The ocean is running a fever
The world's oceans are warmer than ever recorded. The Copernicus Climate Change Service announced that daily global sea surface temperature has reached its highest level since records began. The agency said the ocean is under unprecedented strain, as a strong El Niño adds heat to a planet already warmed by greenhouse gas emissions.
The sea absorbs more than 90 percent of the excess heat trapped by greenhouse gases. That makes ocean temperature one of the clearest signals of climate change. Every record-breaking year on land has been matched by an even larger rise in the ocean.
What warmer seas mean
Warmer oceans fuel stronger storms. Hurricane season has already produced several storms that intensified quickly over hot water. Coral reefs are bleaching across the tropics, and marine heat waves have hit the Atlantic, the Pacific, and the Mediterranean this year.
Warmer water also expands, which pushes sea levels higher. Coastal cities from Miami to Jakarta are feeling the effects during high tides and storms. Fishing communities are seeing fish move toward cooler waters, which disrupts local economies.
A warning for the whole planet
Scientists say the combination of emissions and El Niño is pushing the climate system into new territory. The record comes weeks after several countries reported their hottest months on land. Researchers describe the ocean heat as a warning signal for the entire planet.
There is no quick fix for ocean warming. Cutting emissions remains the only long-term answer, scientists say. In the meantime, governments are investing in early warning systems for marine heat waves and stronger coastal defenses for the storms that warmer seas will bring.