Tonight, my great and good friends of the Secret Science Club are presenting a Zoom lecture featuring oceanographer, climate scientist, and Antarctica explorer Dr Joellen Russell of the University of Arizona. Dr Russell also serves co-chair of the NOAA Science Advisory Board’s Climate Working Group, heading up the Southern Ocean Carbon and Climate Observations and Modeling team. She is also a founding member of Science Moms.
Dr Russell, appropriately, greeted the audience with an 'ahoy', and told us that she had a story for us. She began her lecture with Voyager's picture of the pale blue dot that Carl Sagan urged NASA to photograph. She noted that Planet Earth is better called Planet Water, the surface of the planet being 72% water. She then displayed the Earth Systems Model, a computer simulation of the planet.
The Keeling Curve is a diagram of carbon dioxide measurements taken from Mauna Loa and the South Pole. Even during the pandemic, carbon emissions rose, driven by forest fires and ocean warming which expelled CO2. In her home in Tuscon, there were heat waves, long-term drought, and a flood driven by a monsoon.
Global warming is ocean warming. Sunlight radiates onto the earth, and most of it radiates back into space. Certain gases, such as carbon dioxide, trap the heat in the planetary system. 93% of this heat differential effects the ocean. She then talked about the carbon dioxide issue- the government declared greenhouse gases pollutants. In 2007, the government required cutting greenhouse gas emissions.
85% of the increasing CO2 is the result of burning fossil fuels, 15% is the result of deforestation and land use changes.
Using the oceans to sequester CO2 poses problems, such as the release of the gas due to natural cycles, such as loss of solubility due to warming. The planet has gotten windier, which stirs the ocean, prompting CO2 release. Wave height can be measured with radar. This ocean-mixing is getting deeper. Simulations have mapped the air-sea carbon flux, but they have to be verified by observation, typically done at sea.
From 1999 to 2015, 585,652 ship-borne temperature measurements were made, but robot (Argo) floats made 1,485,744 measurements in the same time period. There are only about 6,000 oceanographers currently working.
The Argo floats are biogeochemical floats descend to a depth of 1000 meters, then continue a descent to 2000 meters, measuring temperature, pressure and salinity. The floats drift, which allows them to be deployed without the permits that propelled probes would necessitate. Analysis of the data can be conducted aboard ship in realtime.
The Southern Ocean around Antarctica is the blender in which the global ocean is mixed- it takes up to 50% of the carbon dioxide, and up to 75% of the heat. Why does Dr Russell study the sea around Antarctica? This is where the fate of Arizona will be decided. The world is deeply, profoundly connected. The Southern Ocean is a critical, yet precarious, carbon cycling engine.
Cool water upwells from the depths, driven by the extreme winds which displace water higher in the water column. This water carries carbon-rich detritus from the ocean floor, even though most decaying material never reaches the bottom. This seafloor carbon is one of the most significant carbon sources which is going to pose a problem.
SOCCOM measures air-sea carbon flux- high carbon deep waters reach the surface. Pathways of high carbn spiral upward, and are taken into the atmosphere. Better models can lead to better predictions of climate patterns globally. Weather models are now more properly called climate models, which take into account ocean conditions.
Progress toward real-time carbon accounting is occurring. Dr Russell's goal is a real-time carbon accounting and climate model, so better predictions can be made. The ultimate goal is to make this a better
The lecture was followed by a Q&A session. Some Bastard in the audience asked about the possibility of the upwelling of methane hydrates. Dr Russell noted that she's a chemist, the methane issue is 95% dependent on pressure, so a wholesale release of methane is unlikely, though local conditions, such as a landslide, can reduce pressure. Another question regarded carbon sequestration, and Dr Russell waxed rhapsodic about trees, which are literally made of air, using carbon dioxide for photosynthesis.
