Sea & Ice
The warming ocean, the melting ice on land and sea, and how much of the sea's rise each adds…
Warming water expands and melting land ice drains into the sea, and together they raise it. This page follows each part: sea temperatures and marine heatwaves, the heat stored in the ocean, Arctic and Antarctic sea ice, the Greenland and Antarctic ice sheets, the world's mountain glaciers and sea level since 1880, and how much of the rise each adds.
Current State
Ocean warmth, ice and sea level against their records. Melting land ice raises the sea. Any lost ice, sea ice included, exposes darker ground or water that absorbs more sunlight, the .
Ocean SurfaceGlobal Ocean SurfaceSep 2026
+0.97°CRecord
Warmest September on Record
Sea Regions0 of 0 in a Heatwave
Baselines: ocean surface 1961-1990, ocean heat 1955-2006, map 1991-2020; sea ice "normal" is NSIDC's 1981-2010 median. "Now" rates are the last 10 years (362 Gt of ice = 1 mm of sea). Glaciers exclude Greenland's and Antarctica's, counted with the ice sheets; a glacier year ends with each summer's melt.
Sources: NOAA NCEI (ocean surface, NOAAGlobalTemp) · NOAA NCEI Ocean Heat Content · NOAA Laboratory for Satellite Altimetry and CSIRO (Church & White 2011) · NASA JPL GRACE/GRACE-FO · WGMS (Dussaillant et al. 2025; regions GTN-G) · NSIDC Sea Ice Index · NOAA OISST (map).
The Trends
The six measures above, decade by decade - each bar a decade's average, in the same places as the boxes.
Ocean Surface vs the 1980s (°C)
Sea Level Rise (mm/yr)
The 2020s so far. Ocean heat is against 1955-2006. Sea level is the rate over 10-year spans since satellites began (1993); ice sheets from 2002 (GRACE); glaciers outside the ice sheets.
Sources: NOAA NCEI (ocean surface) · NOAA NCEI Ocean Heat Content · NOAA Laboratory for Satellite Altimetry · NASA JPL GRACE/GRACE-FO · WGMS (Dussaillant et al. 2025) · NSIDC Sea Ice Index.
The Ocean
Sea TemperaturesSea Temperatures by Region
Each region’s last year against its marine heatwave threshold, and every year since 1982 - vs the 1991-2020 average for the day.
- North AtlanticAMOC Tracker
- The wider North Atlantic, from the tropics to the latitude of Scotland. It broke its records through 2023-24 and has stayed near them since - its warmth feeds hurricanes and Europe's weather, and is carried north by the AMOC.
- North Sea & UK WatersNAO Tracker
- The shallow seas around the UK and north-west Europe. Being shallow, they heat and cool quickly with the weather, so marine heatwaves here follow settled, sunny spells - as in June 2023 - and are steered by the North Atlantic Oscillation.
- Subpolar North Atlantic (Cold Blob)AMOC Tracker
- The patch of ocean south of Greenland and Iceland that has cooled by up to about 1°C since 1900 while almost everywhere else warmed - the "cold blob" or "warming hole". It is widely read as a sign the AMOC is weakening, as meltwater freshens the water that should sink and carry heat north.
- MediterraneanEurope Climate Update
- An almost enclosed sea that is warming faster than the global ocean. Summer marine heatwaves now come most years, bleaching its corals and seagrass, and its warmth feeds the intense autumn storms and floods around its coasts.
- CaribbeanCoral Bleaching Tracker
- Warm, shallow water with the Atlantic's main coral reefs. Heat stress here bleached reefs across the region in 2023-24, and its warmth fuels the hurricanes that track through it.
- Gulf of MexicoExtreme Weather
- One of the warmest seas on Earth by late summer. Its deep warm water can turn a passing storm into a major hurricane within a day - rapid intensification - before it reaches the US Gulf Coast.
- Tropical Pacific (Niño 3.4)ENSO Tracker
- The central equatorial Pacific box NOAA uses to classify El Niño and La Niña. When it runs 0.5°C or more above normal for months, El Niño is under way - shifting rainfall, heat and storms around the world.
- Eastern Pacific (Niño 1+2)ENSO Tracker
- The eastern end of the equatorial Pacific, off Peru and Ecuador. It often warms first in an El Niño - a "coastal El Niño" can bring floods to Peru while the central Pacific is still near normal - and it drives the region's fisheries.
- Baja California & Gulf of CaliforniaENSO Tracker
- Both coasts of Baja California and the Gulf of California. Cold water welling up along the coast usually keeps it cool; when that upwelling weakens - often as the eastern Pacific warms in an El Niño - the sea here heats fast, and marine heatwaves hit its kelp forests, fisheries and the Gulf's rich sea life.
