Ice Age Map FAQ

When was the last glacial maximum?

A widely used interval is about 26,500–19,000 BP. Different ice sheets reached their maximum extent at different times; the map’s 21,000 BP starting view is representative rather than universal.

References: Clark et al. (2009) — The Last Glacial Maximum

How much lower was sea level?

IPCC AR6 assesses LGM global mean sea level at about 125–134 m below present. Local relative sea level differed. This atlas displays a separately normalized Spratt–Lisiecki curve.

References: IPCC (2021) — AR6 Working Group I, Chapter 9, Table 9.6Spratt & Lisiecki (2016) — A Late Pleistocene sea level stack

Can I see how thick the ice was where I click?

Yes. Click a location and move the timeline. The panel displays the nearest PaleoMIST 1° grid node and 2,500-year snapshot. It is a model estimate, not a measurement at the exact pointer position.

References: Gowan (2019) — PaleoMIST reconstruction dataset, corrected April 2021 (CC BY 4.0)

Why can a white ice area show 0 m?

The overlay and inspector have different spatial representations: a simplified margin polygon and the nearest node of a 1° grid. They may disagree near an edge. Zero refers to grounded ice in that model cell, not necessarily every glacier within the surrounding region.

Was Beringia a bridge made of ice?

No. The land connection was exposed continental shelf during lower sea levels. Much of Beringia was unglaciated.

References: USGS — Geology of Bering Land Bridge National Preserve

Could people walk from Sunda to Australia?

The exposed Sunda and Sahul shelves remained separated by the seas and islands of Wallacea. A larger land area does not establish a continuous dry-land route.

References: Voris (2000) — Maps of Pleistocene sea levels in Southeast Asia: shorelines, river systems and time durationsSalles et al. (2024) — Physiography, foraging mobility, and the first peopling of Sahul

Did a single tsunami erase all Doggerland?

That is too simple. Research considers rising seas, local topography and the effects of the Storegga tsunami. The entire landscape should not be treated as having one proven destruction date.

References: Walker et al. (2020) — A great wave: the Storegga tsunami and the end of Doggerland?

Does “present” mean today?

For the chronology, BP is referenced to 1950. The zero view is the dataset’s present-day reference, not a live map of today’s ice or coast. The Holocene’s formal boundary uses a different reference: 11,700 years before 2000, approximately 11,650 BP.

References: International Commission on Stratigraphy — Holocene GSSPGowan (2019) — PaleoMIST reconstruction dataset, corrected April 2021 (CC BY 4.0)

Can this map prove migration routes or predict flooding?

No. It has no migration evidence layer, tsunami simulation or future climate scenario. A global elevation threshold cannot establish a local archaeological flooding date or future flood risk.