Washington: A 13-month streak of record-breaking global warmth has ended.
From June 2023 until June 2024, air and ocean surface water temperatures averaged a quarter of a degree Celsius higher than records set only a few years previously. Air temperatures in July 2024 were slightly cooler than the previous July (0.04°C, the narrowest of margins) according to the EU’s Copernicus Climate Change Service.
July 2023 was in turn 0.28°C warmer than the previous record-hot July in 2019, so the remarkable jump in temperature during the past year has yet to ease off completely. The warmest global air temperature recorded was in December 2023, at 1.78°C above the pre-industrial average temperature for December – and 0.31°C warmer than the previous record.
Global warming has consistently toppled records for warm global average temperatures in recent decades, but breaking them by as much as a quarter of a degree for several months is not common. The end of this streak does not diminish the mounting threat of climate change.
So what caused these record temperatures? Several factors came together, but the biggest and most important is climate change, largely caused by burning fossil fuels.
What caused the heat streak
Temperatures typical of Earth 150 years ago are used for comparison to measure modern global warming.
The reference period, 1850–1900, was before most greenhouse gases associated with global industrialisation – which increase the heat present in Earth’s ocean and atmosphere – had been emitted.
July 2024 was 1.48°C warmer than a typical pre-industrial July, of which about 1.3°C is attributable to the general trend of global warming over the intervening decades.
This trend will continue to raise temperatures until humanity stabilises the climate by keeping fossil fuels in the ground where they belong.
But global warming doesn’t happen in a smooth progression.
Like UK house prices, the general trend is up, but there are ups and downs along the way.
Behind much of the ups and downs is the El Niño phenomenon. An El Niño event is a reorganisation of the water across the vast reaches of the Pacific Ocean.