But global warming doesn’t happen smoothly. Like real estate prices, the general trend is upward, but there are ups and downs along the way.
Behind most of the ups and downs is the El Niño phenomenon. The El Niño phenomenon is a reorganization of water over huge areas of the Pacific Ocean. El Niño is so critical to the functioning of the world’s weather because it raises the average air temperature over the entire surface of the Earth, not just over the Pacific. Between El Niño events, conditions can be neutral or in the opposite state called La Niña, which tends to lower global temperatures. The oscillations between these extremes are irregular, and El Niño conditions tend to recur after three to seven years.
The toasty El Niño phase of this cycle began a year ago, peaked in tardy 2023 and is now trending neutral, which explains why the record-breaking streak has come to an end.
The 2023-2024 El Niño was forceful, but not superstrong. That doesn’t fully explain the extraordinary degree to which last year broke temperature records. The exact contribution of other factors has yet to be fully disentangled.
We know that a diminutive positive contribution is made by the Sun, which is in the phase of its 11-year sunspot cycle during which it emits a little more energy towards Earth.
Methane (also a byproduct of the fossil fuel industry, along with cattle and wetlands) is another critical greenhouse gas, and its concentration in the air has increased faster in the last decade than in the previous one.
Scientists are also assessing how much air-cleaning efforts might contribute to warming, because some air pollution particles can reflect sunlight and affect cloud formation.
Temperature rattle
On the other side of the ocean, 2023 was a devastating summer for coral reefs and the ecosystems that surround them. Caribbean and beyond. Then there was the severe bleaching of the Great Barrier Reef off Australia during the Southern Hemisphere summer. While mass mortality events on coral reefs around the world tend to occur during El Niño years, the underlying trend of climate change poses a long-term threat as corals struggle to adapt to increasing temperature extremes.