Record-breaking heat waves, mindboggling melting events, and immense infernos this northern summer were not isolated incidents. Global temperatures have been measured by the National Oceanic and Atmospheric Administration (NOAA) since 1880 – and July 2021 stands as the hottest month recorded.
The landmasses of Asia and North America mean the Northern Hemisphere tends to greater temperature extremes than the south, which is buffered by being mostly ocean. Consequently, July is usually the hottest month of the year worldwide.
In recent years, the rise in global temperatures has meant July has often set records – not just for being the hottest in one specific year, but since widespread recording began.
“In this case, first place is the worst place to be,” NOAA Administrator Dr Rick Spinrad said in a statement. “This new record adds to the disturbing and disruptive path that climate change has set for the globe.”
This announcement comes in the same week the Intergovernmental Panel on Climate Change released its report on the Earth’s dire condition
The record was primarily a result of extraordinary heat in Asia and western North America. Northern Hemisphere land temperatures were 1.54º C (2.77º F) above average, while the hemisphere as a whole was 0.19º C above the previous record. Southern Hemisphere temperatures were warm for this time of year, but below winter records, although countries including Australia and New Zealand had a top-ten warmest July of all time.
Regional conditions can deviate a lot from the global average, particularly over periods of a month or less, so there were still some places that had an unusually cool July – notably southern Africa and the south-eastern United States.
It is the 45th July in succession to exceed the 20th-century average.
The start of 2021, while warm by historical standards, was cool for the 21st century. Consequently, it’s unlikely annual records will be broken on a global scale, even after this baking northern summer.
Nevertheless, the recent European heat record set in Sicily shows 2021 is not done breaking heat records.
The global temperature record only stretches back to the mid-19th century, and even there the first decades are patchy, with large parts of the globe not covered. However, the gap between temperatures then and now is so large that even if the parts of the world without measurements from the era were somewhat hotter than estimated, no month would have approached July 2021. Looking back earlier still, temperature estimates are annual or decadal rather than monthly, based on proxy data such as tree rings and ice cores. However, these proxies produce no sign of a year warm enough to have included a month like July 2021 for tens of thousands of years.