As always, very helpful lesson. It explains why it often feels warmer in the cities than in the surrounding areas and why people who stay up late using artificial lighting unwittingly contribute to global warming.
🎯 Key Takeaways for quick navigation: 00:06 *🌊 Understanding Light and Waves* - Introduction to the concept of light as waves and the principle of wavelength. - Light is composed of incredibly small waves that are invisible to the naked eye. - Different wavelengths of light are perceived as different colors by the human eye. 02:06 *🎨 Color Perception through Wavelengths* - Explanation of how our eyes and brain perceive colors through different wavelengths of light. - Illustration of the spectrum of light coming from the sun, including visible and invisible parts (UV and infrared). 05:45 *🌡️ Introduction to Infrared and UV Light* - Differentiation between UV (ultraviolet) and infrared light in relation to human perception. - The role of the ozone layer in blocking most UV light, with a focus on the small segment that reaches Earth's surface. 10:18 *🌍 Greenhouse Effect and Radiation Categories* - Division of solar radiation into shortwave (visible and UV) and longwave (infrared) categories. - Explanation of Earth's process of absorbing shortwave radiation and emitting longwave radiation. 14:28 *🏭 Demonstrating the Greenhouse Effect through Simulation* - Simulation demonstrating how greenhouse gases like water vapor, CO2, and methane interact with longwave radiation. - Comparison of how different gases absorb and reradiate energy, highlighting the unique behavior of greenhouse gases. 21:19 *❄️ Hypothetical Earth Without Greenhouse Gases* - Discussion on the impact of the absence of greenhouse gases on Earth's temperature and environment. - Theoretical temperature of Earth without greenhouse gases and the implications for life and the planet's surface. 25:54 *☁️ Effect of Clouds on Earth's Temperature* - Analysis of how clouds can reflect shortwave radiation and trap longwave radiation, influencing day and night temperatures. - The role of clouds in cooling the Earth during the day and warming it during the night through the reflection of radiation. 30:03 *🌱 Necessity of the Greenhouse Effect for Life* - Explanation of the greenhouse effect's crucial role in maintaining Earth's habitable temperature. - Discussion on the human contribution to the greenhouse effect and the resultant climate change issues. 34:07 *💨 Overview of Greenhouse Gases and Their Impact* - Differentiation between naturally occurring and synthetic greenhouse gases. - Focus on CO2, CH4, and N2O as key contributors to the greenhouse effect and their varying strengths and lifetimes in the atmosphere. 39:04 *📊 Comparing Greenhouse Gas Emissions* - Methodology for comparing the impact of different greenhouse gas emissions using CO2 equivalent and Global Warming Potential (GWP). - Example calculation to determine which of three hypothetical factories contributes most to the greenhouse effect based on their specific gas emissions. 41:30 *📊 Calculating Greenhouse Gas Contributions* - Converting greenhouse gas emissions to CO2 equivalent to compare their impact. - Demonstrates how different gases contribute to the greenhouse effect based on their global warming potential. 45:08 *🇺🇸 Breakdown of U.S. Greenhouse Gas Emissions* - Overview of the major greenhouse gases emitted in the United States, converted to CO2 equivalent. - Highlights CO2 as the predominant greenhouse gas emitted, despite the higher global warming potential of other gases. 47:34 *⚡ Sources of CO2 Emissions* - Discusses the primary sources of CO2 emissions, with fossil fuel combustion being the most significant. - Outlines the significant contribution of electricity generation and transportation to CO2 emissions. 50:43 *🐄 Methane Emissions and Sources* - Explains the major sources of methane emissions, including enteric fermentation, natural gas systems, and landfills. - Emphasizes the significant impact of agricultural practices, particularly from livestock, on methane emissions. 52:04 *🌱 Nitrous Oxide Emissions Analysis* - Breaks down the sources of nitrous oxide emissions, with agricultural soil management being the largest contributor. - Discusses the role of synthetic fertilizers in increasing nitrous oxide levels in the atmosphere. 53:26 *🌍 Greenhouse Gas Emissions and Removals Overview* - Provides a comprehensive overview of the sources and sinks of greenhouse gases in the United States. - Highlights the dominance of the energy sector in greenhouse gas emissions and the role of agriculture and industrial processes. Made with HARPA AI
Question: do short wave radiation transforms into long wave radiation (by loosing energy) when hitting co2 or methane as well or GHG? I thought this was also a possibility. Thank you! Your lectures are amazing!
~4:00 The question of why there are no green stars is an interesting one. You can have a star whose radiation peaks (broadly) at a green wavelength, but it's not going to look green.
