The largest ever recorded leap in the amount of carbon dioxide laden in the world’s atmosphere has just occurred, according to researchers who monitor the relentless accumulation of the primary gas that is heating the planet.

The global average concentration of carbon dioxide in March this year was 4.7 parts per million (or ppm) higher than it it was in March last year, which is a record-breaking increase in CO₂ levels over a 12-month period.

The increase has been spurred, scientists say, by the periodic El Niño climate event, which has now waned, as well as the ongoing and increasing amounts of greenhouse gases expelled into the atmosphere due to the burning of fossil fuels and deforestation.

In June, the National Oceanic and Atmospheric Administration announced that global concentration of CO₂ had hit 421ppm, a 50% increase on pre-industrial times and the highest in millions of years. The latest reading from Mauna Loa shows the world at around 426ppm of CO₂.