circulation, sometimes called the great ocean conveyor belt. A look at the detail of how that system works is in an earlier episode [LINK] . Essentially, the Gulf Stream takes warm water across the Atlantic and up toward the Arctic region where the warm salty dense tropical water meets the colder fresher Arctic water, it sinks and gets caught up in the deep water Atlantic current system that takes it all the way to the Antarctic where some of it forms the Antarctic Circumpolar Current system which is a relatively warm water circulating around the entire continent of Antarctica hundreds of meter deep beneath an extremely cold layer of water above. Eventually by other mechanisms that are ???? the flow of water makes its way back up north and joins up with the Gulf Stream again and this continuous circuit is completed. There’s nothing new here. That ocean circulation has been going on for eons.
7. What’s changed, according to the scientific researchers studying the effects that are going on down there is that a warming of the Pacific has shifted the wind pattern in the air streams above which in turn is changing flows of water and allowing the deep waters to come into contact much more with the continental shelf. The difference in temperature is only 2C or 3C, but like so many other aspects of climate change, because the scale is so vast, the effect can be very dramatic.
8. So what about that air temperature rise then? Well, according to this Guardian report, the scientists that collect the data say the rise in temperature appears to be driven by a rise in ocean currents as well as an increase in frequency and strength of El Nino events bringing warmer air further south towards regions where it previously wouldn’t have reached. The impacts vary across Antarctica but the Antarctic Peninsula, so far being the most dramatically affected, Carlos Schaefer, who monitors the impact of climate change on permafrost and biology of 23 sites on the Antarctic, pointed out that the monitoring data from these areas could indicate what’s in store for other parts of the region. He said, it’s important to have sentinel areas like the South Shetlands and the Antarctic Peninsula because they can anticipate the developments that will happen in the future, the near future.
9. In the case of Thwaites Glacier, which is about a hundred miles wide at its front edge, top sections of ice as big as two miles long can break off into the sea each year. The leading edges of the Antarctic glaciers build up over time and project forwards away from the land mass to create quite a precarious ice shelf. At their base, the glaciers attach to the land mass to the point the scientists call a grounding line. Under normal circumstances, erosion of the top and bottom cause bits of the glacier to shear off into the sea. Those icebergs freshen the surrounding water which drives deeper warmer water down pushing it toward the base of the glacier. That’s all part of the cycle of glacial renewal. It all happens extremely slowly and the volume of ice lost into the water is generally balanced out by the fresh new snowfall on the land building the glacial mass back up again. And so the cycle goes round and round more or less perpetually.
10. The data from this latest expedition, including the temperature readings taken by the Ice Fin probe, show a mast faster erosion rate at the base as a result of greater levels of warmer water reaching the all important grounding line.
11. According to Professor David Holland, one of the leading oceanographers on the Thwaites Glacier Collaboration expedition, that warmer water can increase melt rates by as much as a hundred fold. And as larger and larger sections drop of the front of the glacier as a consequence and leave behind thicker and thicker sections of shelf, gravity acts on these sections with the effect that they get pushed forward more quickly. So the more the glacier melts, say the scientific researchers, the faster the ice within the glacier is likely to flow out. And lo and behold we got ourselves another one of those pesky feedback loops that seem to be such a commonplace and prominent feature of our warming climate.
12. So is the Thwaites Glacier likely to collapse any time soon? Unlikely, according to glaciologists; but they do warn us that the melting is speeding up fast enough for much of it to disappear in the coming decades and perhaps be gone completely within a century. With enough fresh water locked up in the Thwaites Glacier alone to raise the global sea level by 50cm. Doesn’t sound like much does it? But over the entire surface of the planet’s seas and oceans, that’s a big increase.
13. Add to that the sea level rises we are already experiencing as a result of our warming atmosphere, and the level doubles to more like a meter. As well as the obvious effects on low lying coastal regions around the planet, these higher water levels will also vastly increase the regularity and severity of storms and storm surges.
14. The BBC’s Justin Rowlatt spent some time with the expedition down in Antarctica and he spoke with Professor David Vaughn, Director of the British Antarctic Survey about what the effects might look like. Vaughn suggested that an increase of 50cm in sea levels will mean that thousand-year-storms will be arriving every 100 years or so; but at a meter of sea level rise, those millennial storms are likely to arrive once a decade.
15. Rising sea levels are not thought to be on track to affect about three times more people by 2050 than originally thought. A paper from scientists at the European Commission’s Joint Research Center, suggests that 300 million homes will be affected by coastal flooding in the next 30 years and 630 million by the year 2100 if we remain in our current business as usual trajectory of greenhouse gas emissions.
16. Yet another reason, if we needed any more, why this year’s COP26 climate conference in Glasgow will require an absolutely unanimous commitment from every participating nation and as many States as possible from the United States of America to a collaborative program of radical emission reductions with a focus on the rapid move away from fossil fuels and into low or zero carbon forms of energy production coupled with vast new infrastructure projects building distributed smart grids and energy storage facilities across the planet. And alongside that, if we are to keep global temperature rise below 2C above pre-industrial, we will also need global scale re-forestation and land regeneration so we can start taking carbon back out of the atmosphere and locking it up in our natural ecosystem. If we achieve that, it will be the biggest coordinated global effort since the Second World War, and it will represent a generation’s worth of work with millions of new jobs being created as a result.

