New hottest day, in a record-breaking 12 months
The new record for hottest day in recent history came on July 21, 2024, when the average global surface air temperature hit 62.76 degrees Fahrenheit (17.09 C).
The post New hottest day, in a record-breaking 12 months first appeared on EarthSky.
Each of the past 12 months was over 1.5C above pre-industrial levels, inching us closer towards breaking the Paris agreement
The blocks in the heat map show the temperature anomaly for each month since 1970
Where they are black, the month breached 1.5C pic.twitter.com/Ci1BHyXALV
— Erwan Rivault (@ErwanRivault) July 8, 2024
Hottest day in recent history
Preliminary data show that a new record for Earth’s hottest day in recent history was set on July 21, 2024. The European Union’s Copernicus Climate Change Service – also known as C3S – has been tracking Earth’s climate patterns since 1940. C3S scientists said on July 23 that July 21, 2024, now holds the new record for hottest day on Earth since at least the early 20th century.
Even more striking is the difference between temperatures in the last 13 months and previous temperature records. Each of the past 12 months exceeded 1.5 C above pre-industrial levels. That number is important politically, because the central aim of the 2015 Paris Agreement is to keep a global temperature rise at 1.5 degrees Celsius. In other words, for the past 12 months, the world has exceeded the temperature limit set by signers of the Paris Agreement.
The Agreement’s ultimate goal is to keep temperature rise in this century well below 2 degrees Celsius above pre-industrial levels. Can we do it in the coming 75 years?
According to C3S Director Carlo Buontempo:
On July 21, C3S recorded a new record for the daily global mean temperature. What is truly staggering is how large the difference is between the temperature of the last 13 months and the previous temperature records. We are now in truly uncharted territory and as the climate keeps warming, we are bound to see new records being broken in future months and years.
The scientists’ announcement said:
While [the hottest day in 2024] is almost indistinguishable from the previous record [in 2023], what really stands out is the difference between the temperatures since July 2023 and all previous years. Since July 3, 2023, there have been 57 days that have exceeded that previous record, distributed between July and August 2023, and during June and July so far in 2024.
From July 2023 to now
C3S reported that – on July 21 – the average global surface air temperature was 62.76 degrees Fahrenheit (17.09 C). That Sunday’s high temperature sets the new record for the hottest day. It breaks the previous daily record, which was set in 2023.
According to these scientists in Europe, in July 2023 Earth set the record for hottest day on Earth four days in a row, finally peaking at 62.74 F (17.08 C). The scientists said:
Before July 2023, the previous daily global average temperature record was 16.8°C (62.24°F), on August 13, 2016.
Why is Earth’s hottest day set at what seems like a relatively cool temperature? It’s just 62.74 F (17.08 C). Bear in mind that, although it’s summer in the Northern Hemisphere now, it’s winter south of Earth’s equator. The average global surface air temperature is an average over the entire globe. That fact notwithstanding, 2024 has brought a brutal summer to some. Heat waves have been pummeling Mexico, the U.S., Europe and Russia.
A pattern of heat
At present, 2023 is the hottest year on record, and 2024 appears poised to break that yearly record. Carlo Buontempo told Reuters we could expect more highs this week, possibly breaking the record again:
When you have these peaks, they tend to cluster together.
Why compare to pre-industrial levels?
Each of the past 12 months exceeded 1.5 C above pre-industrial levels.
And it’s standard to compare temperatures now to pre-industrial levels because this is the level written into the Paris Agreement. In the Paris Agreement, 196 parties agreed to limit temperature increases to well below 2 C above pre-industrial levels and to aim for 1.5 C. So why is 2 C the magic number? As Maria Ivanova at Northeastern University explained:
At two degrees we see dramatic alterations to the ability of the Earth’s system to maintain the conditions that allow for human life and indeed other species’ life.
BREAKING: According to preliminary data from the ERA5 dataset, this past Sunday, July 21, 2024, was the hottest day in Earth's recorded history, with an average global surface air temperature of 17.09°C (62.76°F). pic.twitter.com/xxDMGBh46i
— Nahel Belgherze (@WxNB_) July 23, 2024
Why did we set a new record?
The Copernicus press release said:
The global average temperature tends to reach its annual peak between late June and early August, coinciding with the Northern Hemisphere summer. This is because the seasonal patterns of the Northern Hemisphere drive the overall global temperatures. The large land masses of the Northern Hemisphere warm up faster than the oceans of the Southern Hemisphere can cool down during the northern summer months.
The global average temperature was already at near-record levels in recent days, slightly below the levels of 2023, after being at record levels for the time of year for more than a year.
Adding to the persistently warm temperatures we’ve been having over the globe is the warmth near the South Pole. Much of Antarctica is experiencing above-average temperatures. And Antarctica’s sea ice extent continues to be at near-historic lows.
Bottom line: The new record for hottest day in recent history came on July 21, 2024, when the average global surface air temperature hit 62.76 degrees Fahrenheit (17.09 C).
The post New hottest day, in a record-breaking 12 months first appeared on EarthSky.