Contributors to the record heat of 2023

NASA has released a nice breakdown of the likely contributors to the record-setting heat that the world experienced last year.

Clearly, the main contributor to this warmth was the steadily increasing concentration of atmospheric greenhouse gases, such as carbon dioxide and methane, which act as a blanket, allowing less heat to escape back into space. The global concentration of atmospheric carbon dioxide (CO2) now stands at 424 parts per million, which is the highest it has been in the last 800,000 years, according to NASA.

El Niño came on strong in 2023. El Niño is the abnormal warming of the surface waters along the equatorial Pacific due to a shift in prevailing winds. El Niño has often coincided with some of the warmest years on record and likely played a much smaller role in the record-setting heat.

Once again, the highest average temperatures relative to normal were found in the far northern latitudes. See NASA image below.

Long-term ocean warming has been occurring over the last century, and the result has been another year of combined, record-setting ocean temperatures. Ocean heat waves are also becoming increasingly common.

Aerosols, which can have a cooling influence on global temperature by reflecting more of the sun's light back into space, have been decreasing in recent decades. This is mainly due to more government regulations to reduce air pollution.