What is the most important thing to bring on an expedition? Chapstick, though she always brings antibiotic ointment, blocks and blocks of chocolate to bribe the crew, and coffee, including coffee beans to chew. She joked that anyone yearning to go to sea should leave a leaf blower running on their kitchen table for a month. There is constant engine noise, intense winds, hundred-foot waves. Chapstick is necessary. Also, don't skimp on buying gloves. If you are hurt, you lose measurement time, if you miss a measurement, that data is forever lost. I'm going to note that Dr Russell is a gifted comedian.
Regarding carbon emissions during the pandemic, our vehicle emissions dropped, but home heating and air condition usage increased. The air quality in New Delhi dramatically improved. The wildfires in the Northern Hemisphere added tons of carbon into the atmosphere. We also experienced a hot La Niña, which increased ocean upwelling.
Another question involved the role of ocean upwelling on the melting of the Antarctic ice shelves. Some of the models didn't take into account melting in Antarctica and Greenland, which she considers crazy. The ice sheets are thinning and the freshwater sitting on top of the ocean water can trap heat in the water at a depth of about 600 meters. This cap raises the water temperature by about four degrees, driving additional melting. She described this finding as a watershed.
Regarding ice ages, Dr Russell indicated that we put so much CO2 into the atmosphere that there will be no other glacial advance- the warming atmosphere, the increased winds, the 'burping' of CO2 into the atmosphere... this synergy has overloaded the system.
Another question involved the next phase of the research- Dr Russell indicated that she wants to go from two measurements of wind speeds to four measurements to measure peak winds, the winds that most drive carbon flux. There is no way to make up for missing peak winds when making models. She needs realtime carbon budget, and the satellites to accomplish this. She also wants to better measure coastal carbon budgets, which would necessitate the use of gliders, and a denser floater array. There is plenty to do, and she wishes that our global partners would further help in funding. She joked that the Germans had the flimsiest floats with the least impressive engineering.
Regarding the recyclability of the Argo floats- their housing is edible... as the floats approach the end of their lifespan, they will sink and biodegrade until organisms can consume the material. Regarding the float bot costs, a particular cable (RF resistant, salt resistant) increased in price from about $2 apiece to about $1000 apiece. Tank tests are difficult, they need to operate in the inky depths. The floats can be reprogrammed remotely though, a couple of lines of code to change operational ranges and avoid hazards. Each float measures temperature, pressure, and salinity, diving two thousand meters over the course of ten days. The floats also have two optical sensors, a chlorophyll fluorescence and backscatter to measure growing and pooping. There are also oxygen and Ph (increased carbon increases acidity) sensors. There are also other possible projects for realtime carbon accounting- Boeing offered to install carbon sensors in the noses of their planes, but NOAA didn't have the budget to provide the sensors. This is a low-cost, minimally damaging program, but there wasn't the will to push it. Dr Russell also noted that we don't have a civilian ocean forecast system. In 2004, NOAA declared there was no budget for it, but the EU has such a system.
Another question regarded the effect of fresh meltwater on ocean currents- the only current which is not speeding up is the Labrador Current, which is effected by an influx of fresh water. This upsets the hydrological cycle of the planet and is a Big Deal. The older model of slowing currents has been refuted by observation.
The last question involved the role of seismic activity in oceanic warming- Dr Russell indicated that it typically doesn't. They do monitor seismic activity in active subduction zones. The majority of carbon emitted doesn't come from hydrothermal vents, but from volcanoes. She stressed that her goal is to measure every carbon molecule.
Once again, the Secret Science Club delivered a fantastic lecture. This particular lecture hit what I call the Secret Science Sweet Spot, that blend of hard science, adventure narrative, and advocacy, all accompanied by vivid graphics, that is so appealing to me. Kudos to Dr Russell, Margaret, and Dorian for an informative, entertaining, and enlightening program.
Here's a brief video of Dr Russell discussing the Southern Ocean:
Here's a longer video regarding the subject of the measuring array:
Pour yourself a nice beverage and soak in that SCIENCE!
No comments:
Post a Comment