The researchers also found the thermal expansion of sea water caused by this global warming contributed to around 40 per cent of the total sea level rise seen in tide gauges from 1873 to 1955. The remaining 60 per cent was likely to have come from the melting of ice sheets and glaciers.
"Our research revealed warming of the planet can be clearly detected since 1873 and that our oceans continue to absorb the great majority of this heat," said lead author Dr Will Hobbs, a researcher at the University of Tasmania’s Institute for Marine and Antarctic Studies and the Australian Research Council’s Centre of Excellence for Climate System Science.
"Currently scientists estimate the oceans absorb more than 90 per cent of the heat trapped by greenhouse gases, and we attribute the global warming to anthropogenic causes."
The Challenger expedition, from 1872-1876, was the world’s first global scientific survey of life beneath the ocean surface. Along the way scientists measured ocean temperatures, lowering thermometers hundreds of metres deep on ropes made from Italian hemp during its voyage.
Researchers combined these data with modern observations and used both in state-of-the-art climate models to get a picture of how the world’s oceans have changed since the Challenger’s voyage.
"The key to this research was to determine the range of uncertainty for the measurements taken by the crew of the Challenger," said study co-author Josh Willis, a climate scientist at NASA’s Jet Propulsion Laboratory.