A recent, rapid heating of the world's oceans has alarmed scientists concerned that it will add to global warming.

This month, the global sea surface hit a new record high temperature. It has never warmed this much, this quickly.

Scientists don't fully understand why this has happened.

But they worry that, combined with other weather events, the world's temperature could reach a concerning new level by the end of next year.

Experts believe that a strong El Niño weather event - a weather system that heats the ocean - will also set in over the next months.