|Ports, ice caps, and Sea Level R us|
That departure was due to the incessant underestimations the IPCC's linear SLR models produced, even though other parts of their projections had been spot on (New Climate Catastrophe Policy: Triage - 12, The Evolution of Models, 2, 3, 4).
The models need to implement the notion of acceleration, in place of linear growth, when projecting future SLR.
The reasons have been explained by Hansen, Sato (2012) in an update, where, not having the use of Cryosat-2 satellite data, they wrote:
The increasing Greenland mass loss ... can be fit just as well by exponentially increasing annual mass loss, a behavior that Hansen (2005, 2007) argues could occur because of multiple amplifying feedbacks as an ice sheet begins to disintegrate. A 10-year doubling time would lead to 1 meter sea level rise by 2067 ... 2045 ... for 5-year doubling time and 2055 ... for a 7-year doubling time.(Hansen, Ice Melt, emphasis added). The absence of Cryosat-2 data has now come to an end.
Ice volume loss measurement, as detected by Cryosat-2, indicates that a doubling of ice loss took place in 5 years (2009-2013).
Thus, my SLR calculation was not conceptually excluded by Hansen, Sato in the quote of their paper above (see What Do You Mean - World Civilization? - 2).
I also selected a 3 ft. (~1 meter) SLR as a catastrophic point to watch, and prepare for (New Climate Catastrophe Policy: Triage - 12), and hypothesized about when it could take place depending on the rate of acceleration (The Evolution of Models, 2, 3, 4).
Where I have differed was not to focus on "doubling" per se, but rather on rate of acceleration:
Notice that the ~3 ft. SLR takes place circa 2042 in these projected 14.87% -> 4.37% and 14.87% -> 4.08% acceleration details, rather than taking place circa 2100 as the IPCC projection expects.(Will This Float Your Boat - 5). This (2042) is quite close to "2045 ... for 5-year doubling time" as written by Hansen, Sato (2012) and quoted above.
What happens after 2042 in the graph indicates catastrophic SLR, if the current melt acceleration of 14.87% continues for perhaps another decade or so, as it has since 2009 until now.
Like I said though, it should decrease naturally as the "low hanging fruit" ice near the coasts of Greenland and W. Antarctica melt away, leaving only the more stable inland ice.
Remember how touchy Americans are about their ports (Mohammed Has Dick Cheney Eyes).
The danger to all nations including American ports, according to these projections, is SLR of ~1 meter or ~3 ft. (Ports & Harbors).
I am satisfied that my C++ SLR modelling program is robust and flexible enough to go with the flow of data being provided by Cryosat-2 (volume measurements) and GRACE (gravity measurements).
And there are only 1,176 lines of code, including comments (some modelling programs have millions of lines of code).
The .sql and .dat flatfile database builders add 40 & 65 non-code lines to the total, for a grand total of 1,281 lines.
The next post in this series is here, the previous post in this series is here.
Dust thou comprehend?