SCIENCE · WHAT IF · PART 2 OF 3

The Year Earth Froze

October 2026

The short version

In Part 1, the sun went out and the average temperature fell below freezing within a week. Part 2 is the long freeze that follows. A month in, the fields are dead, food chains are collapsing from the bottom up, and cities are burning through fuel and food stores while the grid runs on whatever energy was already stored. Humanity retreats toward the equator — and downward, toward Earth's own heat. Meanwhile the oceans seal shut from the top down. But here is the physics nobody expects: ice insulates. Scientists estimate the frozen lid would keep the deep ocean liquid for hundreds of thousands of years. The surface becomes a freezer. The deep becomes a vault.

The fields went first

When photosynthesis stopped in Part 1, the countdown for the world's crops started with it. Most plants live only a few weeks on stored reserves, and in the cold and dark they would die on roughly that schedule — fields first, then the wild growth that livestock and wildlife depend on. With the base of the food chain gone, the collapse moves upward in order: herbivores starve, then everything that eats them. Scavengers would last longest, living off what the collapse leaves behind. None of this is speculation about biology; it is the structure of a food web with its foundation removed.

Power becomes a countdown

A modern city in the dark runs on inventory. Fuel stockpiles, food warehouses, water pressure, charged batteries — everything becomes a store being drawn down, because almost nothing is being replenished. The grid flickers not from damage but from arithmetic: power now means stored energy, and stored energy runs out. The survival logic that follows is the one experts name when they game out this scenario — retreat toward the equator's relative warmth, and toward places where heat comes from the Earth itself rather than the sky. Part 3 visits the strongest of those refuges.

The oceans seal shut — and that's the twist

As surface temperatures keep falling — estimates put the global average near minus 100 degrees Fahrenheit after a full year — the oceans freeze the only way they can: from the top down. A crust of ice spreads across the surface of the sea and thickens. It looks like the end of the ocean. Physically, it is closer to a lid being put on a pot. Ice is an insulator. The frozen skin traps the ocean's remaining heat beneath it, slowing the loss to a crawl. Caltech planetary scientist David Stevenson estimates the deepest water would not freeze for around a thousand years under that cap, and the oceans would not freeze solid for hundreds of thousands of years. The colder the surface gets, the safer the deep ocean becomes: liquid water, protected, in total darkness.

The takeaway

Most plants die within weeks of the light ending, and the food chain collapses from the bottom up — herbivores first, then their predators, with scavengers lasting longest.
City survival becomes an inventory problem: power means stored energy, and stored energy runs out.
The oceans freeze from the top down — but ice insulates, trapping the deep ocean's heat beneath a growing frozen lid.
Scientists estimate the oceans would not freeze solid for hundreds of thousands of years; the deep sea stays liquid under the ice.
The surface is becoming a freezer. The deep is becoming a vault.

So tell us — the freeze or the dark: which one breaks humanity first?

Sources

Popular Science — "If the Sun Went Out, How Long Would Life on Earth Survive?" (food-chain collapse, plant timelines, and the estimate that insulating ice would keep the oceans from freezing solid for hundreds of thousands of years)
Caltech Question of the Month — David Stevenson: ocean ice cap, deep water freezing only after ~1,000 years (estimate)
HowStuffWorks — "What if the sun disappeared?" (after a full year, an estimated −100°F average)

This is a speculative scenario, not a forecast. The mechanisms are established physics and ecology; every timeline and temperature figure is an expert estimate and is described as one.

Timelapse: "Time-lapse of navigation through Lemaire Channel, Antarctica" by Blagoj Klincharski, via Wikimedia Commons, CC BY 3.0.

The story so far: Part 1 — What If the Sun Went Out? Next: Part 3 — What Survives a Year Without the Sun? The surface is a frozen museum — but two kilometres down, something is still thriving, and it never needed the sun at all.