Future Timeline

(CNN) Ocean surface heat is at record-breaking levels. Temperatures began climbing in mid-March and skyrocketed over the course of several weeks, leaving scientists scrambling to figure out exactly why.

Temperatures have fallen since their peak in April – as they naturally do in the spring – but they are still higher than they have ever been on record for this time of year.

“It is remarkable,” said Gregory C. Johnson, an oceanographer at the National Oceanic and Atmospheric Administration, which calculates the ocean surface temperature using a network of ships, buoys, satellites and floats.

Although it’s still preliminary data, if it holds up, he said, “this is another milestone.”

The record may not seem huge – it’s nearly two-tenths of a degree higher than the previous record in 2016 – but given how much heat is needed to warm up this huge body of water, “it’s a massive amount of energy,” Matthew England, professor of ocean and climate dynamics at the University of New South Wales, Australia, told CNN. ...............(more)

The catastrophic Australian bushfires in 2019–2020 contributed to ocean cooling thousands of miles away, ultimately nudging the Tropical Pacific into a rare multi-year La Niña event that dissipated only recently.

The research was led by the National Center for Atmospheric Research (NCAR) and is published in Science Advances.

La Niña events tend to impact the winter climate over North America, causing drier and warmer than average conditions in the southwest U.S., wetter weather in the Pacific Northwest, and colder temperatures in Canada and the northern U.S. Because the emergence of La Niña can often be predicted months in advance, it's an important phenomenon for seasonal climate forecasts.

"Many people quickly forgot about the Australian fires, especially as the COVID pandemic exploded, but the Earth system has a long memory, and the impacts of the fires lingered for years," said NCAR scientist John Fasullo, lead author of the study.