The world's oceans have become warmer than at any point in recorded human history, a study has found.
The oceans' warmest 10 years on record were all measured in the past decade, according to the Record-Setting Ocean Warmth Report.
Last year's ocean temperature was around 0.075C (32.1F) above the 1981-2010 average.
Lead author of the study, Lijing Cheng, said the ocean would have taken in 228 sextillion Joules of heat, or 228 followed by 21 zeroes, to reach 2019's temperature.
He said: "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.
"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.
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It found that the heating was distributed throughout the world's oceans, though the Atlantic Ocean and Southern Ocean had absorbed the most heat.
The rate of warming over the 1987 to 2019 period was also discovered to be four-and-a-half times that recorded between 1955 to 1986, reflecting a major increase in the rate of global climate change.
The study's co-author John Abraham said: "If you want to understand global warming, you have to measure ocean warming."
The findings come as climate scientists have warned that bushfires ravaging Australia could become normal conditions unless the world moves rapidly to curb emissions of the greenhouse gases driving climate change.
A review of 57 scientific papers published since 2013 suggested clear links between the role of man-made climate change and the fires, despite Australia's government and parts of its media attempting to downplay it.
"We're not going to reverse climate change on any conceivable timescale. So the conditions that are happening now, they won't go away," said the review's co-author Richard Betts, who is Head of Climate Impacts Research at Britain's Met Office Hadley Centre.
The review found that climate change had led to an increase in the frequency and severity of what scientists have dubbed "fire weather" – which are periods with a high fire risk due to some combination of hotter temperatures, low humidity, low rainfall and strong winds.
It found that the effects had also been observed in the western United States and Canada, as well as southern Europe, Scandinavia, the Amazon and Siberia.
Mr Betts added that Australia was particularly vulnerable to fires since its land area had warmed by more than the rise in average global temperature of around 1C since pre-industrial times.
The World Meteorological Organization said the global temperature increase could reach 3-5C (37.4F-41F) this century – more than three times limits agreed in the 2015 Paris Agreement – if nothing is done to stop rising emissions.