Summary of #56 William van Wijngaarden: Is Global Warming Hot Air?

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00:00:00 - 01:00:00

William van Wijngaarden, a professor of physics, presents his perspectives on climate change, clarifying various factors that attribute to the fluctuations in CO2 concentration, temperature, global warming, and its impact on nature. He explains how the graphical representation of CO2 concentration and temperature fails to depict the real causal relationship between them. Furthermore, he highlights the role of greenhouse gases such as carbon dioxide, methane, water vapor, nitrous oxide, and ozone, and their logarithmic function in increasing temperature. Van Wijngaarden also analyzes the global warming potential of these gases and explains how increasing CO2 levels benefit plant growth. Additionally, he advises more pragmatic and scientifically accurate approaches to understanding climate change than excessive alarmist campaigns.

00:00:00 In this section, William Van Weingarten, a professor of physics at York University, discusses climate change and greenhouse gases. He explains that gases such as water vapor, carbon dioxide, methane, nitrous oxide, and ozone absorb heat/infrared radiation, and that these gases have been increasing in the atmosphere over time. He shows measurements from Hawaii that demonstrate the increasing concentration of carbon dioxide, methane, and nitrous oxide, and explains that CO2 comes from burning fossil fuels, while nitrous oxide is a byproduct of fertilizer use. He also notes that the oxygen level in the atmosphere has been decreasing more than the CO2 increase, but this is because a lot of the CO2 is absorbed by plants or the ocean. Finally, he explains that the seasonal variation in CO2 concentration is due to plant growth and decay, and that there is more land mass in the Northern Hemisphere, leading to higher CO2 concentrations in the winter.
00:05:00 In this section of the video, William van Wijngaarden explains how CO2 concentration and temperature have been studied over time. Antarctic ice cores have been used to analyze CO2 concentration, with variations going up and down in time. Temperature has been measured by analyzing the concentration of isotopes of oxygen in the ice, which gives a measure of the temperature. While CO2 and temperature graphs do nicely go in sync on first glance, people have found that the CO2 goes up only 500 to 800 years after the temperature has gone up, suggesting that it is the temperature increase that causes the CO2 to come out of the ocean into the atmosphere, rather than the other way around.
00:10:00 In this section, William van Wijngaarden explains how temperature changes with altitude due to factors such as the absorption of ultraviolet light by ozone gas. He highlights the importance of considering the concentrations of various gases, including water vapor, carbon dioxide, ozone, methane, and nitrous oxide, when calculating their impact on temperature. When taking into account these greenhouse gases, the heat coming out of the Earth's atmosphere is altered, and the resulting curve is completely different to the one seen with a transparent atmosphere. Van Wijngaarden also highlights the importance of satellite observations, which have shown close agreement with the predictions made by the models.
00:15:00 In this section, William van Wijngaarden explains how the heat flux and intensity change with different frequencies and altitudes, giving examples over the Sahara, Mediterranean, and Antarctica. He explains how doubling the CO2 concentration barely makes a difference in the heat flux and describes the concept of CO2 saturation, where increased CO2 concentration doesn't necessarily cause a significant increase in temperature. He states that the temperature increase with CO2 concentration change follows a logarithmic function, making it difficult to achieve significant warming at higher concentrations. He concludes by presenting various curves of warming for different values of s.
00:20:00 In this section, William van Wijngaarden discusses the impact of clouds on climate change and the global warming potential of greenhouse gases. He shows how their effect differs from clear skies and that the influence of clouds will significantly reduce the forcing of CO2. He also explains the concept of the global warming potential, which measures the effectiveness of various greenhouse gases compared to CO2, and how the lifetime of these gases in the atmosphere is considered in the calculation.