~49:00 Just my opinion, but I generally find global stats on this stuff more interesting than just for the US. For one thing, that takes care of any effects due to such things as offshoring of manufacturing.
Now think about the fact that China, the largest global manufacturer, has no emissions regulations in place and what that means not only for their air quality but the greenhouse effect worldwide. Companies outsourcing their production there are responsible and should be taxed extra.
If we had no GHGs, presumably the Planet would freeze over, and the albedo would increase greatly. That would make things even colder. Does that 4 F estimate include that effect?
That is part of the 'snowball earth' hypothesis - once the oceans freeze, the albedo increases, and then the Earth is 'stuck' in that state for quite a while. There is good evidence this has happened at least once, and possibly more in Earth's history.
Hello again Komand'r. I'm not exactly sure what you are asking...the human eye can usually see wavelengths of light between 380nm - 700nm. nm = nanometer, which is one billionth of a meter. But I'm not sure this is actually your question.
@@MelStrong Hi there. First of all, thank you for answering me. A couple of day ago i looked at the sun with a pare of sun glases, through a window and i saw kinda some line colors, like a rainbow all kinds of colors from purple to red. So can you tell me , red is the last visible color of wavelenghts, and between what measurements do we see red color? Thank you
GWP: *I don't think this is a sufficient explanation.* A GHG has a certain amount of heat-trapping activity on an instantaneous basis, and you could rank the different gases according to that. But you could also rank them according to their cumulative heat-trapping potential over their different lifetimes-which, as said here, are radically different. Which of those estimates you use, or whether you use something intermediate, would depend on what consequences you are trying to assess.
@@MelStrong That would make sense if done consistently, but I keep hearing things said like: CH4 is 100X as strong as CO2 over 20 years, and 20X as strong over 100 years. I think that's really confusing, and things shouldn't be put that way. Also, some of these GHG have SUCH long lifetimes that a cumulative total is not going to be very relevant to the concerns of anyone alive right now.
It is misleading to draw the outgoing long wave radiation at the angle of reflectance of the incoming short wave radiation. The long wave radiation is emitted in all directions day and night.
Super helpful way to visualize what each term means. Thanks - and love the cat!
As always, very helpful lesson. It explains why it often feels warmer in the cities than in the surrounding areas and why people who stay up late using artificial lighting unwittingly contribute to global warming.
🎯 Key Takeaways for quick navigation:
00:06 *🌊 Understanding Light and Waves*
- Introduction to the concept of light as waves and the principle of wavelength.
- Light is composed of incredibly small waves that are invisible to the naked eye.
- Different wavelengths of light are perceived as different colors by the human eye.
02:06 *🎨 Color Perception through Wavelengths*
- Explanation of how our eyes and brain perceive colors through different wavelengths of light.
- Illustration of the spectrum of light coming from the sun, including visible and invisible parts (UV and infrared).
05:45 *🌡️ Introduction to Infrared and UV Light*
- Differentiation between UV (ultraviolet) and infrared light in relation to human perception.
- The role of the ozone layer in blocking most UV light, with a focus on the small segment that reaches Earth's surface.
10:18 *🌍 Greenhouse Effect and Radiation Categories*
- Division of solar radiation into shortwave (visible and UV) and longwave (infrared) categories.
- Explanation of Earth's process of absorbing shortwave radiation and emitting longwave radiation.
14:28 *🏭 Demonstrating the Greenhouse Effect through Simulation*
- Simulation demonstrating how greenhouse gases like water vapor, CO2, and methane interact with longwave radiation.
- Comparison of how different gases absorb and reradiate energy, highlighting the unique behavior of greenhouse gases.
21:19 *❄️ Hypothetical Earth Without Greenhouse Gases*
- Discussion on the impact of the absence of greenhouse gases on Earth's temperature and environment.
- Theoretical temperature of Earth without greenhouse gases and the implications for life and the planet's surface.
25:54 *☁️ Effect of Clouds on Earth's Temperature*
- Analysis of how clouds can reflect shortwave radiation and trap longwave radiation, influencing day and night temperatures.
- The role of clouds in cooling the Earth during the day and warming it during the night through the reflection of radiation.
30:03 *🌱 Necessity of the Greenhouse Effect for Life*
- Explanation of the greenhouse effect's crucial role in maintaining Earth's habitable temperature.
- Discussion on the human contribution to the greenhouse effect and the resultant climate change issues.
34:07 *💨 Overview of Greenhouse Gases and Their Impact*
- Differentiation between naturally occurring and synthetic greenhouse gases.
- Focus on CO2, CH4, and N2O as key contributors to the greenhouse effect and their varying strengths and lifetimes in the atmosphere.
