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Astronomy - Ch. 9.1: Earth's Atmosphere (39 of 61) How Does Increasing CH4 Change G.H. Effect?
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- čas přidán 17. 10. 2018
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In this video I will discuss how does the increase concentration of CH4, methane, changes the greenhouse effect. There has been a 125% increase in the concentration of the atmospheric methane from 1850 to 2018. How did that increased methane affect the greenhouse effect?.
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Next video in this series can be seen at:
Visit ilectureonline.com for more math and science lectures!
In this video I will discuss how does the increase concentration of CH4, methane, changes the greenhouse effect. There has been a 125% increase in the concentration of the atmospheric methane from 1850 to 2018. How did that increased methane affect the greenhouse effect?.
Next video in this series can be seen at:
• Astronomy - Ch. 9.1: E...
I hear more and more that Methane is a huge problem for our climate. They always talk about that Methane‘s climate sensitivity is factor 28 compared to CO2. But this makes no sense to me. Can you please explain this?
Explaining that would take several pages, but let me give you a bit of insight. The claims you mentioned are made in the absence of some key scientific information, some of which is mentioned in this series of videos. Essentially the wavelengths that the methane molecule can absorb tends to overlap with those of water vapor, and the few that do not overlap tend to be saturated, which means that methane already absorbs the vast majority of the energy in those wavelenght bands and cannot absorb much more. What you will not see mentioned is that methane levels have increased 250 to 300 % over the last few hundred years with virtually no effect on the climate. In comparison they have been relatively stable over the last 30 years or so.
Thanks for your explanation sir
I assume that the absorption that is shown looks like this for average water vapor concentrations around 15 degC. But how much energy would be absorbed by CH4 in a cold night in the desert with say 5% humidity? Could not CH4 play a much bigger role than 1% (and CO2 even more) under such weather conditions that are typical for large areas of the planet (Sahara and other large deserts) ?
True that the numbers are averages and do change somewhat for different locations of the world. However 3/4 of the surface is water and even in the driest places of the Earth, water vapor still play the most significant role in the greenhouse effect.
In a cold night in the Sahara desert temperatures can fall below -15 C. So I was assuming that in such dry areas there is close to no water vapor greenhouse effect left and the biggest greenhouse effect under such dry circumstances would come from CO2. But you think obviously that this does not seem to be the case since even superdry air is still full of H2O molecules.
Concerning size: Yes, only around 1/3 is land but thereof around 1/3 is desert so in case CO2 would play a significant role there it could be something that can not be neglected.
I would love to see the diurnal temperature ranges over the last 100 years from such ultra dry areas. In case that has not changed much then the CO2 increase does not even play a role under such extreme dry conditions (and even far less in the other more humid 90% of the surface). In case it has decreased significantly that would actually support that CO2 has an impact to at least 10% of the worlds area.
Even during the driest winter periods, the desert air contains much more water vapor than CO2. Also water vapor absorbs a much greater percentage of the radiated spectrum from the surface. A slight correction to the above estimates: Earth's land area (including lakes and rivers) comprises about 29% of Earth's total surface and desserts (not including Antarctica) comprise about 12% of the total land area which means that deserts makes up about 3.5 % of the total surface of the Earth.
Respect from lovely India.
Yes indeed and welcome to the channel
Dear teacher if u read or sometimes Look the comments blow plz and plz may you start us series Lectures about Geology or Geological Engineering Althoug i found, liked ur Lessons about Astronomy or Eaths Atmospher part ....dear teacher how can i feel that u saw my massage 🙏🙏🙏🙏🙏 plz asnwer me ..
v.need Lessons About Geology 🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏
Hi, yes Geology is part of the plan, but there is just the two of us and we have our regular day jobs as well (and we have a lot of other requests as well). I am not sure we can do this in the time frame you are looking for.