Scientists say this is the most comprehensive study to date on global ocean warming.
The research has been published in the journal Nature Climate Change.
The team looked at rising ocean temperatures over the past 50 years, and a dozen models projecting climate change patterns.
Australian based co-author, Dr John Church from Australia's island state of Tasmania says there's no way all of the world's oceans could've warmed by one tenth of a degree Celsius without human impact.
He says nature only accounts for 10 per cent of the increase.
Dr Church says researchers from America, Australia, Japan and India examined a dozen different models used to project climate change, past studies have only looked at a couple at a time.
"And this has allowed the group to rule out that the changes are related to natural variability in the climate system," he said.
Leading climate change and oceanography expert, Professor Nathan Bindoff says scientists are now certain man-made greenhouse gases are the primary cause.
"The evidence is unequivocal for global warming," he said.
He says the new research balances the man-made impacts of warming greenhouse gases and cooling pollution in the troposphere, against natural changes in the ocean's temperature and volcanic eruptions.
"This paper is important because for the first time we can actually say that we're virtually certain that the oceans have warmed, and that warming is caused not by natural processes but by rising greenhouse gases primarily," he said.
The research team says the ground-breaking study will help guide further climate change research and international policy development.