2024 is declared hottest year on record, how scientists take earths temperature
The year 2024 was the world’s warmest on record globally, and the first calendar year in which global temperatures exceeded 1.5°C above its pre-industrial levels.
The official declaration was made on Friday by the Copernicus Climate Change Service, the European Union’s Earth observation program. It comes as wildfires continue to tear through Los Angeles, California – a disaster scientists say was made worse by climate change.
This record-breaking global heat is primarily driven by humanity’s ongoing greenhouse gas emissions, caused by the burning of fossil fuels. The warming won’t stop until we reach net-zero emissions.
Clearly, the need for humanity to rapidly reduce its greenhouse gas emissions has never been more urgent.
An exceptional year
The Copernicus findings are consistent with other leading global temperature datasets indicating 2024 was the hottest year since records began in 1850.
The global average temperature in 2024 was about 1.6°C above the average temperatures in the late-19th century (which is used to represent pre-industrial levels).
On July 22 last year, the daily global average temperature reached 17.16°C. This was a new record high.
Copernicus also found that each year in the last decade was one of the ten warmest on record. According to Copernicus director Carlo Buontempo:
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We are now teetering on the edge of passing the 1.5ºC level defined in the Paris Agreement and the average of the last two years is already above this level.
These high global temperatures, coupled with record global atmospheric water vapour levels in 2024, meant unprecedented heatwaves and heavy rainfall events, causing misery for millions of people.
How scientists take Earth’s temperature
Estimating the global average surface temperature is no mean feat. The methods vary between organisations, but the overall picture is the same: 2024 was the world’s hottest year on record.
The high global average temperature of 2024 wouldn’t have been possible without humanity’s greenhouse gas emissions. The El Niño climate driver also played a role in the first part of the year. It warmed Earth’s surface – particularly over a large swathe of the central and eastern Pacific – and increased global average surface temperature by up to 0.2°C.
Does this mean the Paris Agreement has failed?
The global Paris Agreement aims to limit global warming to 1.5°C above pre-industrial levels. So, if 2024 was about 1.6°C above pre-industrial levels, you might think the world has failed to meet this goal. But it hasn’t, yet.
The success of the Paris Agreement will be measured against longer periods than temperatures over a year. That eliminates natural climate variability and factors such as El Niño and La Niña, to build a clearer picture of climate change.
However, the statistics for 2024 are certainly a bad sign. It shows humanity has its work cut out to keep global warming well below 2°C, let alone 1.5°C.
More heat guaranteed
There’s one very important thing to understand about climate change: the amount of greenhouse gases that humans emit over time is roughly proportional to the increase in global temperatures over that same period.
This near-linear relationship means every tonne of greenhouse gas emissions from human activity causes about the same amount of global warming. So, the faster we decarbonise the global economy, the sooner we can halt global warming and reduce its harms.
This year is unlikely to be quite as hot as 2024 because the El Niño has passed. But unfortunately, Earth will continue to experience record hot global temperatures for at least the next few decades.
This is all the more reason for humanity to move faster in decarbonising our society and economy. It’s not too late to shift the long-term trajectory of Earth’s climate.