PART-2: CRITICAL COMMENTARY

1. About the high temperature events on the Antarctic Peninsula: AGW climate change is a theory about long term trends in global mean surface temperature. Localized and isolated temperature events have no interpretation in terms of AGW particularly so when they are more readily explained in terms of known natural phenomena such as Foehn winds and geothermal heat that are known to cause such events. Both of these phenomena of nature are found in West Antarctica and particularly so in the region of the Antarctic Peninsula where Seymour Island is located. Some details of these temperature phenomena and the remarkable absence of long term warming trends in the South Polar Region are described in these related posts [LINK] [LINK] [LINK] . Without further evidence, these extreme temperature events do not show that “the climate in Antarctica is changing fast, much faster than the rest of the planet”.
2. It is not true that the only visitors to Antarctica are scientists. The greater and more frequent number of visitors by far are tourists, mostly from South America. The South Shetland Island located in the Antarctic Peninsula is home to the Deception Island Collapse Caldera where the volcano there had erupted so violently that the center of it collapsed and became filled with sea water that is kept at a hot spring temperature by geothermal heat because that volcano is still active. This Deception Island Collapse Caldera draws a large number of tourists during the austral summer. The tourists like to soak in the steaming hot water of the collapse caldera. 
3. It is a reasonable hypothesis that the bottom of the Thwaites Glacier dips down into warm ocean water more than 600 meters below and that this contact with warm ocean water is the cause of the observed ice mass losses from the glacier. However, the real question here is the source of the energy that warms the deep ocean in an otherwise cold ocean on the surface and the surface layers. It may be argued that the source of this heat is the warm water of the tropics that is transferred to Antarctica by the Conveyor Belt ocean circulation system in a journey of more than 20,000 km that takes it from the Tropics to the North Atlantic where it sinks and then along the bottom of the ocean to the Antarctic where it discharges the heat from the tropics into the Circumpolar Deep Water Circulation (CDWC). However, in a highly geologically active area such as West Antarctica and the Antarctic Ocean, a role for geothermal heat cannot be ignored as recent research papers on the Circumpolar Deepwater Circulation have pointed to significant geothermal heat sources on the sea floor that offer a more ready explanation for the warmth of the CDWC as can be seen in the papers cited below.
4. The geological activity In West Antarctica and the Antarctic Ocean are described in a related post [LINK] where we see the important role of the West Antarctic Rift system and the Marie Byrd Mantle Plume in the interpretation ocean temperature and ice melt in this region. In particular, the ice melt in the Thwaites Glacier should be understood in terms of the active volcanoes underneath the glacier [LINK] .

SUMMARY

IN LIGHT OF SIGNIFICANT GEOLOGICAL FEATURES OF WEST ANTARCTICA AND THE ANTARCTIC OCEAN , THE USE OF AGW HEAT TRANSFERRED FROM THE TROPICS TO THE CIRCUMPOLAR DEEP WATER CIRCULATION OF THE ANTARCTIC OCEAN TO EXPLAIN ICE MELT PHENOMENA THERE IN TERMS OF AGW LIKELY DERIVES FROM AN EXTREME FORM OF THE ATMOSPHERE BIAS OF CLIMATE SCIENCE SUCH THAT OCEAN TEMPERATURE AND ICE MELT PHENOMENA IN A GEOLOGICALLY ACTIVE AREA WITH EXTENSIVE SOURCES OF GEOTHERMAL HEAT ARE INTERPRETED IN TERMS OF AGW DRIVEN BY FOSSIL FUEL EMISSIONS TO PROPOSE THAT THESE MELT PHENOMENA CAN BE MODERATED WITH CLIMATE ACTION AT THE COP26 MEETING TO ELIMINATE THE USE OF FOSSIL FUELS. 

