A single hot month proves nothing. A single hot month sitting on top of a ranked series, with a known mechanism still building underneath it, is evidence. Learn to tell the difference and you have most of what Core 2 asks for.
What the instruments actually recorded
The Copernicus Climate Change Service published its August bulletin on 10 September 2026. The headline number is a global average surface air temperature of 16.96°C, which ties August 2026 with July 2023 as the warmest month in the record. NOAA, NASA and the WMO reached the same conclusion from their own datasets, and the US National Centers for Environmental Information called it the warmest August since records begin in 1850.
Notice how the same month gets three different numbers depending on what it is measured against. This is not spin. It is the reason every figure you take from here needs its baseline written next to it.
| Measure | August 2026 | Why it matters |
|---|---|---|
| Global average surface air temperature | 16.96°C | Joint warmest month ever recorded, tied with July 2023. |
| Anomaly against 1991–2020 | +0.85°C | The recent baseline. Makes the change look modest. |
| Anomaly against 1850–1900 | +1.65°C | The pre industrial baseline. Back above the 1.5°C line that the Paris Agreement is written around. |
| Sea surface temperature, 60°S to 60°N | 21.07°C | Tied with March 2024 for the highest of any month. The ocean holds the heat. |
| Arctic sea ice | 12th lowest August | Below average. |
| Antarctic sea ice | 4th lowest August | Below average at both poles in the same month. |
| Western Europe, June to August | Warmest summer on record | Beat the 2003 summer that killed tens of thousands. |
One more line from the ranking, because it does more work than the record itself: all ten of the warmest Augusts ever measured have happened since 2016.
The engine, and why it is not finished
El Niño is measured in the Niño 3.4 region of the equatorial Pacific, between 170°W and 120°W. Warm water piles up in the central and eastern Pacific, the trade winds slacken, and the atmosphere redistributes rainfall across half the planet. The escalation this year has been fast.
Celeste Saulo, the WMO Secretary General, described the trajectory as potentially off the charts we have used for the past four decades
. Note the hedge in her sentence. It is a conditional forecast, not a measurement, and you should treat the two differently when you cite them.
Where the redistribution lands
El Niño does not warm everywhere evenly. It moves rainfall. The September to November outlook carries an increased likelihood of above normal temperatures across almost all land areas, with drought risk concentrated in the Amazon, Indonesia and Australia, and a disrupted monsoon over India. Those four are not random: they sit where the Walker circulation is displaced when the Pacific warms.
The compounding matters more than any single forecast. The WMO’s State of the Climate in the South-West Pacific 2025, published on 7 July 2026, found that marine heatwaves covered almost the entire ocean area of that region in 2025 — the most extensive coverage ever recorded in a year without an El Niño. Regional sea level there has risen at 3.7 ± 0.03 mm a year since 1999. A very strong El Niño is now arriving on top of that.
For scale on the coastal side: global mean sea level rose at 4.7 mm a year across 2014 to 2023, then jumped to 5.9 mm in 2024. Around 770 million people live less than five metres above the high tide line, and small Pacific states are seeing rates more than twice the global average. Tuvalu and the Maldives, both of which have record pages on this site, sit inside that number.
Where it connects in this course
Causes and consequences in one month of data, with a named mechanism you can explain rather than assert.
770 million people below five metres. Displacement is a demographic process before it is a humanitarian one.
A strong El Niño hits food, water and energy in the same season. The nexus, demonstrated.
An index measured in one ocean box at 145°W changes harvests in Indonesia and river levels in Brazil.
Both poles below average sea ice in the same month, which is not the normal seasonal pattern.
Anomalies against baselines, ranked series, conditional forecasts. Exactly the reading Paper 2 resources demand.
For Monday
- The same month is +0.85°C against one baseline and +1.65°C against another. Both are correct. Explain how a writer could choose a baseline to argue either urgency or calm, and what that means for how you read a resource booklet.
- One record month proves very little. All ten warmest Augusts falling since 2016 proves rather more. What exactly does the second statement add?
- In 2025 marine heatwaves covered almost the whole South-West Pacific in a year with no El Niño. What does that imply about what a very strong El Niño will do there now, and what would you need to check before saying so in an exam answer?
- Sea level around small Pacific states is rising at more than twice the global rate. Explain why the global figure is the wrong number to plan Tuvalu’s future with, using scale as a concept rather than a word.
- Choose one of the Amazon, Indonesia, Australia or India. Explain the mechanism that links a warm Niño 3.4 to drier conditions there, then say what makes that place vulnerable for reasons that have nothing to do with rainfall.
- Saulo’s “off the charts” line is a forecast, not a measurement. How should that change the way you cite it, and how would you cite it fairly?
- Compare this with the Colorado River story. One is a hazard forecast, the other a governance decision. Both are about water. Where do they meet?
Sources
- Copernicus Climate Change ServiceAugust was the world’s joint hottest month on record — The primary bulletin, 10 September 2026. Go here for the numbers rather than to anybody’s summary of them.
- UN NewsThe world just had the hottest August ever — 11 September 2026. Useful because it shows four independent agencies reaching the same result, which is the point about reliability.
- WMOEl Niño set to become very strong — 3 September 2026. The Niño 3.4 values and the probabilities. Read the hedging language carefully; it is doing work.
- WMOState of the Climate in the South-West Pacific 2025 — 7 July 2026. Regional sea level and marine heatwave figures, published before this El Niño strengthened.
- UN NewsRising seas, rising stakes — 29 August 2026. Sea level rates and the population exposure figures.
- Al JazeeraUN warns El Niño could be off the charts — 3 September 2026. News reporting of the same WMO update. Compare its framing with the WMO’s own wording and note what changes.
Current as of 15 September 2026. The WMO issues El Niño updates roughly monthly and Copernicus publishes a bulletin in the first half of every month, so check both before citing any figure here after October.