A record 15 national heat records have been broken since the start of this year, an influential climate historian has told the Guardian, as weather extremes grow more frequent and climate breakdown intensifies. An additional 130 monthly national temperature records have also been broken, along with tens of thousands of local highs registered at monitoring stations from the Arctic to the South Pacific, according to Maximiliano Herrera, who keeps an archive of extreme events. He said the unprecedented number of records in the first six months was astonishing. “This amount of extreme heat events is beyond anything ever seen or even thought possible before,” he said. “The months from February 2024 to July 2024 have been the most record-breaking for every statistic.” This is alarming because last year’s extreme heat could be largely attributed to a combination of man-made global heating – caused by burning gas, oil, coal and trees – and a natural El Niño phenomenon, a warming of the tropical Pacific Ocean surface that is associated with higher temperatures in many parts of the world. The El Niño has been fading since February of this year, but this has brought little relief. “Far from dwindling with the end of El Niño, records are falling at even much faster pace now compared to late 2023,” said Herrera. New ground is broken every day at a local level. On some days, thousands of monitoring stations set new records of monthly maximums or minimums. The latter is particularly punishing as high night-time temperatures mean people and ecosystems have no time to recover from the relentless heat. In late July, for example, China’s Yueyang region sweltered though an unprecedentedly elevated low of 32C during its dark hours, with dangerously high humidity. The geographic range of all-time national records is staggering. Mexico tied its peak of 52C at Tepache on 20 June. On the other side of the world, the Australian territory of Cocos Islands tied its all-time high with 32.8C on 7 April for the third time this year. But the fiercest heat has concentrated on the tropics. On 7 June, Egypt registered a national high of 50.9C at Aswan. Two days before that Chad tied its national record of 48C at Faya. On 1 May, Ghana hit a new peak of 44.6C at Navrong, while Laos entered new heat territory with 43.7C at Tha Ngon. Herrera said the tropics had set records every day for 15 months in a row. Herrera, a Costa Rican who has been monitoring climate records for 35 years, fills an important gap in global temperature monitoring. Since 2007, international records are archived by the World Meteorological Organization (WMO), which organises expert panels to scrutinise each one in a time-consuming process. Meanwhile, national and subnational records are updated hourly or daily by a plethora of different organisations. Herrera brings the latter together rapidly, double-checks with local sources, and maintains updates on his Extreme Temperatures Around the World X account. His findings are in line with, and often ahead of, big institutions, all of which are warning of a rapidly heating world. “Sirens are blaring across all major indicators … Some records aren’t just chart-topping – they’re chart-busting. And changes are speeding up,” the UN secretary general, António Guterres, said of last year’s intense global heat. The European Union’s leading monitoring agency, the Copernicus Climate Change Service, recently reported that June was the 13th month in a row to set a monthly temperature record, with temperatures 1.5C above the preindustrial average, bringing more intense heatwaves, extreme rainfall events and droughts; reductions in ice sheets, sea ice, and glaciers, as well as accelerated sea-level rise and ocean heating. The WMO has also reported that at least 10 countries have recorded temperatures above 50C so far this year. There is no end in sight for unwelcome records, according to Carlo Buontempo, the director of Copernicus: “Even if this specific streak of extremes ends at some point, we are bound to see new records being broken as the climate continues to warm. This is inevitable unless we stop adding greenhouse gases into the atmosphere and the oceans.” Hopes of a cooling have so far proved elusive. The preliminary data from the Copernicus ERA5 satellite suggests that 22 July was the hottest day in the Earth’s recorded history, with an average global surface air temperature of 17.15C. Herrera said he hoped extreme weather alerts could prepare the world for what was coming and reduce threats to lives, infrastructure and economies. “It’s during extreme weather that we humans and other species are under stress or at risk, so it’s when we are more potentially vulnerable,” he said. National and territorial weather records broken or tied this year 28 February Cocos Islands tied its all-time highest temperature with 32.8C. It tied it again on 29 February and 7 April. 6 March Costa Rica broke its national record with 41C at Cerro Huacalito. The record was beaten again with 41.5C on 23 March at the same location. 12 March Comoros broke its national record with 36.2C at Hahaya airport. 13 March Congo broke its national record with 39.6C at Impfondo. 24 March Maldives broke its national record with 35.1C at Hanimadhoo. It tied it again on 11 April. 31 March Togo broke its national record with 44C at Mango. 3 April Mali broke its national record with 48.5C at Kayes.. 10 April Belize broke its national record with 42.3C at Barton Creek. This temperature was later tied on 17 May at Chaa Creek. 24 April Chad tied its national record with 48C at Faya. This was tied again on 5 June. 27 April Cambodia broke its national record with 42.8C at Preah Viehar and Svay Leu. 1 May Ghana broke its national record with 44.6C at Navrongo. 1 May Laos broke its national record with 43.7C at Tha Ngon. 29 May Palau tied its national record with 35C at Babelthuap international airport. On 2 June it beat it with 35.6C. 7 June Egypt beat its national record with 50.9C at Aswan. 20 June Mexico tied its national record with 52C at Tepache.