The world’s oceans rose to the highest temperatures ever recorded by far in 2017, scientists have warned. Research by a team of Chinese experts found the upper 2,000m of ocean water were far warmer in 2017 than the previous hottest year in 2015. The findings, published in the journal Advances in Atmospheric Sciences, show the annual electricity generation in China is 699 times smaller than the heat increase in the oceans last year. “The long-term warming trend driven by human activities continued unabated,” wrote research authors Lijing Cheng and Jian Zhu, Writing in The Guardian, John Abraham, a professor of thermal sciences at the University of St Thomas in Minnesota, said last year’s dramatic increase in temperatures made 2017 by far the hottest year on record for the world’s oceans. The findings also come after previous research showed greenhouse gas levels in the atmosphere have risen to record high in 2017. Last year was also one of the hottest ever recorded. Scientists have reported that 2017 was the second or third warmest year – depending on the set of data analysed – and the hottest year ever without El Niño, a natural phase of the climate system that results in warmer temperatures in the Pacific Ocean. Mr Cheng and Mr Zhu said more than 90 per cent of the Earth’s residual heat related to global warming is absorbed by the oceans and the heat record “robustly represents the signature of global warming”. The authors looked at the history of ocean warming over the last 60 years in order to compare the data. They added that measurements of ocean heating are a more reliable indicator than atmospheric measurements for tracking “vital signs of the health of the planet”. According to the Institute of Atmospheric Physics’ ocean analysis, the last five years have been the warmest years in the oceans.