Macroscope
RU

Arctic and Antarctic sea ice

Pick a country and switch indicators on: they all line up on one time axis. You can see what changed together, what came first, where official forecasts point and how far past ones missed. Under the chart: observations computed from what is on screen.

Arctic September sea ice extentmillion km²4.747 million km² 2025
46
Arctic March sea ice extentmillion km²14.119 million km² 2025
141516
Antarctic February sea ice extentmillion km²2.218 million km² 2025
234
Antarctic September sea ice extentmillion km²17.636 million km² 2025
171819
actual

Without JavaScript you see a ready view: World — Arctic September sea ice extent, Arctic March sea ice extent, Antarctic February sea ice extent, Antarctic September sea ice extent, 1979–2025. Every country has its own page that works without JavaScript (list below); the data is in the API.

How the indicators changed

  • Arctic September sea ice extent: 7.051 million km² in 1979 → 4.747 million km² in 2025 (−2.304 million km²). Peak: 7.667 million km² in 1980; the latest value is 38% lower. The trend broke around 2001 and 2008: −0.04 → −0.24 → −0.01 a year.
  • Arctic March sea ice extent: 16.342 million km² in 1979 → 14.119 million km² in 2025 (−2.223 million km²).
  • Antarctic February sea ice extent: 3.141 million km² in 1979 → 2.218 million km² in 2025 (−0.923 million km²). Peak: 3.895 million km² in 2008; the latest value is 43% lower. The trend broke around 2014: direction reversed (+0.01 → −0.12 a year).
  • Antarctic September sea ice extent: 18.196 million km² in 1979 → 17.636 million km² in 2025 (−0.56 million km²). Peak: 19.756 million km² in 2014; the latest value is 11% lower. The trend broke around 2014: direction reversed (+0.02 → −0.14 a year).

What changed at the same time

  • The fastest decline of "Arctic September sea ice extent" was in 1997–2007: 6.686 million km² → 4.267 million km². Over the same years: arctic March sea ice extent 15.467 million km² → 14.542 million km²; antarctic February sea ice extent 2.49 million km² → 2.905 million km²; antarctic September sea ice extent 18.596 million km² → 18.861 million km².
  • Over the last 10 years (2015–2025): arctic September sea ice extent 4.616 million km² → 4.747 million km²; arctic March sea ice extent 14.37 million km² → 14.119 million km²; antarctic February sea ice extent 3.799 million km² → 2.218 million km²; antarctic September sea ice extent 18.444 million km² → 17.636 million km².

How the indicators relate

  • Arctic September sea ice extent and arctic March sea ice extent (1979–2025, 47 years): levels are strongly related, in the same direction (r = 0.80); year-to-year changes show no reliable link (r = −0.14). This looks like a shared trend: both change over time, but not in step from year to year.
  • Arctic September sea ice extent and antarctic February sea ice extent (1979–2025, 47 years): levels are barely related (r = 0.14); year-to-year changes show no reliable link (r = 0.02).
  • Arctic September sea ice extent and antarctic September sea ice extent (1979–2025, 47 years): levels are barely related (r = 0.02); year-to-year changes show no reliable link (r = 0.11).

Moving together in time does not prove a cause: incomes, cities, education and the era itself act on many indicators at once. These observations suggest where to look, not what causes what.

Key findings

  • UN projection of 2024: in 33 of 42 countries that already report 2024–2025 data, births are below the medium variant; in 8, below the lower bound of the 95% interval.
  • Japan: 709k births in 2024 (including children of foreign nationals). Even the latest official projection (IPSS 2023, medium) expected this level only in 2042, 18 years later. An earlier projection (IPSS 2002, medium) expected it in 2045.
  • Taiwan: 108k births in 2025. Even the latest official projection (NDC 2024, medium) expected this level only in 2036, 11 years later. An earlier projection (NDC 2016, medium) expected it in 2057.
  • China: 7.92M births in 2025. Even the latest official projection (UN WPP 2024, medium) expected this level only in 2050, 25 years later. An earlier projection (UN WPP 2022, medium) expected it in 2054.
  • United States: 1.60 children per woman in 2024. The SSA 2015 projection assumed 2.04 for that year, a gap of −22%.
  • South Korea: 0.80 children per woman in 2025. Projections made before 2020 expected 1.00–1.38 for 2025, while the 2021 and 2023 projections turned out lower than reality: fertility rose slightly in 2024–2025. Errors go both ways.
  • World: 67% of people live in countries with fertility below replacement (2.1), 31% below 1.5. World population is still growing: the UN expects a peak of about 10.3B in 2084.

All forecast-vs-actual checks →

How it works

  • A source for every number. Links go to the primary publication: the statistical office, the UN, the projection archive.
  • Forecast against fact. Next to a figure: what official projections expected for it and how far reality departed.
  • Association is not cause. Moving together in time suggests where to look; the observations under the chart always say so and check a link not only in levels but also in year-to-year changes.
  • Open data. Every table is available as CSV and JSON to check, recompute and reuse.
  • For programs and AI agents. The same data through an API and an MCP server, no page scraping: how to connect.

Data as of 7 October 2026

Country pages

Each country has a page that works without JavaScript: key indicators, observations, past UN and IMF forecasts against actual data, every series with source links. Countries →