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A thread on some things in the
AIR Report Quantifying Climate the Impacts of Climate Change
1/17
https://www.air-worldwide.com/siteassets/Publications/White-Papers/documents/air_climatechange_us_hurricane_whitepaper.pdf
AIR Report Quantifying Climate the Impacts of Climate Change
1/17
https://www.air-worldwide.com/siteassets/Publications/White-Papers/documents/air_climatechange_us_hurricane_whitepaper.pdf
Upfront, the whole exercise rests on assumptions embedded in IPCC's RCP 8.5.
2/17
2/17
In recent years and coming to a head in 2020, researchers from various disciplines highlighted the generally poor if not blatantly false assumptions about real world energy use and economy underpinning the RCP 8.5 scenario
3/17
https://doi.org/10.1088/1748-9326/abcdd2 via @IOPscience
3/17
https://doi.org/10.1088/1748-9326/abcdd2 via @IOPscience
Next up...
AIR takes the view that hurricanes will increase in frequency and severity.
4/17
AIR takes the view that hurricanes will increase in frequency and severity.
4/17
The perspective is very in vogue among the media and politicians, but debated in scientific circles.
5/17
5/17
We are all waiting with bated breath for new IPCC reports to be released this year and next.
The attached shows a compilation of statements by the available 2013 IPCC report.
6/17
The attached shows a compilation of statements by the available 2013 IPCC report.
6/17
Basically, to take a clear cut position on what hurricanes will be doing differently in the future than in the past requires reflection on what your preferences are.
We wrote about this.
https://journals.sagepub.com/doi/abs/10.1177/0162243916671201#articleShareContainer
7/17
We wrote about this.
https://journals.sagepub.com/doi/abs/10.1177/0162243916671201#articleShareContainer
7/17
AIR points out the extensive uncertainties in predicting future hurricane behavior but in a way that suggests there is less uncertainty about future frequency and severity, and that's why they focus on those things in the report.
8/17
8/17
First, it's all epistemic uncertainty so, IMO, I don't think it's fair characterization. But, I am not a climate scientist.
It's worthwhile considering what climate scientists are saying. E.g. the AIR's referenced Kossin et al 2020.
9/17 https://www.pnas.org/content/117/22/11975
It's worthwhile considering what climate scientists are saying. E.g. the AIR's referenced Kossin et al 2020.
9/17 https://www.pnas.org/content/117/22/11975
The Kossin et al 2020 Significance statement concludes the following:
"The results should serve to increase confidence in projections of increased TC intensity under continued warming"
What does that confidence look like?
10/17
"The results should serve to increase confidence in projections of increased TC intensity under continued warming"
What does that confidence look like?
10/17
It's not the CI in the abstract above:
the major TC EP "increases by about 8% per decade, with a 95% CI of 2 to 15% per decade."
It's the CI in the article correction:
EP "increases by about 5% per decade, with a 95% CI of about 0.4 to 11% per decade. https://www.pnas.org/content/117/47/29990
the major TC EP "increases by about 8% per decade, with a 95% CI of 2 to 15% per decade."
It's the CI in the article correction:
EP "increases by about 5% per decade, with a 95% CI of about 0.4 to 11% per decade. https://www.pnas.org/content/117/47/29990
This doesn't shine as a beacon of certainty.
Also note that the Kossin et al. analysis is rooted in a hurricane dataset that they create (reference 7 in the first article)
12/17
Also note that the Kossin et al. analysis is rooted in a hurricane dataset that they create (reference 7 in the first article)
12/17
AIR gives focus to regionalization of impacts in the US
But, if there is low confidence in how climate change impacts will play out by basin, it seems reasonable that there is even lower confidence in how impacts play out within a basin for the subset of storms that make LF
13
But, if there is low confidence in how climate change impacts will play out by basin, it seems reasonable that there is even lower confidence in how impacts play out within a basin for the subset of storms that make LF
13
Finally, for those that believe history did not begin in 2010.
There is this gem of a graph in the report.
14/17
There is this gem of a graph in the report.
14/17
One might remember the 2006 RMS rollout of a near term model that changed estimates of their most intense storms by 36%
That model change happened to align remarkably with a dramatic contraction of capital
15/17
https://www.sbafla.com/method/portals/methodology/Meetings/2006/20060726_ClimatologicalSignalsFCHLPM-RMS.pdf
That model change happened to align remarkably with a dramatic contraction of capital
15/17
https://www.sbafla.com/method/portals/methodology/Meetings/2006/20060726_ClimatologicalSignalsFCHLPM-RMS.pdf
So, my two cents?
If you want to understand cat model changes you're best served by considering the state of the market.
The market moves faster than scientific knowledge. Science can be pieced together in many ways to tell many stories.
16/17
If you want to understand cat model changes you're best served by considering the state of the market.
The market moves faster than scientific knowledge. Science can be pieced together in many ways to tell many stories.
16/17
To decide what story to tell about future hurricanes, seems to be often determined by first deciding what 'reasonable' view and position in the market you want to take.
https://onlinelibrary.wiley.com/doi/abs/10.1111/rego.12255#.YA7xbgSczAM.twitter
17/ END
https://onlinelibrary.wiley.com/doi/abs/10.1111/rego.12255#.YA7xbgSczAM.twitter
17/ END
