According to a study conducted by Princeton and the Scripps Institution of Oceanography at the University of California-San Diego, each year during the past quarter century, the world’s oceans have absorbed an amount of heat energy that is 150 times the energy humans produce as electricity annually. Researchers suggest that the strong ocean warning is caused because Earth is more sensitive to fossil-fuel emissions than previously thought.
Namely, the researchers reported in the journal Nature Nov. 1 that the world’s oceans took up more than 13 zettajoules of heat energy each year between 1991 and 2016.
Laure Resplandy, an assistant professor of geosciences and the Princeton Environmental Institute, addressed that the heat the oceans absorb has reached more than 60% per year than the figure in the 2014 Fifth Assessment Report on climate change from the United Nations Intergovernmental Panel on Climate Change (IPCC).
As Resplandy stated
Imagine if the ocean was only 30 feet deep. Our data show that it would have warmed by 6.5 degrees Celsius every decade since 1991. In comparison, the estimate of the last IPCC assessment report would correspond to a warming of only 4 degrees Celsius every decade.
What’s more, scientists are aware that the ocean absorbs approximately more than 90% of all the excess energy produced as the Earth warms. Thus, Ralph Keeling, a Scripps Oceanography geophysicist and Resplandy’s former postdoctoral adviser stated that it is now easy to estimate the surface warming.
The findings from estimating the surface warming, result to scientists being confident on decreasing the climate sensitivity, particularly closing off the possibility of very low climate sensitivity. Specifically, climate sensitivity is used to evaluate allowable emissions for mitigation strategies. Climate sensitivity is used to evaluate allowable emissions for mitigation strategies.
The majority of climate scientists have agreed that whether global average temperatures are to exceed pre-industrial levels by 2℃, society will definitely face the dangerous consequences of climate change.
Scientists support that if people aspire to prevent temperatures from rising above that mark, the human activities, as GHG emissions, should be limited and decreased by 25%.
Although previous scientists attempted to measure ocean temperatures, the results were uncertain because of the gaps in coverage. Yet, today robotic sensors, also known as Argo, make the research fruitful. However, because the data of the sensors goes back to 2007, Argo is able to measure only the upper half of the ocean.
In addition, Resplandy and her co-authors used Scripps’s high-precision measurements of oxygen and carbon dioxide in the air to acknowledge how much heat the oceans have stored during the timeframe they conducted the research.
[smlsubform prepend=”GET THE SAFETY4SEA IN YOUR INBOX!” showname=false emailtxt=”” emailholder=”Enter your email address” showsubmit=true submittxt=”Submit” jsthanks=false thankyou=”Thank you for subscribing to our mailing list”]
They managed to measure ocean heat by looking at the combined amount of O2 and CO2 in air, what they call ‘atmospheric potential oxygen‘ or APO.
Consequently, as the ocean warms, the gases are released into air, which increases APO levels. APO is also affected by burning fossil fuels and by an ocean process involving the uptake of excess fossil-fuel CO2.
The researchers were able to calculate how much APO emanated from the ocean becoming warmer, by comparing the changes in APO they observed with the changes expected due to fossil-fuel use and carbon dioxide uptake.
Finally, the study was funded by the National Oceanic and Atmospheric Administration and the Princeton Environmental Institute and Resplandy and Keeling worked with co-authors Yassir Eddebbar and Mariela Brooks from Scripps, Rong Wang from Fudan University in China, Laurent Bopp from École Normale Supérieure in France, Matthew Long from the National Center for Atmospheric Research, John Dunne from the NOAA Geophysical Fluid Dynamics Laboratory, and Wolfgang Koeve and Andreas Oschlies from the GEOMAR Helmholtz Centre for Ocean Research in Germany.