- North PacificPDO - ENSO Tracker
- The wide North Pacific, home to "the Blob" - the marine heatwave of 2014-16 that killed seabirds and closed fisheries. Large heatwaves here have become more frequent, and the Pacific Decadal Oscillation sets its slow swings.
- Coral Sea & Great Barrier ReefCoral Bleaching Tracker
- The Great Barrier Reef and the Coral Sea off north-east Australia. Its summer heat (December to March) decides each year's bleaching - the reef has been through six mass bleachings since 2016.
- Tasman SeaNew Zealand Climate Update
- The sea between south-east Australia and New Zealand, warming several times faster than the global ocean as the East Australian Current pushes further south. Its marine heatwaves are among the longest recorded - 251 days in 2015-16 - and hit Tasmania's kelp forests, oyster and salmon farms.
- Southern Ocean Fronts
- The band of fronts from south of Africa to south-west of Australia, where the Agulhas Return Current meets the Antarctic Circumpolar Current. Eddies here make a string of hot and cold spots, and the fronts are moving south as the Southern Ocean warms - it takes up more of the extra heat and carbon than any other ocean.
- Tropical Indian OceanIOD Tracker
- The tropical Indian Ocean, warming faster than any other tropical ocean. Its east-west tilt, the Indian Ocean Dipole, decides drought or flood from East Africa to Australia, and El Niño warms it a few months later.
- Bay of BengalIOD Tracker
- The warm bay between India and Myanmar, which powers the region's monsoon rains and its deadliest cyclones. Warmer water lets cyclones strengthen faster before they reach some of the world's most crowded coasts.
- Maldives & LakshadweepCoral Bleaching Tracker
- The atolls of the Maldives and Lakshadweep, in the central Indian Ocean. Their reefs bleach in March to July, when El Niño's delayed warming usually arrives - so warmth here in the autumn is an early warning for next spring.
- Red SeaCoral Bleaching Tracker
- A narrow, very warm and salty sea between Africa and Arabia. Its northern reefs are unusually heat-tolerant - a possible refuge for corals - while those in the south bleach more often.
- South China SeaCoral Bleaching Tracker
- A large, partly enclosed sea between southern China, Vietnam and the Philippines, with extensive reefs. Its warmth strengthens the typhoons that cross it, and marine heatwaves here have grown longer and stronger.
- Siberian Arctic Seas
- The Kara, Laptev and East Siberian seas along Russia's Arctic coast. Where sea ice has melted away, the open water soaks up summer sunshine the ice would have reflected and stays well above its usual near-freezing temperature into the autumn - Arctic amplification, which gives these seas some of the largest anomalies on Earth.
- Barents Sea
- The Arctic sea north of Norway and Russia, where warm Atlantic water flows in. As that inflow strengthens, the sea's ice is retreating north - the "Atlantification" of the Arctic - and the Barents is warming faster than almost anywhere on Earth. Under ice the surface stays near freezing, so its anomalies show in the open-water months.
- Chukchi & Beaufort Seas
- The seas north of Alaska and Chukotka. Ice that once lasted all summer now clears most Septembers, and the open water soaks up sunlight and warms - which delays the autumn freeze in turn. Under ice the surface stays near freezing, so its anomalies show in the open-water months.
- Hudson Bay
- The inland sea in northern Canada, frozen over for most of the year, so its anomalies show in the open-water months. A warm autumn delays the freeze-up - and the polar bears of western Hudson Bay, which hunt seals from the ice, wait longer on land.
A marine heatwave is 5 or more days above the warmest 10% for the time of year (the 1991-2020 90th percentile; Hobday et al. 2016), here for each region’s average. Categories - moderate, strong, severe, extreme - are multiples of that threshold. The baseline is fixed, so the warming trend itself now carries many regions over it - that is part of the story, not a quirk. Source: NOAA OISST v2.1 (Huang et al. 2021).
Global Ocean Temperature
Global Ocean · Absolute Temperature
Ocean covers ~71% of Earth's surface, so its temperature moves the global average more than any other single factor.
Source: NOAA Climate at a Glance
Ocean Heat Content
The heat stored in the upper ocean, where about 90% of the extra heat from greenhouse gases ends up.
Source: NOAA NCEI Global Ocean Heat Content (World Ocean Database; Levitus et al. 2012, updated)
Sea Ice
Global Sea Ice Extent
Arctic + Antarctic Combined · Absolute Extent
Last 60 months. Thick line shows 12-month rolling average – Arctic loss exceeds Antarctic variability.
Source: NSIDC via global-warming.org
Arctic Sea Ice - 1978–2026
One line per year since satellite records began. 2026 is highlighted; the lowest Sep on record (2012) is picked out in red.
