Science & Tech · Science & Environment · 2 hrs ago
Met Office forecasts record CO2 rise in 2027 during strong El Niño
The Met Office forecasts that atmospheric CO2 could rise by a record amount in 2027 as a powerful El Niño develops.
The forecast is based on measurements at the Mauna Loa Observatory in Hawaii.
It predicts a rise of about 3.51 parts per million, which would bring the concentration to 432.2 ppm if accurate.
El Niño is a natural climate pattern that shifts between warmer and cooler phases, and the forecast says the strong event could peak in December and early 2027.
Hot, dry conditions can cause drought and wildfires, making it harder for plants, soils and oceans to absorb CO2; increased air-conditioning use can also add emissions.
Human activity remains the main driver of rising CO2, while El Niño can increase the year-to-year rise.
The forecast highlights that the rate of increase needs to slow substantially to keep warming within the Paris Agreement’s 1.5°C threshold.
The Met Office forecasts that atmospheric CO2 levels could rise by around 3.51 parts per million in 2027.
If accurate, the increase would bring the concentration recorded at Mauna Loa Observatory in Hawaii to 432.2 ppm.
The forecast rise would be the largest year-on-year increase ever forecast by the Met Office.
The Met Office says a strong El Niño can reduce how much CO2 plants, soils and oceans absorb, while human emissions remain the main driver of the long-term increase.
- Who
- The UK Met Office made the forecast. Met Office scientists Emily Wright and Richard Betts explained the factors behind it.
- What
- Atmospheric CO2 could rise by around 3.51 parts per million in 2027, reaching 432.2 ppm at Mauna Loa if the forecast is accurate.
- When
- The forecast was published on November 6, 2026. It concerns the year 2027.
- Where
- The concentration is measured at Mauna Loa Observatory in Hawaii.
- Why
- El Niño can reduce the amount of CO2 absorbed by plants, soils and oceans. Human emissions remain the main driver of the long-term rise.
This story does not have two clearly opposing sides.
The Met Office forecast was reported, predicting a possible record CO2 increase in 2027.
Forecasters expect the El Niño event to reach its peak.
The Met Office forecasts an increase of around 3.51 parts per million in CO2 at Mauna Loa.
- Forecast increase
- Around 3.51 parts per million in 2027
- Projected concentration
- 432.2 ppm at Mauna Loa Observatory, if the forecast is accurate
- Forecast record
- Largest year-on-year increase ever forecast by the Met Office
- Publication date
- November 6, 2026
- Long-term driver
- Human-caused emissions
What people are saying
El Niño events reduce how much they absorb overall, leaving more CO2 in the atmosphere.
Natural climate variability can substantially alter annual rates of CO2 rise, particularly during strong El Niño events.
To follow pathways consistent with limiting warming to 1.5°C, the underlying rate of CO2 increase needs to slow substantially, but this forecast shows that the rate of rise remains too high.