Jan 02 2024

2023 Hottest Year on Record

What everyone knew was coming is now official – 2023 was the warmest year on record. This means we can also say that the last 10 years are the hottest decade on record. 2023 dethrones 2016 as the previous warmest year and bumps 2010 out of the top 10. Further, in the last half of the year, many of the months were the hottest months on record, and by a large margin. September’s average temperature was 1.44 C above pre-industrial levels, beating the previous record set in 2020 of 0.98 C. The average for 2023 is 1.4 C, beating the previous record in 2016 of 1.2 C. This also makes 2023 probably the warmest year in the last 125,000 years.

There is no mystery as to why this is happening, and it’s exactly what scientists predicted would happen. Remember the global warming “pause” that was allegedly happening between 1998 and 2012? This was the pause that never was, a short term fluctuation in the long term trend and a bit of statistical voodoo. Global warming deniers were declaring that global warming was over, it was never real, it was just a statistical fluke and the world was regressing back to the mean. Meanwhile, scientists said the long term trend had not altered and predicted the next decade would be even warmer. In retrospect, it turns out that during the alleged “pause” more heat was going into the oceans and was not fully reflected in surface temperatures.

The best test of a scientific hypothesis is its ability to make predictions about future data. The deniers were predicting that the Earth would simply return to baseline temperatures, while the scientific community were united in predicting that the next decade (now the past decade) would see continued warming.

There are a couple of reasons why 2023 broke all records – anomalous warming due to greenhouse gas emissions, and El Nino. Global weather patterns are either in an El Nino state, with higher than average temperatures, La Nina, with lower than average, or normal with average temperatures. We cycle through these conditions every five or six years. The last El Nino was at the end of 2015 and beginning of 2016, which is why 2016 was the warmest year on record – until the current El Nino, which is continuing into 2024. This means that 2024 will likely also break some records and probably be the warmest year on record, and then we will likely see a few years of top 10 but not record-breaking temperatures, and then the cycle will repeat.

If you look past the background noise and short-term cycles and other effects, there is a consistent trend in global average temperatures – the Earth is warming. Climate scientists have systematically eliminated all known natural causes – it’s not solar forcing or the galactic rotation or anything. It is because we are pumping CO2 and methane into the atmosphere, gases which trap heat and alter the homeostatic temperature of the Earth. Carbon emissions hit a record high in 2023, totaling more than 40 billion tons, 37 billion of which was from burning fossil fuels. According to NASA:

“The concentration of carbon dioxide in Earth’s atmosphere is currently at nearly 412 parts per million (ppm) and rising. This represents a 47 percent increase since the beginning of the Industrial Age, when the concentration was near 280 ppm, and an 11 percent increase since 2000, when it was near 370 ppm.”

And yes, almost all of that CO2 is from industrial release. Deniers, apparently not missing any bad argument, have sometimes falsely claimed that volcanoes release more CO2 than industry. In reality, all volcanoes (on land and under the sea) release only between 0.13 gigaton to 0.44 gigaton of CO2 per year. That is a round-off error of industrial release.

The results of this warming are also being felt, perhaps more in 2023 than any previous year. There are many ways to measure the effects of a warming climate, and they are all pointing in the same direction. As the planet is warming, ice is melting. One measure of this effect is the Antarctic winter maximum sea ice. In 2023 we measured the lowest winter maximum on record by a large margin. Arctic sea ice was also far below baseline levels, but not quite record-breaking. Global sea ice continues its long term downward trend. The number of heat waves also increased, with higher temperatures and longer durations. And as a result wildfires were on the increase in 2023.

Scientists estimate that by 2030 global average temperatures will be consistently above 1.5 C above pre-industrial levels. This now seems unavoidable. We (the world) haven’t yet even decreased the amount of CO2 we are releasing each year (apart from the pandemic anomaly, but we are back on track). There are still (amazingly) deniers out there, but it seems that reality is setting in more and more. Despite this, we cannot seem to get collectively serious about tackling this extremely serious situation. We just don’t have the political infrastructure and mechanisms for the kind of coordinated effort that would be necessary. COP28 was yet another attempt at such an effort, but proved (once again) to be little more than theater. Perhaps it’s better than nothing, at least a recognition that we should be doing something. Or perhaps not – I worry it just gives us cover to keep burning fossil fuels.

It seems progress is made or not made mostly at the national level. The big emitting countries need to phase out coal first, then all fossil fuels, by rapidly building out low carbon energy sources and electrifying transportation and other industries. We can all do our little part, but nothing really matters if we keep burning massive amounts of fossil fuel. I will probably be writing some version of this post as my first article for 2025.

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