Some new models from Los Alamos that go further than the RCPs in quantifying climate change.
A new computer model of accumulated carbon emissions predicts the likelihood of crossing several dangerous climate change thresholds. These include global temperature rise sufficient to lose the Greenland Ice Sheet and generate seven meters of long-term sea level rise, or tropical region warming to a level that is deadly to humans and other mammals.
Read more at: https://phys.org/news/2017-02-likelihood-dangerous-climate-thresholds.html#jCp
http://iopscience.iop.org/article/10.1088/1748-9326/10/11/115007/meta
- models, (which we know are inaccurate) see Jason Box.
- mathematical extrapolation (melt rate + doubling period of melt rate). Not sure if this method is really accurate, it gives impressive results despite it seems logical.
- Comparative estimation as in James Hansen research paper which compares the Eemian period to our actual climate. A really interesting research to read.
On my You Yuube channel, I gathered some of his videos in a playlist : https://www.youtube.com/playlist?list=PLNE7MxZHxhX8K76DCZStfLHCP8_ZT0xEY
Do you have a cite for predictions that are half or less?
Sea level rise estimates vary a lot because there are a few ways to estimate them.
This documentary shows (amongst other things) how much Greenland melted during the Eemian.
See James Hansen research in which he compares present day climate to the Eemian, his SLR estimates rocked the climate community.
How fast this will happen is debated.
If you want to do a simple math estimate, Greenland's melt rate is about 260 Gt/year and the melt rate used to double every 7'ish years but take note that Greenland's melt rate doubled from 2011 to 2014. Yes there is a research about that too.
It's this one?
http://www.atmos-chem-phys.net/16/3761/2016/acp-16-3761-2016.html
And please note, again, The TFA abstract is talking about 7m rise if the Greenland ice sheet melted, regardless of how long it took. It's not so much a prediction of sea level rise by a fixed date such as 2100.
http://www.atmos-chem-phys.net/16/3761/2016/acp-16-3761-2016.pdf