00:25:00 In this section, the speaker discusses global warming potentials of different greenhouse gases and how they compare to CO2. Methane has a global warming potential of 85 relative to CO2 while nitrous oxide has a global warming potential of 233. However, the speaker argues that considering the global warming potential of these gases is not useful in understanding their impact and that we should instead consider the warming effect of one molecule of each gas compared to one molecule of CO2. The effect of the warming of methane is about one-tenth that of CO2, as we are adding about 300 times more CO2 molecules than methane molecules. Therefore, the increase of CO2 is estimated to be around 0.85 percent or 3.85 degrees Celsius per century, while the increase of methane is around 0.085 degrees per century.
00:30:00 In this section, William van Wijngaarden discusses the impact of fertilizers and the nitrogen gas and nitrous oxide produced as a result. He explains that although some countries want to curb the usage of fertilizers due to the emission of nitrous oxide, doing so can lead to a decrease of up to four times in agricultural yield, as the use of fertilizers is an important component of crop growth. Additionally, having more carbon dioxide in the atmosphere has many benefits, such as increased plant growth due to CO2 acting as a plant food. Plants also grow with less water due to CO2 causing the stomata in their leaves, which absorb CO2, to shrink.
00:35:00 In this section, the speaker discusses the data surrounding temperature increase versus year for the last 150 years. He notes that temperatures were relatively flat from 1850 to 1900, then increased from 1900 to about 1940, followed by a dip or flatness until 1975. From 1975 to 2000, temperatures increased by half a degree, but from 2000 to 2016, there was a surprising leveling off. The global climate models failed to predict this leveling off, suggesting that there are other factors, such as changes in the amount of energy sent to Earth by the sun or dramatic ocean currents, influencing temperature fluctuations. The speaker also explains that climate models may not be wholly accurate due to difficulties in accounting for clouds, and thus recommends some caution in interpreting the results of these models.
00:40:00 In this section, William van Wijngaarden discusses various climate factors that people commonly associate with global warming such as precipitation, forest fires, hurricanes, and polar ice caps. He looks at long-term precipitation data from various regions of the world and finds no significant overall trend of change. Similarly, forest fires, tornadoes, and hurricanes also do not show a consistent increase over time. Furthermore, he explains how people's management of forest ecosystems can affect the severity of forest fires. Lastly, van Wijngaarden discusses how the melting of polar ice caps is a dynamic and complex event influenced by regional factors.
00:45:00 In this section, the speaker discusses data from satellites over the last 40 years showing a definite downward trend in Arctic ice. However, there was a period of stability from 2007, possibly due to storms sweeping out the thick ice from the Arctic ice pack. The Antarctic has actually increased in size recently, although warmer temperatures will lead to less ice. The speaker warns against over-attributing glacial retreat to greenhouse gas increases, as much of it is likely due to warming up after the end of the little Ice Age. Sea level increases have been occurring for thousands of years since the last ice age ended, leading to the formation of an inner sea in present-day Holland.
00:50:00 In this section, William van Wijngaarden discusses sea level rise and ocean acidification. He notes that sea level has been rising for thousands of years due to natural processes and greenhouse gases may exacerbate this increase slightly, but are not solely responsible for it. He also explains that more CO2 in the atmosphere can cause ocean acidification, but the pH changes observed are not significant when compared to the natural fluctuations due to seasonal changes and depths of the ocean. Van Wijngaarden emphasizes the need to address overfishing and pollution, but points out that blaming CO2 for every detrimental effect on the ocean is not accurate.
00:55:00 In this section, William van Wijngaarden explains how the increase in greenhouse gases does cause some warming but it is small. He explains that the world has only warmed by about 1 degree C since 1850 and there has been no significant change in precipitation or storm frequency. Van Wijngaarden argues against outlawing fertilizers as it will reduce global food supply and suggests farmers instead work to optimize the use of fertilizers. Furthermore, he sheds light on the hysteria surrounding climate change stating that while Greta Thunberg has done an admirable job of inspiring people to take action, there are concerns about her understanding of the science behind climate change given how much school she has missed.

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