What Happened
- January 2026 was the fifth warmest January on record globally, measuring 1.47°C above the pre-industrial average (1850-1900 baseline), according to data from the Copernicus Climate Change Service (C3S) of the European Centre for Medium-Range Weather Forecasts (ECMWF).
- Despite global warmth, Europe recorded its coldest January since 2010 (average land temperature -2.34°C), while North America and Siberia also experienced heavy snowfall and freezing conditions — a paradox driven by a destabilised Arctic jet stream.
- The Southern Hemisphere simultaneously faced extreme heat: Australia, Chile, and Argentina experienced heatwaves and destructive wildfires.
- Average sea surface temperatures (SSTs) between 60°S-60°N reached the fourth highest on record; portions of the North Atlantic recorded historic highs.
- Sea ice extent was 6% below normal — the third-lowest extent for this period.
- Southern Africa experienced catastrophic flooding that killed approximately 200 people.
- January 2026's temperature of 1.47°C above pre-industrial levels marks a 0.28°C decrease from the record-breaking January 2025 (1.75°C), but remains well above the Paris Agreement's 1.5°C long-term average threshold.
Static Topic Bridges
Global Temperature Records and the Pre-Industrial Baseline
Global mean temperature anomalies are measured against a pre-industrial baseline period (1850-1900), before significant human-caused warming began. This baseline is the reference point for the Paris Agreement's temperature targets.
- ERA5 dataset: Produced by ECMWF's Copernicus Climate Change Service; provides continuous global reanalysis of weather data from 1940 to present. Along with NASA GISS and NOAA GlobalTemp, ERA5 is one of the three authoritative global temperature datasets.
- Pre-industrial baseline (1850-1900): Chosen because reliable instrumental records exist from this period and industrial greenhouse gas emissions were minimal.
- Anomaly calculation: Monthly temperature anomaly = observed average minus the average for the same period in the reference period (typically 1991-2020 or 1850-1900 depending on context).
- Paris Agreement targets: Keep global average temperature rise "well below" 2°C above pre-industrial levels, pursuing efforts to limit to 1.5°C (Article 2).
- 2023 and 2024 were the first and second warmest years on record respectively; 2024 was the first calendar year to exceed the 1.5°C threshold on annual average.
Connection to this news: January 2026's 1.47°C anomaly above pre-industrial levels is not a one-month threshold breach of the Paris target (which refers to long-term averages), but the sustained run of such monthly readings underscores that long-term warming is approaching dangerous territory.
Arctic Jet Stream: Structure, Disruption and Extreme Weather
The Arctic (Polar) jet stream is a fast-moving band of westerly winds circling the Northern Hemisphere at 8-12 km altitude. Its stability determines the distribution of cold and warm air across North America, Europe, and Asia.
- The jet stream is maintained by the temperature differential between Arctic cold air and mid-latitude warm air. As the Arctic warms faster than the tropics (Arctic amplification — ~4× the global average rate), this differential weakens.
- A weakened jet stream becomes "wavy" (high amplitude Rossby waves) — allowing lobes of cold Arctic air to dip far southward (polar vortex disruption) while warm air penetrates into the Arctic.
- This produces simultaneous cold snaps in Europe/North America and anomalous warming in the Arctic — the exact pattern observed in January 2026.
- Sudden Stratospheric Warming (SSW): An abrupt warming of the polar stratosphere can displace the polar vortex, sending frigid air into mid-latitudes. SSW events have been linked to extreme cold outbreaks in Europe and India's western Himalayan states.
- The phenomenon explains the apparent paradox of "global warming causes extreme winters" — a misleading framing that obscures the underlying dynamics.
Connection to this news: The article explicitly attributes Europe's coldest January since 2010 to a "wavy and unstable Arctic jet stream" channelling cold air southward — a textbook example of polar vortex disruption driven by Arctic amplification.
Sea Ice Extent and Ocean Heat: Indicators of Accelerating Change
Sea ice extent and sea surface temperatures (SSTs) are among the most sensitive and policy-relevant indicators of climate change. Both are measured routinely by satellite and used in global climate assessments.
- Arctic sea ice extent: Measured by the National Snow and Ice Data Center (NSIDC) in the US. The September minimum and March maximum are the key benchmarks. Arctic sea ice has declined by ~13% per decade since 1979 (September minimum).
- Sea ice reflects ~80% of incoming solar radiation (high albedo). As it melts, darker ocean water absorbs ~94%, amplifying warming — the ice-albedo feedback loop.
- Antarctic sea ice has shown more complex variability; 2023-24 saw unprecedented Antarctic sea ice loss.
- Elevated SSTs increase evaporation, fuel cyclones/hurricanes, and alter the thermohaline circulation (global ocean conveyor belt). High North Atlantic SSTs — as recorded in January 2026 — are associated with changes in the Atlantic Meridional Overturning Circulation (AMOC).
- AMOC weakening is among the most concerning potential tipping points: it could drastically reduce temperatures in Europe and shift monsoon patterns globally.
Connection to this news: January 2026's sea ice extent at 6% below normal (third-lowest for this period) and record North Atlantic SSTs are not isolated data points — they are part of a pattern of accelerating ocean-cryosphere change with global implications.
Key Facts & Data
- January 2026: 1.47°C above pre-industrial (1850-1900) average — fifth warmest January on record.
- Previous record: January 2025 at 1.75°C above pre-industrial baseline.
- Europe January 2026: coldest since 2010, average land temperature -2.34°C.
- Southern Hemisphere: heatwaves + wildfires in Australia, Chile, Argentina simultaneously.
- SSTs (60°S-60°N): fourth highest average on record in January 2026.
- Sea ice extent: 6% below normal — third-lowest for this period.
- Southern Africa flooding: ~200 deaths.
- Paris Agreement Article 2: limit warming to well below 2°C, pursue 1.5°C above pre-industrial levels (long-term average, not any single month).
- Arctic amplification: Arctic warming ~4× faster than global average due to ice-albedo feedback.
- ERA5/Copernicus: authoritative global temperature reanalysis dataset produced by ECMWF.