Fact Check: El Niño, Sea Surface Warming, and Climate Change Claims

The claim posted by Steve Milloy (@JunkScience) asserts that sea surface temperatures are warming strictly for natural reasons and that El Niño alone accounts for temperature spikes without posing a broader threat.

While El Niño is indeed a natural, periodic climate phenomenon originating in the tropical Pacific Ocean, the scientific consensus rejects the claim that overall sea surface temperature warming is solely natural.

Key facts:

1. Human-driven warming is the primary cause of rising ocean temperatures. According to the Intergovernmental Panel on Climate Change (IPCC) and atmospheric organizations like NOAA and NASA, human activities primarily greenhouse gas emissions are the principal driver of global ocean warming. The oceans absorb over 90% of the excess heat trapped in Earth's climate system by greenhouse gases.

2. El Niño occurs on top of human-caused warming. El Niño natural cycles cause short-term temperature fluctuations, but global sea surface temperatures have been steadily rising over decades. The baseline warming means that natural events like El Niño now produce higher temperature peaks than in the past, leading to terms like "supersized" El Niño impacts.

3. Consequences of rising sea surface temperatures are documented. Hotter surface waters contribute to severe marine heatwaves, coral bleaching, altered weather patterns, increased storm intensity, and rising sea levels due to thermal expansion.