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Wullie Davidson: Record Global Temperature in 2023

2023 Was A Year For The Record Books

It smashed the record high annual global temperature anomaly of 1.01 C above the 1951-80 average, first set in the record El Nino year of 2016, and equalled in 2020, by an astounding 0.17 C. Record temperatures, well above previous marks, first began to be seen in March in oceanic sea surface temperatures (SSTs). Then, global land temperatures followed suit in June, and have remained at record high levels ever since. The most extreme global combined land/sea monthly temperature anomaly occurred in September (+1.48 C), which beat the previous September record by an incredible 0.50 C, prompting one scientist to declare “In my professional opinion, September was absolutely gobsmackingly bananas”.

Scientists are at a loss to explain the surge, but the fact that it began in the ocean may be significant. It has been suggested that recent legislation to prevent ships using high sulfur bunker oil as fuel, may have played a part. When high sulfur fossil fuels are burned, the sulfur is converted to sulfur dioxide (SO2), which both reflects back incoming sunlight, and acts as a highly efficient condensation nucleus for water molecules, enhancing cloud formation. Both mechanisms act to cool the surface, but I’m not convinced that it’s a major factor. The current strong El Nino will have played a part, but the warming surge began before its onset, and previous very strong El Ninos were associated with much smaller temperature increases, compared to what we’re seeing now. So, something else must be going on, but no one quite knows what.

US Billion Dollar Weather Disasters

Floods Fort Lauderdale 2023 https://commons.wikimedia.org/wiki/File:2023_florida_floods.jpg

The US suffered 28 weather related disasters in 2023, costing at least $1 billion (inflation adjusted). The previous record was 22, set in 2020. According to a new report issued by the giant reinsurance group, Munch Re, thunderstorms in North America and Europe in 2023, were “more destructive than ever before”, with overall losses of $76 billion, and insured losses of $58 billion. Severe thunderstorms are associated with destructive ‘straight line’ winds, tornadoes, flash flooding and large hail damage. Large hail up to the size of baseballs usually accounts for most of the damage, damaging crops, and severely impacting cars, outhouses, roofs etc. As it gets warmer, the hail will get larger and more frequent.

Tropical Cyclones

Tropical Cyclone Summary Map 2023 https://upload.wikimedia.org/wikipedia/commons/8/88/2023_tropical_cyclone_summary_map.png

There were a total of 78 named tropical cyclones throughout the globe in 2023. This is slightly fewer than the average, and more evidence to support the observation that numbers are not increasing as was expected, in response to warming oceans, although numbers in the North Atlantic appear to be on the increase. 2023 was the fourth busiest year for tropical storms and hurricanes in the Atlantic, despite the ongoing EL Nino, which usually suppresses activity, by increasing wind shear. However, few of them made landfall, mostly going northwards into the open ocean to dissipate in colder waters.

Although there is, as yet, scant evidence for an increasing number of tropical storms worldwide, the number of major (category 3, 4 and 5) cyclones/hurricanes does seem to be increasing, particularly category 5s. There are seven ‘basins’ in the ocean, where tropical cyclones develop. 2023 was the first year in which at least one category 5 storm formed in all seven basins.

Cyclone Gabrielle became the costliest southern hemisphere cyclone on record in February, after causing (US) $8.1 billion in damage in New Zealand’s North Island. This was mainly from rainfall flooding, the 19 inches of rain it brought falling on saturated ground, after one of the wettest summers in New Zealand’s history.

Cyclone Freddy began life in the Timor Sea in February, between Australia and New Zealand, and became the longest lived cyclone on record (37 days). It crossed the whole of the southern Indian Ocean, attaining category 5 strength, before making landfall in Madagascar as a category 3. It eventually became the first cyclone on record to visit landlocked Malawi, where it stalled and unleashed a huge amount of flooding rains. Freddy caused 1,436 known fatalities, 1,216 of them in Malawi.

Hurricane Otis Acapulco Brightness Temperature (Band 31; Night) MODIS Imagery (Desaturated) from NASA’s Terra Satellite, https://upload.wikimedia.org/wikipedia/commons/3/33/Otis_2023-10-25_0431Z.png

In October, hurricane Otis became the most powerful storm ever known to make landfall on the western coast of the Americas, coming ashore near Acapulco, Mexico, as a 165 mph category 5 hurricane. Most of the destructive hurricanes that impact Mexico do so on its eastern coast, in the Gulf of Mexico, or Caribbean, so Otis was quite unusual. Most storms that form off Mexico’s western coast head out into the Pacific. Otis did an estimated $16 billion of damage, making it the costliest hurricane in Mexico’s history.

In September, storm Daniel became the deadliest Mediterranean tropical-like cyclone in recorded history, and the costliest outside of the North Atlantic. It affected Greece, Bulgaria and Turkey with widespread flooding. Torrential rain in Libya caused two dams to fail, and the final death toll there may never be known. 4,361 fatalities were confirmed, with some estimates in excess of 20,000. Damages were estimated at $21 billion.

Droughts and Wildfires

Wildfires Quebec 2023. Contains modified Copernicus Sentinel data 2023, CC BY 2.0 https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons

Canadian Wildfires

The Canada wildfire season usually begins in May, but dry conditions saw an unusually early start in March. About 5% of Canada’s forested area burned and, given the size of Canada, that’s a very large area, about six times the annual average, and more than 2.5 times the previous record. Roughly half of North American wildfires are believed to be caused by lightning, and global warming is expected to double the amount of lightning by the end of the century, although this is based on warming projections that are considered by many to be too conservative. As a result of the smoke from these distant wildfires, New York City briefly became the most polluted city on the planet.

Hawaiian Wildfire

In Hawaii, the typical area burned by wildfires has almost quadrupled in recent years. Experts have blamed the increase on the spread of non native vegetation, such as guinea grass, and hotter, drier weather, due to climate change. In August, the deadliest wildfire to afflict the US in more than 100 years devastated Maui, Hawaii’s largest island. The fire is believed to have caused more than 100 deaths, destroyed 2,207 buildings, and cost $5.5 billion.

Drought La Sequia, Uquguay Enxuta, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons

South American Drought

In South America, a severe multiyear drought culminated in record weather related damages for Argentina and Uruguay. In 2023, the drought damage for Argentina was $9.2 billion, and $1.3 billion for Uruguay, both record totals. Neighbouring Chile had its deadliest ever wildfire season on record, with 26 fatalities.

Wullie Davidson, January 2024

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