The world's oceans were warmer in 2019 than at any point in recorded human history, a study has found.
According to the report - Record-Setting Ocean Warmth Continued in 2019 - the oceans' warmest ten years on record were all measured in the past decade.
Last year's ocean temperature was about 0.075 Celsius above the 1981-2010 average.
Lead author Lijing Cheng said to reach this temperature, the ocean would have taken in 228 sextillion Joules of heat, or 228 followed by 21 zeros.
"The amount of heat we have put in the world's oceans in the past 25 years equals to 3.6 billion Hiroshima atom-bomb explosions," he said.
"This measured ocean warming is irrefutable and is further proof of global warming. There are no reasonable alternatives aside from the human emissions of heat trapping gases to explain this heating."
The research was conducted by a team of climate and ocean scientists from around the world and published in Advances in Atmospheric Sciences.
It found that the heating was distributed throughout the world's oceans, however the Atlantic Ocean and Southern Ocean had absorbed the most heat.
It also found that the rate of warming over the 1987 to 2019 period was four-and-a-half times that recorded between 1955 to 1986, reflecting a major increase in the rate of global climate change.
"It is critical to understand how fast things are changing," co-author John Abraham said.
"The key to answering this question is in the oceans - that's where the vast majority of heat ends up.
"If you want to understand global warming, you have to measure ocean warming."
Warmer ocean temperatures lead to increased evaporation, which in turn contributes to more extreme weather events across the globe, such as flooding, hurricanes and wildfires.
"The global heating has led to an increase in catastrophic fires in the Amazon, California and Australia in 2019, and we're seeing that continue into 2020," Dr Cheng said.
The researchers warn that the ocean warming trend is so severe that it will persist in the immediate future even if the global community meets its Paris Agreement targets.
"However the more we reduce greenhouse gases, the less the ocean will warm," Dr Cheng added.
"Reduce, reuse and recycle and transferring to a clean energy society are still the major way forward."