SGC Virtual Excursions
May 5 2024, Cumberland Hall
Making Sense of Climate Change Virtual Excursion: Global warming is mainly driven by rising concentrations of carbon dioxide in the atmosphere, which are mainly caused by human activities. Currently, we do not have any method to remove a lot of carbon from the atmosphere. The history of this constant struggle between human energy demands and planetary needs dates way back to the birth of agriculture. The CO2 concentrations rose, stimulating plant growth, thus allowing for the birth of agriculture. Fast forward to the modern era, and the Keeling curve really showed how dire the situation was. Many people fought, saying that the ocean would absorb all of it, but research has shown that the carbon in the water doesn't move; it creates layers. In the 1800s, Fourier helped us learn the sources of heat and how the asymmetry of incoming visible and outgoing infrared was causing the atmosphere to warm. John Tyndall discovered how water vapor and carbon dioxide block infrared radiation, and the greenhouse effect was discovered just 30 years later. Years later, Landley invented a device to measure infrared radiation, hoping to one day predict the weather on Earth. In 1896, Arrhenius published his calculations of global warming being caused by human emissions, where he applied Langley atmospheric data and predicted that rising CO2 from burning coal would change the climate. The Callendar Effect in 1938 and, finally, the Roger Revelle revelation in 1956 marked two distinct scientific achievements within climate science. Due to all of this, scientists discovered that the rise of CO2 was man-made. The usage of fossil fuels, which are rich in carbon 12, led to the atmosphere being pumped with carbon 12. As a lighter carbon, the plants on the surface of the planet are all considered to be more efficient for a heavier carbon type called Carbon 13. Because of this, carbon 13 concentrations are plummeting, and the rise of carbon 12 will continue. Many people also think that the fluctuations in the Earth’s orbits, volcanoes, and solar flares could be a cause, but none of them change the Earth’s temperature as drastically as greenhouse gases do.
In general, I agree with the main points. I have always advocated for climate change and going green from a young age. It all started when I went to India, and the amount of trash and disregard for the environment there was disgusting, and I wanted to do something about it. The main points within the video convinced me even more. By starting at the very base of climate change and the birth of agriculture, the presenter set a good context so I could understand the rest of the presentation. The discoveries by climate scientists, specifically Keeling, were vital in understanding that the effects on the Earth’s temperature are because of humans instead of other natural factors. The fact that the ocean ‘could’ suck up all of the carbon is also a bad point because carbon creates layers in the ocean, and at some point within the modern era, the ocean stopped absorbing a lot of the carbon in the atmosphere. Fourier’s explanations with thermodynamics allied us to explain how heat travels in conduction, convection, and radiation forms. The sources of heat are the sun, Earth’s interior, and space, while the only way to lose heat is through outgoing infrared. The asymmetry of incoming visible and outgoing infrared causes the atmosphere to warm. All this has culminated in an attempt to explain the greenhouse effect, basically summarizing and talking about how certain molecules trap radiated heat within the Earth’s atmosphere. Both water vapor and carbon dioxide are two known gases that block infrared radiation, according to John Tyndall in 1829. Samuel Landley invented a device to measure infrared radiation within the atmosphere one day, hoping it could predict Earth’s weather. I feel like this was the point that they could have explained better because the common man cannot draw connections between how measuring infrared could help predict something that is so unpredictable as Earth's weather. I still don't really understand it. By applying Langley’s atmospheric data, Arrhenius published the calculations, which will be a baseline for tracking how carbon dioxide will change the atmosphere if more coal is burned during the Industrial Revolution. The Callednar effect was a very convincing graph showing increasing temperatures through the early half of the 20th century. The oceanic absorption came back around 1956 to be reinforced when Roger Revelle stated that 80% of CO2 in the atmosphere would stay because the ocean would not be able to absorb it. The science makes sense when they go into depth about how the atmosphere is created. Water vapor is the most dominant greenhouse gas, accounting for about 60% of them. Because of this, a net positive feedback loop is created where global temperatures tend to rise, creating more water vapor in the atmosphere, thus increasing greenhouse warming from water vapor overall, and it starts all over again. Finally, they checked if other natural factors fluctuated as much as the Earth’s temperature, and they clearly didn't, with greenhouse gases being the only ones, so you must rule out natural factors. All in all, the conclusion the presenter landed upon was clear cut, except they didn't show much evidence that contradicted their points which weakens their argument. They could have acknowledged evidence against them and then explained why it was wrong.