39:04 *📊 Comparing Greenhouse Gas Emissions*
- Methodology for comparing the impact of different greenhouse gas emissions using CO2 equivalent and Global Warming Potential (GWP).
- Example calculation to determine which of three hypothetical factories contributes most to the greenhouse effect based on their specific gas emissions.
41:30 *📊 Calculating Greenhouse Gas Contributions*
- Converting greenhouse gas emissions to CO2 equivalent to compare their impact.
- Demonstrates how different gases contribute to the greenhouse effect based on their global warming potential.
45:08 *🇺🇸 Breakdown of U.S. Greenhouse Gas Emissions*
- Overview of the major greenhouse gases emitted in the United States, converted to CO2 equivalent.
- Highlights CO2 as the predominant greenhouse gas emitted, despite the higher global warming potential of other gases.
47:34 *⚡ Sources of CO2 Emissions*
- Discusses the primary sources of CO2 emissions, with fossil fuel combustion being the most significant.
- Outlines the significant contribution of electricity generation and transportation to CO2 emissions.
50:43 *🐄 Methane Emissions and Sources*
- Explains the major sources of methane emissions, including enteric fermentation, natural gas systems, and landfills.
- Emphasizes the significant impact of agricultural practices, particularly from livestock, on methane emissions.
52:04 *🌱 Nitrous Oxide Emissions Analysis*
- Breaks down the sources of nitrous oxide emissions, with agricultural soil management being the largest contributor.
- Discusses the role of synthetic fertilizers in increasing nitrous oxide levels in the atmosphere.
53:26 *🌍 Greenhouse Gas Emissions and Removals Overview*
- Provides a comprehensive overview of the sources and sinks of greenhouse gases in the United States.
- Highlights the dominance of the energy sector in greenhouse gas emissions and the role of agriculture and industrial processes.
Made with HARPA AI
Loose love loooooooove this, pls share comrades
Question: do short wave radiation transforms into long wave radiation (by loosing energy) when hitting co2 or methane as well or GHG? I thought this was also a possibility. Thank you! Your lectures are amazing!
~4:00 The question of why there are no green stars is an interesting one. You can have a star whose radiation peaks (broadly) at a green wavelength, but it's not going to look green.
~49:00 Just my opinion, but I generally find global stats on this stuff more interesting than just for the US. For one thing, that takes care of any effects due to such things as offshoring of manufacturing.
Now think about the fact that China, the largest global manufacturer, has no emissions regulations in place and what that means not only for their air quality but the greenhouse effect worldwide. Companies outsourcing their production there are responsible and should be taxed extra.
If we had no GHGs, presumably the Planet would freeze over, and the albedo would increase greatly. That would make things even colder. Does that 4 F estimate include that effect?
That is part of the 'snowball earth' hypothesis - once the oceans freeze, the albedo increases, and then the Earth is 'stuck' in that state for quite a while. There is good evidence this has happened at least once, and possibly more in Earth's history.
Hello dear Mel, can you please tell me where exactly do we see all these visible colors?
Hello again Komand'r. I'm not exactly sure what you are asking...the human eye can usually see wavelengths of light between 380nm - 700nm. nm = nanometer, which is one billionth of a meter. But I'm not sure this is actually your question.
@@MelStrong Hi there. First of all, thank you for answering me. A couple of day ago i looked at the sun with a pare of sun glases, through a window and i saw kinda some line colors, like a rainbow all kinds of colors from purple to red. So can you tell me , red is the last visible color of wavelenghts, and between what measurements do we see red color? Thank you
GWP: *I don't think this is a sufficient explanation.* A GHG has a certain amount of heat-trapping activity on an instantaneous basis, and you could rank the different gases according to that. But you could also rank them according to their cumulative heat-trapping potential over their different lifetimes-which, as said here, are radically different. Which of those estimates you use, or whether you use something intermediate, would depend on what consequences you are trying to assess.
GWP calculations are for atmospheric lifetimes, so they are cumulative as I think you are thinking.
@@MelStrong That would make sense if done consistently, but I keep hearing things said like: CH4 is 100X as strong as CO2 over 20 years, and 20X as strong over 100 years. I think that's really confusing, and things shouldn't be put that way.
Also, some of these GHG have SUCH long lifetimes that a cumulative total is not going to be very relevant to the concerns of anyone alive right now.
Why have I never learned this in middle/high school?
It is misleading to draw the outgoing long wave radiation at the angle of reflectance of the incoming short wave radiation. The long wave radiation is emitted in all directions day and night.
Nah, I think everyone understands that without telling
Hy Mel, do you have a facebook acount? How can I contact you?