Which estimate do we believe? Well considering that we have consistently seen previous estimates revised upwards to reflect the increased rate of melt/warming. I'd err on the side of panic if I were you.
It was during the Bush/Cheney corporate coup that Antarctica was still being described as being immune to global warming for another thousand years. A decade later not only has it been proven irrefutably (by satellite laser measurements) that the interior of the continent experiences melt each summer (once thought impossible for centuries yet to come) but now we are being warned of a possible catastrophic melt caused by the collapse of the surrounding ring of ice shelves that keep the interior ice cap from starting to slide down into the sea. Antarctic glaciers weren't supposed to slide, they were miles high and believed 'eternally' frozen. Well oops man, they ain't no more.
Every year there is melt water deep into the continent where no standing water has any place being. Think of an ice cube freshly taken from the freezer. Its surface is dry to the touch. Give it a few minutes exposure to room temperature and the surface becomes wet as it melts. That is now happening to Antarctica every summer.
Suddenly (a decade or so is like instantly in geologic terms) Antarctica can melt... and melt fast! Not all of it at once but mostly that ring of floating ice surrounding the land. When that goes the interior ice starts sliding into the sea like it does these days in Greenland.
By 2050 - a possibility of 10 feet sea level rise? That's only thirty five years for a helluva bad tourist season at the beach. Um? The new beach much further inland. We call that catastrophe.
My question is when that happens... then what?
Sorry kiddies we all f'd up as a species. I won't be there to see it but in 35 years ... the catastrophes will just be beginning. Sorry 'bout that kids. Looks like recycling wasn't enough.