Thank you Dr. ZF. Promoting discussion and cerebral calisthenics is never a waste of time or energy. I also admit to some confusion about the---- "N" for the mean of 1.5, e.g. 10 yr, 20 yr, etc. My personal measure has become where do we strike the bar for "net zero"? That is undefined until there is a global consensus that humans can adapt and maintain some sort of new homeostasis. IMHO. zf
Technically I always find it challenging when scientists give this explanation about one year or one month or [insert your favourite time period] above 1.5C, without giving away how the actual Paris Agreement defined the 1.5C goal. Well, you left comments open on this post so here I am. What is the Paris Agreement 1.5C limit to AGW? Is it the 5 year average? The 10 year? Something else entirely?
The last three paragraphs get at this a bit. There is not a technical definition of when 1.5C is passed, but the recent IPCC AR6 used the central point of a 20-year mean.
At risk of annoying people by not looking that up in the AR6 literature to check the justification given, do you think the 20 year mean is a sound choice based on natural global temperature volatility? I suspect there's a whole academic paper or even series of papers to be written on that if it doesn't exist already.
There's nothing magical about 1.5 deg C so there's nothing magical about any particular definition. That said, you don't want to use one year b/c of short-term variability (like we're having this year), so averaging over a decade (or two) is pretty reasonable. To be honest, I wouldn't sweat these thresholds that much. Our goal should be getting emissions down as fast as possible.
I totally agree - using average global temperature variation is as bad a measure of "what we don't want" as GDP is as a measure of what we do want. A firm definition would have been legally useful though. Climate litigation is a major driver of change, IMHO.
Question(s). The WMO says that the average GMT for 2022 was 1.15 - 1.02 to 1.28 C. How did they arrive at that number? What records/datasets or averages do they use to arrive at that number.? Is that number considered the "official" number?
Thanks. Maybe my question was poorly posed. I guess I see that but using their baseline all the records seem to vary less than the 0.2 degree variation that you describe in the text.
Maybe it is not that important but I'm trying to understand who is the "keeper" of the official global thermometer, i.e. who determines when we get to a certain number, e.g. 1.5?
Well, that WMO figure aligns all the datasets over the 1981-2010 period before adding in the average warming across all the datasets since preindustrial. So it rather forces agreement at the present.
But to your other question, there is no "official" keeper of global temperature records, each group provides its own analysis, though folks like the WMO and IPCC frequently summarize the results across the different temperature records.
Thank you Dr. ZF. Promoting discussion and cerebral calisthenics is never a waste of time or energy. I also admit to some confusion about the---- "N" for the mean of 1.5, e.g. 10 yr, 20 yr, etc. My personal measure has become where do we strike the bar for "net zero"? That is undefined until there is a global consensus that humans can adapt and maintain some sort of new homeostasis. IMHO. zf
Technically I always find it challenging when scientists give this explanation about one year or one month or [insert your favourite time period] above 1.5C, without giving away how the actual Paris Agreement defined the 1.5C goal. Well, you left comments open on this post so here I am. What is the Paris Agreement 1.5C limit to AGW? Is it the 5 year average? The 10 year? Something else entirely?
The last three paragraphs get at this a bit. There is not a technical definition of when 1.5C is passed, but the recent IPCC AR6 used the central point of a 20-year mean.
At risk of annoying people by not looking that up in the AR6 literature to check the justification given, do you think the 20 year mean is a sound choice based on natural global temperature volatility? I suspect there's a whole academic paper or even series of papers to be written on that if it doesn't exist already.
There's nothing magical about 1.5 deg C so there's nothing magical about any particular definition. That said, you don't want to use one year b/c of short-term variability (like we're having this year), so averaging over a decade (or two) is pretty reasonable. To be honest, I wouldn't sweat these thresholds that much. Our goal should be getting emissions down as fast as possible.
I totally agree - using average global temperature variation is as bad a measure of "what we don't want" as GDP is as a measure of what we do want. A firm definition would have been legally useful though. Climate litigation is a major driver of change, IMHO.
Suggestion #1: instead of criticizing the author before asking your question, how about just asking the question?
Suggestion #2: google it: https://www.carbonbrief.org/guest-post-interpreting-paris-agreements-1-point-5-c-temperature-limit/
Question(s). The WMO says that the average GMT for 2022 was 1.15 - 1.02 to 1.28 C. How did they arrive at that number? What records/datasets or averages do they use to arrive at that number.? Is that number considered the "official" number?
Pretty sure it’s just the WMO figure I included in this article, but with the baseline normalized to each records pre-1900 values.
Thanks. Maybe my question was poorly posed. I guess I see that but using their baseline all the records seem to vary less than the 0.2 degree variation that you describe in the text.
Maybe it is not that important but I'm trying to understand who is the "keeper" of the official global thermometer, i.e. who determines when we get to a certain number, e.g. 1.5?
Well, that WMO figure aligns all the datasets over the 1981-2010 period before adding in the average warming across all the datasets since preindustrial. So it rather forces agreement at the present.
But to your other question, there is no "official" keeper of global temperature records, each group provides its own analysis, though folks like the WMO and IPCC frequently summarize the results across the different temperature records.