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Messages - Richard Rathbone

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1
Science / Re: Comparison: forcings from CO2, CH4, N2O
« on: August 25, 2018, 05:44:53 AM »
"It appears to me that you are encouraging Ned W to use out of date methodology/values for calculating radiative forcing."

And it appears to me that Mr. Ned W. has the better arguments, and the better math.

sidd

2
Science / Re: Comparison: forcings from CO2, CH4, N2O
« on: August 21, 2018, 04:15:50 AM »
No, no, no.  We went over this exact point last year, and now ASLR is repeating the same incorrect claims. 

The big problem is that he's comparing apples to oranges.  ASLR cites Wikipedia as evidence that something called "CO2e" ("CO2 equivalent") was 528 ppmv (in 2017) and uses this to suggest that the IPCC's CMIP5 RCP 8.5 forcings are too low because their value for "CO2e" was projected to be only 425 ppmv in 2017.

That would be dramatic indeed -- the IPCC's fastest-warming scenario is already 100 ppmv too low after only a few years?!  But this is a fundamentally dishonest comparison.  ASLR is comparing numbers from two very different definitions of "CO2e":

* ASLR's Wikipedia number (528 ppmv) is based only on forcing from greenhouse gases. 

* ASLR's RCP 8.5 number (425 ppmv) is based on all anthropogenic forcings -- greenhouse gases, aerosols, black carbon, land-use albedo, everything.

What ASLR is doing is quite literally equivalent to suggesting that the IPCC has erroneously calculated the area of New York [city] because its number is much smaller than Wikipedia's value for the area of New York [state].   Yeah, they're both called "New York" but the numbers are based on two different definitions of "New York". 

That's the main problem with ASLR's comment.  The other curious thing is his reliance on an anonymous Wikipedia user for a greenhouse-gas-based value of CO2e (528 ppmv).  I could say more about that, but this comment is already too long and we went over all this a year ago already.

The total radiative forcings, RFs, from the linked ORNL website article by Blasing, T.J. (that updates such RF values reported in April 2016) are used in the linked Wikipedia article to calculate a CO2e value of 526.6ppm:

https://en.wikipedia.org/wiki/Carbon_dioxide_equivalent


Extract: "To calculate the CO2e of the additional radiative forcing calculated from April 2016's updated data: ∑ RF(GHGs) = 3.3793, thus CO2e = 280 e3.3793/5.35 ppmv = 526.6 ppmv."

http://cdiac.ornl.gov/pns/current_ghg.html

Per the following linked NOAA website the change in CO2e in 2017 was 1.6 ppm, which would give a total CO2e at the end of 2017 of about 528.2 ppm

https://www.esrl.noaa.gov/gmd/aggi/aggi.html

This value of 528.2ppm for CO2e for 2017 is well above the 425ppm value assumed by RCP 8.5 (used to force climate models for AR5, see the attached image).

3
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: August 17, 2018, 01:49:29 PM »
I'm happy to have this thread polluted with calls for action. The specifics at this point are doom porn. We have the information we need. It is time for action, starting with resolution on appropriate plan of action.

While cluttering the forum with off-topic posts might make you happy, our experience has shown that most users prefer more focused, on-topic discussions, especially in the most popular threads such as this one, so kindly stay on the rails. There are threads here for talking about policies and solutions; this isn't one of them. Thanks!

4
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: August 05, 2018, 10:55:39 PM »
Time to break out 2018's Arctic minimum running back chart (named after the way it will wiggle through a crowd of dots in a few weeks' time).

5
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: July 15, 2018, 11:34:08 AM »
Canadian Ice Service's daily maps definitely shows all that Hudson Bay sea ice still there.

https://www.canada.ca/en/environment-climate-change/services/ice-forecasts-observations/latest-conditions.html


6
Arctic sea ice / Re: The 2018 melting season
« on: July 05, 2018, 09:09:31 AM »
June 30 - July 4.

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