BIBLIOGRAPHY

GEOTHERMAL WARMING OF CIRCUMPOLAR DEEP WATER CIRCULATION

1. Mashayek, A., et al. “The role of the geothermal heat flux in driving the abyssal ocean circulation.” Geophysical Research Letters 40.12 (2013): 3144-3149. [FULL TEXT]  The results presented in this paper demonstrate that the geothermal heat flux (GHF) from the solid Earth into the ocean plays a non‐negligible role in determining both abyssal stratification and circulation strength. Based upon an ocean data set, we show that the map of upward heat flux at the ocean floor is consistent (within a factor of 2) with the ocean floor age‐dependent map of GHF. The observed buoyancy flux above the ocean floor is consistent with previous suggestions that the GHF acts to erode the abyssal stratification and thereby enhances the strength of the abyssal circulation. Idealized numerical simulations are performed using a zonally averaged single‐basin model which enables us to address the GHF impact as a function of the depth dependence of diapycnal diffusivity. We show that ignoring this vertical variation leads to an under‐prediction of the influence of the GHF on the abyssal circulation. Independent of the diffusivity profile, introduction of the GHF in the model leads to steepening of the Southern Ocean isopycnals and to strengthening of the eddy‐induced circulation and the Antarctic bottom water cell. The enhanced circulation ventilates the GHF derived heating to shallow depths, primarily in the Southern Ocean.
2. Downes, Stephanie M., et al.  [LINK] “The transient response of southern ocean circulation to geothermal heating in a global climate model.” Journal of Climate 29.16 (2016): 5689-5708.  Model and observational studies have concluded that geothermal heating significantly alters the global overturning circulation and the properties of the widely distributed Antarctic Bottom Water. Here two distinct geothermal heat flux datasets are tested under different experimental designs in a fully coupled model that mimics the control run of a typical Coupled Model Intercomparison Project (CMIP) climate model. The regional analysis herein reveals that bottom temperature and transport changes, due to the inclusion of geothermal heating, are propagated throughout the water column, most prominently in the Southern Ocean, with the background density structure and major circulation pathways acting as drivers of these changes. While geothermal heating enhances Southern Ocean abyssal overturning circulation by 20%–50%, upwelling of warmer deep waters and cooling of upper ocean waters within the Antarctic Circumpolar Current (ACC) region decrease its transport by 3–5 Sv (1 Sv = 10⁶ m³ s⁻¹). The transient responses in regional bottom temperature increases exceed 0.1°C. The large-scale features that are shown to transport anomalies far from their geothermal source all exist in the Southern Ocean. Such features include steeply sloping isopycnals, weak abyssal stratification, voluminous southward flowing deep waters and exported bottom waters, the ACC, and the polar gyres. Recently the Southern Ocean has been identified as a prime region for deep ocean warming; geothermal heating should be included in climate models to ensure accurate representation of these abyssal temperature changes.
3. Barnes, Jowan M., et al. “Idealised modelling of ocean circulation driven by conductive and hydrothermal fluxes at the seabed.” Ocean Modelling 122 (2018): 26-35. [FULL TEXT]   Geothermal heating is increasingly recognised as an important factor affecting ocean circulation, with modelling studies suggesting that this heat source could lead to first-order changes in the formation rate of Antarctic Bottom Water, as well as a significant warming effect in the abyssal ocean. Where it has been represented in numerical models, however, the geothermal heat flux into the ocean is generally treated as an entirely conductive flux, despite an estimated one third of the global geothermal flux being introduced to the ocean via hydrothermal sources.

   A modelling study is presented which investigates the sensitivity of the geothermally forced circulation to the way heat is supplied to the abyssal ocean. An analytical two-dimensional model of the circulation is described, which demonstrates the effects of a volume flux through the ocean bed. A simulation using the NEMO numerical general circulation model in an idealised domain is then used to partition a heat flux between conductive and hydrothermal sources and explicitly test the sensitivity of the circulation to the formulation of the abyssal heat flux. Our simulations suggest that representing the hydrothermal flux as a mass exchange indeed changes the heat distribution in the abyssal ocean, increasing the advective heat transport from the abyss by up to 35% compared to conductive heat sources. Consequently, we suggest that the inclusion of hydrothermal fluxes can be an important addition to course-resolution ocean models.

4. Downes, Stephanie M., et al. “Hydrothermal heat enhances abyssal mixing in the Antarctic Circumpolar Current.” Geophysical Research Letters 46.2 (2019): 812-821.  [LINK]  Upwelling in the world’s strongest current, the Antarctic Circumpolar Current, is thought to be driven by wind stress, surface buoyancy flux, and mixing generated from the interaction between bottom currents and rough topography. However, the impact of localized injection of heat by hydrothermal vents where the Antarctic Circumpolar Current interacts with mid‐ocean ridges remains poorly understood. Here a circumpolar compilation of helium and physical measurements are used to show that while geothermal heat is transferred to the ocean over a broad area by conduction, heat transfer by convection dominates near hydrothermal vents. Buoyant hydrothermal plumes decrease stratification above the vent source and increase stratification to the south, altering the local vertical diffusivity and diapycnal upwelling within 500 m of the sea floor by an order of magnitude. Both the helium tracer and stratification signals induced by hydrothermal input are advected by the flow and influence properties downstream.