The warmer Eemian climate is linked to greater northern hemisphere insolation as a result of an orbit with greater eccentricity and precession that placed the northern hemisphere solstice close to perihelion. Below, I'm comparing Earth's orbit at the Eemian with Earth's current orbit. These diagrams are for illustration; they are not to scale. I created them using my orbit viewer.
A potential sea level rise of up to 9 meters, suggested by Kopp et al, is disturbing, especially because the author's don't rule out periods of a higher rate of change that the 62-90 cm per century. For me, the observation that CO2 levels didn't rise beyond the Holocene's pre-industrial levels is intriguing. CO2 and methane from a warming biosphere is part of a worst case global warming scenario. I wonder if the Eemian shows that we have a 2-4 C grace period before this feedback kicks in.