A new research study published in science journal Nature has suggested that ocean warming is at “the high end” of previous estimates, with serious implications as to whether the world can keep global temperature rise below 1.5 degrees during this century.

According to the researchers, the data suggests that over the last 25 years heat uptake by the oceans has been 60% more than previous studies indicated. The study says that the previous estimates “all use the same imperfect ocean dataset and share additional uncertainties resulting from sparse coverage, especially before 2007.”

Oceans absorbs vast quantities of heat as a result of increased concentrations of greenhouse gases in the atmosphere, mainly from fossil fuel consumption.

The new study is an independent estimate which uses measurements of atmospheric oxygen (O2) and carbon dioxide (CO2)—levels of which increase as the ocean warms and releases gases—as a “whole-ocean thermometer.”

The recent special report published by the Intergovernmental Panel on Climate Change (IPPC) in October says that global warming must be kept to below 1.5°C in order to mitigate the disastrous impacts of runaway climate change.

However, the IPCC has warned that the current nationally stated mitigation ambitions until 2030 could result in a global warming of about 3°C by 2100.

According to the IPCC, over 90% of the world’s excess heat from greenhouse gases has been absorbed by the oceans.

The results of the new study suggest that it will potentially be even more difficult to keep warming below 1.5°C or even 2°C and that carbon emissions from human activities must be reduced by 25% more than previously estimated.

Click here to access the report Quantification of ocean heat uptake from changes in atmospheric O2 and CO2 composition in Nature