Climate Tipping Points

Collapse · Global Core

~1.5°C

Range 0.8-3°C · Unfolds over 10,000 years (1,000-15,000)

Holds enough ice to raise sea level by about 7 m. As it melts, its surface sinks into warmer air, which speeds the melting further.

GTP 2025 - likely tips around 1.5°C.

Collapse · Global Core

~1.5°C

Range 1-3°C · Unfolds over 2,000 years (500-13,000)

Much of it rests on bedrock below sea level, so warm ocean water melting it from beneath can set off a retreat that sustains itself.

GTP 2025 - likely tips around 1.5°C.

Abrupt thaw · Regional Impact

~1.5°C

Range 1-2.3°C · Unfolds over 200 years (100-300)

Ice-rich frozen ground collapsing and thawing abruptly, releasing carbon dioxide and methane that add to warming.

GTP 2025 - land permafrost likely tips around 1.5°C.

Abrupt loss · Regional Impact

~1.6°C

Range 1.5-1.7°C · Unfolds over 25 years

Winter ice in the Barents Sea can vanish abruptly as warm Atlantic water spreads north - the Arctic sea ice with the lowest tipping threshold.

Loss · Regional Impact

~2.0°C

Range 1.5-3°C · Unfolds over 200 years (50-1,000)

Once a glacier shrinks below a certain size it cannot regrow in the new climate - threatening the water supply of the people downstream.

GTP 2025 - likely tips around 2°C.

Collapse · Global Core

~3.0°C

Range 2-6°C · Unfolds over 2,000 years (500-10,000)

Low-lying basins of East Antarctica, such as Wilkes and Aurora, rest below sea level and are open to the same ocean melting as West Antarctica.

Collapse · Global Core

~4.0°C

Range 3-6°C · Unfolds over 50 years (10-300)

Widespread permafrost collapse across the far north, releasing about 125-250 billion tonnes of carbon and adding about 0.2-0.4°C of warming.

Collapse · Global Core

~6.3°C

Range 4.5-8.7°C · Unfolds over 20 years (10-100)

Year-round ice-free Arctic, only at very high warming. Summer sea ice is shrinking fast but is now judged not to be a tipping point - it shrinks steadily with warming instead.

Collapse · Global Core

~7.5°C

Range 5-10°C · Unfolds over more than 10,000 years

The largest mass of ice on Earth - at risk only at very high warming, over many thousands of years.

Convection collapse · Global Core

~1.5°C

Range 1.1-3.8°C · Unfolds over 10 years (5-50)

Deep mixing in the Labrador and Irminger Seas, south of Greenland, could switch off within a decade, cooling the North Atlantic region by around 3°C and shifting weather across Europe.

GTP 2025 - the subpolar gyre likely tips around 1.5°C.

Collapse · Global Core

~2.0°C

Range 1.4-8°C · Unfolds over 50 years (15-300)

The Atlantic's ocean conveyor. A collapse would bring much harsher winters to north-west Europe, shift tropical rain belts and disrupt monsoons.

GTP 2025 - at risk of collapse below 2°C, likely tipping around 2°C.

Greening · Regional Impact

~2.8°C

Range 2-3.5°C · Unfolds over 50 years (10-500)

A possible shift to a wetter, greener Sahel - a reminder that not every tipping point is a change for the worse, though the outcome is uncertain.

Die-off · Regional Impact

~1.2°C

Range 1-2°C · Unfolds over 10 years

Repeated marine heatwaves now bleach reefs faster than they can recover. The first part of the Earth system judged to be passing its tipping point.

GTP 2025 - central estimate 1.2°C (range 1-1.5°C), already crossed.

Dieback · Regional Impact

~2.0°C

Range 1.4-5°C · Unfolds over 100 years

Heat, drought, fire and pests could turn the southern edge of the great northern forests into open woodland and grassland.

GTP 2025 - boreal forests likely tip around 2°C.

Dieback · Global Core

~3.5°C

Range 2-6°C · Unfolds over 100 years (50-200)

Stores about 150-200 billion tonnes of carbon. Drought, fire and deforestation could turn much of it into degraded forest or savanna.

GTP 2025 - with deforestation, at risk below 2°C, the lower end of the range now 1.5°C.

Expansion · Regional Impact

~4.0°C

Range 1.5-7.2°C · Unfolds over 100 years

Forest spreading north into tundra. Dark trees absorb more sunlight than snow-covered tundra, adding to local warming.