Apocalypse has a preferred unit, and it is not the centimetre. When Al Gore stood in front of a drowning Florida and talked about twenty feet, he was not offering a tide gauge. He was offering a sermon. West Antarctica "goes," Greenland "goes," the map of the low countries becomes an aquarium, a hundred million people walk. Two decades later the Southern ice has not obliged the slide. A recent study, as reported, finds that glacier melt from the Antarctic Ice Sheet added about three-quarters of a centimetre to global sea level across the period 1992 to 2020, less than a centimetre in thirty years. That is not the film. It is a number. Politics built on the film has never forgiven the number for being small.
The distinction matters because ice is not one object. Sea ice is not the ice sheet. The Peninsula is not East Antarctica. A glacier thinning at the coast is not the continent sliding into the ocean before the next election. Gore's imagery collapsed those categories into a single collapse. If "this were to go," he said of Antarctic ice, seas would rise twenty feet; Greenland could do the same. The grammar is conditional. The pictures were not. Audiences remember the submerged street, not the century-scale caveat scientists attach when they talk about a complete deglaciation that would take far longer than a human career. Observed global sea level since the late nineteenth century is on the order of inches, not storeys. Thermal expansion of warming water and melt from Greenland and mountain glaciers do real work. Antarctica's measured contribution over a generation, on the figure now being circulated, is a fraction of a centimetre per year. You can call that "alarming" in a paper abstract. You cannot call it Manhattan under the tide.
The same study, as summarised, finds a rising surface mass balance over decades in the western Peninsula glaciers it tracks, and elevation change that is stable to slightly positive. Snow and ice accumulating on land is water that is not, for now, in the harbour. That does not freeze the climate debate into a victory lap. West Antarctic outlets can lose ice to the ocean even while other sectors gain. Dynamic instability is a research question, not a press-conference certainty. What it does do is puncture the habit of treating every calving photograph as confirmation of the 2006 storyboard. A calving front is how ice sheets live. A centimetre in thirty years is how this one, in this interval, has shown up in the global budget.
Alarmism needed a timetable. Arctic summer sea ice would be gone "in five to seven years." Glacier National Park would need a new name. The window to act would slam in 2016. The ice did not vanish on cue. The park still has ice. Emissions rose anyway. The preacher's defence is always that the direction was right and only the clock was poetry. Direction without magnitude is how you justify any policy. If the catastrophe is always next decade, no observed slowness can ever count as evidence. The model is unfalsifiable by design: centimetres are "locked in," metres are still coming, and anyone who reads the tide gauge is a denier.
A serious climate argument can survive without the drowning-map. Greenhouse gases warm. Ice responds, unevenly. Coasts need planning measured in the units that exist, tens of centimetres over a century on central estimates, with tails that are worse if ice sheets run faster than the middle of the distribution. That is engineering and energy policy. It is not a licence to speak as if the West Antarctic sheet were a trapdoor under Miami. The cruelty of the old presentation is that it trained a generation to experience ordinary increment as betrayal. When the increment arrives as 0.74 centimetres from a slice of Antarctic glacier melt, the response is not to adjust the rhetoric. It is to announce that 0.74 is still a crisis because the alternative would be to admit the sermon overshot the ice.
Gore did not invent concern for the poles. He popularised a style: total melt as a visual, near-term politics as the implied deadline, dissent as moral failure. The ice has been a poor actor in that production. It melts here, thickens there, and adds to the ocean at a pace that would bore a disaster movie. If the next thirty years look like the last, the map of Florida will still be Florida. The people who sold twenty feet will still have speaking fees. The difference between those two facts is the difference between a civilisation that can count and a civilisation that prefers a flood that never quite arrives.