NASA tells US that 2023 was the hottest on record since records began in 1880. Meteorological summer in the Northern Hemisphere is June to August and the period was 0.41 degrees warmer than any previous recorded summer and 1.2 C warmer than the average for the period 1951 to 1980. Exceptional heat swept across much of the world causing extensive wildifires in Canada's boreal forest, heat waves in Europe, South America, Africa and the US, and severe rainfall in Italy, Central Europe and Greece.
The record setting summer continues a long-term warming trend in the data. Both NASA and NOAA have shown that this trend is caused by human greenhouse gas emissions. The natural phenomenon of El Niño also contributed to the record breaking heat. Scientists expect the biggest El Niño effects to occur in February, March and April of this year. A scientist at NASA's Goddard Space Flight Center responsible for compiling the data said that, "it will get worse if we continue to emit carbon dioxide and other greenhouse gases into our atmosphere.”