| ▲ | garrettdreyfus 4 days ago | ||||||||||||||||||||||
The study you cite is talking about sea level rise since 1900 which is a very different story. The IPCC section “9.6.1.1 Global Mean Sea Level Change Budget in the Pre-satellite Era” says Since SROCC, a new ocean heat content reconstruction (Section 2.3.3.1; Zanna et al., 2019) has allowed global thermosteric sea level change to be estimated over the 20th century. As a result, the sea level budget for the 20th century can now be assessed for the first time. For the periods 1901–1990 and 1901–2018, the assessed very likely range for the sum of components is found to be consistent with the assessed very likely range of observed GMSL change (medium confidence), in agreement with Frederikse et al. (2020b; Table 9.5). This represents a major step forward in the understanding of observed GMSL change over the 20th century, which is dominated by glacier (52%) and Greenland Ice Sheet mass loss (29%) and the effect of ocean thermal expansion (32%), with a negative contribution from the LWS change (–14%). While the combined mass loss for Greenland and glaciers is consistent with SROCC, updates in the underlying datasets lead to differences in partitioning of the mass loss.” Edit: by a different story I mean a different story from what is the leading driver of sea level rise. Sea level rise from ice melt was larger since 1900 because sea level rise in general was less fast back then and global mean temperature rise was much smaller so thermosteric sea level rise played less of a role. Thermosteric sea level rise is larger than ground water factors, both will be eclipsed by ice melt in the upcoming century. I would note the authors pointedly do not call it the leading driver of sea level rise. | |||||||||||||||||||||||
| ▲ | perching_aix 4 days ago | parent | next [-] | ||||||||||||||||||||||
So let me get this straight: - sea level is formally referred to as Global Mean Sea Level (GMSL) - its change is segmented into two subcategories in literature(?), mass-driven (e.g. ice melting?, freshwater runoff?, freshwater water cycle stuff?) and non-mass-driven (e.g. thermal expansion?) - freshwater loss from land was found to be at present the lead driver of the mass-driven change as per the paper (over what timeframe?) - title says it's the primary driver for GMSL change overall, which this alone doesn't support (i.e. the title is a lie) - @ornel (the person posting) points to another study that claims mass-driven change is the leading change, hence the title [0, this doesn't pass my smell test but i see the logic] - you point out that that's glossing over that that other study is counting from 1900, but if one shrunk the evaluation window, the non-mass-driven causes would be the drivers now [1, this doesn't pass my smell test either, but i see the logic here as well] The latter point then begs the question though, what is the time window in this case then, and how stable that result is? What would be an "appropriate" time window to choose, and how would one derive that? Regarding my non-passing smell tests, imagine the following scenario for some event: - category A: 51% of the total - cause A1: 26% of the total - cause A2: 25% of the total - category B: 49% of the total - cause B1: 27% of the total - cause B2: 22% of the total In this case, category A will be the lead contributor, but individually none of its contributing causes will be, addressing [0]. The causes will be ordered like so instead: B1 > A1 > A2 > B2. More elaborate variations are possible of course. For [1], you can imagine the same scenario just in reverse. Did I get all this right? | |||||||||||||||||||||||
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| ▲ | garrettdreyfus 4 days ago | parent | prev [-] | ||||||||||||||||||||||
See table 9.5 | |||||||||||||||||||||||
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