Radiative Forcing of Methane in Shortwave

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In summary: I'm not sure if the revised calculations have been agreed upon. The paper does mention that higher aerosol concentrations would lead to increased shortwave forcing of CH4, so it seems as though the authors' conclusions may be correct.
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Graeme M
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I was doing some reading about the extent to which methane absorbs in bands already dominated by water vapour and came across this paper. Two things stand out for me - first is that according to the authors the RF of methane is increased by 23% due to previously underconsidered shortwave absorption, and secondly their observation (in section 3.4 Uncertainties) that assuming zero aerosols (and therefore lowered albedo) results in a reduction in shortwave forcing of 10%.

Does anyone know if the authors' revised calculations have been agreed? Also, am I correct to think from this that higher aerosol concentrations would lead to increased shortwave forcing of CH4? Would that suggest that higher aerosol concentrations in the recent past (mid 20th century) would have contributed to larger total RF from greenhouse gases than has been thought? I had previously read (I think) that high aerosol concentrations had limited the rate of atmospheric warming.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016GL071930
 
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This is not my area. But. The paper you linked to has a nice feature called "cited by". In this case there is a number "91". This shows papers that cite, or "followup" on the paper you read. Click on the "91". You might see something useful.

Quite honestly some of the mentors have read the paper. Because of the way the authors seem to abbreviate two terms as "RF", we have trouble understanding things: RF as in shortwave and RF as in radiative forcing. Maybe we are totally off. Won't be the first time.

So I'm going to ping @Genava, who has a better understanding, and let's see what we get.
 
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Thanks Jim. Looking at some of those references indicates this paper has been accepted (for example, one paper notes that the authors "...use the latest well-mixed greenhouse gas (WMGHG) radiative forcing (Etminan et al. 2016; Meinshausen et al. 2017) "
 

1. What is radiative forcing of methane in shortwave?

Radiative forcing of methane in shortwave refers to the measure of the change in the Earth's energy balance caused by the presence of methane in the atmosphere. It is a measure of the warming effect of methane on the Earth's surface and is expressed in watts per square meter (W/m2).

2. How does methane contribute to radiative forcing?

Methane is a potent greenhouse gas that absorbs and emits radiation in the shortwave portion of the electromagnetic spectrum. When methane is present in the atmosphere, it absorbs and traps heat, leading to an increase in the Earth's overall temperature. This is known as the greenhouse effect and is the main contributor to radiative forcing.

3. What are the sources of methane emissions?

The main sources of methane emissions include natural sources such as wetlands, termites, and wildfires, as well as human activities such as agriculture, landfills, and fossil fuel production. Methane can also be released from natural gas leaks and during the production and transport of coal.

4. How does the radiative forcing of methane compare to other greenhouse gases?

In terms of global warming potential, methane is a more potent greenhouse gas than carbon dioxide. However, carbon dioxide is present in much higher concentrations in the atmosphere, making it the main contributor to radiative forcing. Methane has a shorter lifespan in the atmosphere compared to carbon dioxide, but it has a stronger warming effect during that time.

5. What are the potential impacts of increased radiative forcing from methane?

The increased radiative forcing from methane can lead to a range of impacts, including higher global temperatures, changes in weather patterns, melting of polar ice caps, and rising sea levels. It can also have negative effects on human health, agriculture, and ecosystems. Reducing methane emissions is crucial in mitigating these impacts and addressing climate change.

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