"The global warming signal is a lot easier to detect if it is changing in the oceans than on the surface". That in turn is forcing fish to flee to cooler waters. "There is no doubt, none!" the authors wrote in a statement.
Five years ago, a United Nations panel estimated how quickly the world's oceans would continue to heat up as the planet warms due to climate change.
The newly available data show stronger ocean warming since 1960 than earlier reported by the IPCC's Fifth Assessment Report in 2013.
"Ocean heating is a very important indicator of climate change, and we have robust evidence that it is warming more rapidly than we thought", said co-author Zeke Hausfather, a graduate student in the Energy and Resources Group at the University of California, Berkeley.
The latest analysis published in Science shows trends add to a growing body of evidence that ocean warming is accelerating.
The four studies, published between 2014 and 2017, provide better estimates of past trends in ocean heat content by correcting for discrepancies between different types of ocean temperature measurements and by better accounting for gaps in measurements over time or location.
Assuming a "business-as-usual" scenario in which no effort has been made to reduce greenhouse gas emissions, the Coupled Model Intercomparison Project 5 (CMIP5) models predict that the temperature of the top 2,000 meters of the world's oceans will rise 0.78 degrees Celsius by the end of the century. The Science study sums up some of the catastrophic impacts of warming oceans in one alarming list, which includes "rainfall intensity, rising sea levels, the destruction of coral reefs, declining ocean oxygen levels, and declines in ice sheets; glaciers; and ice caps in the polar regions".
"While 2018 will be the fourth warmest year on record on the surface, it will most certainly be the warmest year on record in the oceans, as was 2017 and 2016 before that", Hausfather said. Dubbed Argo, the AI fleet has provided consistent ocean warming data since the mid-2000s, and enabled the team to correct previous ocean warming observations. According to the study, sea levels could rise by 30cm by the year 2100. And, unlike surface temperatures, ocean temperatures are not affected by year-to-year variations caused by climate events like El Nino or volcanic eruptions.
For every 1 degree Celsius (1.8 degree Fahrenheit) increase in temperature, there is 7% more moisture in the air.
That is driving sea level rise, as oceans warm and expand, and helping fuel more intense hurricanes and other extreme weather, scientists warn.
The world's oceans are warming at an accelerated rate and are much warmer than scientists thought - and things could get a lot worse if nothing is done to stop climate change, according to anew study.