Nuclear Accidents Virtual Excursion: The presentation shows how the world during the Cold War era erroneously shifted towards plutonium as a fuel source due to perceived Uraniuk scarcity (which wasn't exactly true). Events such as Chernobyl showed how vulnerable nuclear reactors are and spurred the United States to create the NRC (Nuclear Regulation Committee). Concepts such as Design Basis Accidents and Defense in Depth emerged to mitigate risks with these huge reactors. During simulation runs within the USAA, the NRC would predict that LBLOCA (large shear break in cooling pipes) was the main reason for core meltdown. However, WASH-1300 identified a blackout (a complete electrical equipment outage) as the biggest contributing factor. This stressed the importance of small-break accidents, which can cause a breakdown. The Three Mile incident illustrated a partial core meltdown due to coolant failures, while the containment structure was still resilient. The lessons learned from this include improving human factors, emergency procedures, and hardware modifications. The Chernobyl accident happened because of human errors. Operators were running rush tests on the RBMK reactors and disabled their safety systems, causing a catastrophic steam explosion and widespread radioactive contamination. The Fukushima accident was caused by a massive earthquake leading to a tsunami, which shut down the diesel generators, leading to a complete blackout and disabling the cooling systems. This led to a complete meltdown. Studies on these core meltdown mitigation strategies allowed the US plants to be prepared for such scenarios.
The main points were convincing in the way that they urged me to push for more regulatory actions taken on nuclear power plants within the USA. Chernobyl and the Three Mile Island accidents were both partly human errors where the operators of both plants were complacent and lazy. Chernobyl is a milestone when it comes to operator laziness; they even turned off the safety valves just to pass a test. Three Mile Island had more equipment errors because the loss of feedwater led to a small LOCA and an open valve. The cooling system couldn't do what it was supposed to do, and the partial meltdown was the result of this. The human error was that the operators shut down all operations right after they realized the catastrophe they had in their hands, but they didn't realize that about 7% of the fuel keeps burning even after a complete shutdown due to half-life decay. Both of these accidents led to much stricter regulatory practices within US power plants. As for evidence that could contradict these points, there is only a little. There is only one outcome when it comes to nuclear power plant accidents, and that is loss of life, loss of property, and loss of money, so no one is against stronger nuclear regulations. However, for both Chernobyl and the Three Mile Incident, there are different theories on what systems or instruments failed and what led to that outcome. For example, Chernobyl had two steam explosions, and the cause of the second one is completely unknown. In the Three Mile Island incident, there were people debating whether it was more of a mechanical failure or human error. Could communication breakdown or the stuck open valve be the real reason why the core almost melted? The presenter didn't go into details about the nuanced perspectives on each of these accidents but instead imposed his own point of view on the audience. His perspective is valid, as he held a high position with the NRC and was involved with a lot of nuclear regulation within the USA. He would study what went wrong with European and Asian plants and make sure US plants did not suffer the same mishaps. The Japanese plant, Fukushima, was in complete mechanical failure (everyone agrees on this) due to an electrical blackout caused by a tsunami. During the blackout, many different operators and workers even rushed to their cars for batteries in order to see what was wrong. Because of this accident, it makes sense why US power plants are now equipped with portable generators, backup generators, portable pumps, etc. They have so many backup electrical systems that the power plants could last about 8 hours in a complete blackout and not experience any sort of core damage. This point was the most convincing to me because there was no debate on what the cause was for the core meltdown and how that translated to US power plants being better equipped for electrical blackouts.