Record low for Sep: Sep 2012 at 3.57 M km² (million km²). Source: NSIDC Sea Ice Index v4 · monthly averages · against the 1981–2010 median.
Antarctic Sea Ice - 1978–2026
One line per year since satellite records began. 2026 is highlighted; the lowest Sep on record (2023) is picked out in red.
Record low for Sep: Sep 2023 at 16.89 M km² (million km²). Source: NSIDC Sea Ice Index v4 · monthly averages · against the 1981–2010 median.
Polar Ice Extent
Each September, then today's ice edge (navy) against the 1981-2010 median for the date (dashed orange).
Sources: NSIDC Sea Ice Index v4 (September extent outlines, daily extent grids for today's edge, the 1981-2010 median edge) · NOAA NCEI (global and ocean temperature) · NOAA satellite altimetry (sea level)
Warm Seas, Less Ice
Each dot is a year: a polar sea's surface temperature against its sea ice.
Sources: NOAA OISST v2.1 · NSIDC Sea Ice Index
Sea Ice - Long-Term Trend
Yearly average extent, 1979 onwards (M km²)
The Arctic has lost ice steadily since 1979; the Antarctic held steady, even grew slightly, until 2015, then fell to record lows as the upper Southern Ocean warmed - so the total has dropped since 2016. Arctic ice also reflects sunlight back to space, so its loss speeds warming. Source: NSIDC Sea Ice Index v4 (average of each complete year's monthly extents).
Land Ice
Ice Sheets
Greenland and Antarctica, weighed from orbit each month by the GRACE satellites - the ice lost since 2002.
Source: NASA JPL GRACE/GRACE-FO Mascons (Wiese et al. 2022)
Mountain Glaciers
The world's glaciers outside Greenland and Antarctica, and the ice they lose each year since 1976.
Glaciers hold far less ice than the ice sheets but now add about as much to the sea, and their meltwater feeds dry-season rivers from the Andes to Asia. Years run to the end of each summer's melt. Glaciers around Greenland and Antarctica count with the ice sheets; the sub-Antarctic islands are in.
Source: World Glacier Monitoring Service annual mass-change estimates (Dussaillant et al. 2025); regions GTN-G. 1 gigatonne = 1 billion tonnes.
Sea Level
Sea Level Since 1880
The global mean: tide gauges to 1992, then satellites, against 1993.
Your Coast Isn't Average
What a coast feels is relative sea level - the ocean's rise plus the land's own movement. Sinking deltas and cities can see several times the global rate; land still rebounding from the ice age can see the sea fall.
Grand Isle, Louisiana
+9mm/yr
Delta land sinking as sediment compacts and oil, gas and water are pumped out - nearly three times the global rate. [NOAA]
North Jakarta
~5cm/yr
Groundwater pumping: North Jakarta averaged about 5 cm a year in 2019-20 by satellite, some districts faster - more than ten times the sea's rise. [Sentinel-1 study]
Juneau, Alaska
-13.5mm/yr
Land still rising after its glaciers thinned and the weight came off - so the sea there falls, for now. [NOAA]
Look up a coast: NOAA sea level trends (tide gauges worldwide) · NASA's IPCC projection tool (to 2150) · Climate Central flood maps · NOAA high-tide flooding outlook (US).
Source: Church & White 2011 (CSIRO tide-gauge reconstruction, 1880-2009) · NOAA Laboratory for Satellite Altimetry (1993-present). Rates are least-squares trends.
Where the Rise Comes From
Each source of sea level rise measured on its own, then added up - since 2005, when floats and satellites began measuring every part.
Sources: NOAA NCEI (thermosteric sea level) · NASA JPL GRACE/GRACE-FO (ice sheets) · WGMS (glaciers outside the ice sheets) · NOAA satellite altimetry
How It Connects
Everything Moves Together
Carbon dioxide, global and ocean temperature, Arctic ice and sea level since 1950, one above the other. Complete years.
How Closely Each Link Has Moved Together
CO₂ and Global Temperature
r = 0.97
68 years
Global Temperature and Arctic Ice
r = -0.91
47 years
r runs from -1 to +1: near ±1, two series rose and fell together year by year (minus: one fell as the other rose). Long shared trends push r up on their own, so it shows how closely they moved, not why - the physics is the link: more CO₂ traps heat, a warmer ocean expands and melts ice, and meltwater and expansion raise the sea.
Sources: NOAA GML (CO₂, Mauna Loa) · NOAA NCEI (global and ocean temperature, rebased to 1961-90) · NSIDC Sea Ice Index · Church & White 2011 and NOAA satellite altimetry (sea level).