How Much Carbon Dioxide are the Oceans Absorbing?

As the atmosphere warms, the ice melts and the sea rises, many eyes are turning to the mysteries of the ocean to see how they react to climate change. From tide pools to the great depths of the world’s oceans, different species of marine flora and fauna are adjusting to new environments much quicker than expected.

Like a canary in a coal mine, many of the ocean’s unique species serve as front line warning systems for our changing Earth. From seaweed to anemones on up to the vibrant food change from bioplankton to whales, changes to water temperature, salinity, and acidification can not only affect these species, but humanity as well.


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Oceanic Carbon Sink

New research has shown that the world’s oceans, which comprise over 70% of the Earth’s surface, are absorbing more atmospheric carbon dioxide than researchers first estimated. Unfortunately, the climate may be changing faster than even the oceans can keep up. As the ocean heats up, it becomes more acidic, which causes it to lose its ability to hold oxygen. Without adequate oxygen, marine plants and animals must adapt and survive or die.

As the global climate heats up, glaciers and the Arctic ice sheets that cover our most northern climates are melting rapidly. This causes sea levels to rise and make low lying places, like islands and coastlines, incredibly vulnerable to the encroaching tides. As the ocean rises, sea water temperatures are also increasing; although the ocean does absorb extra atmospheric carbon dioxide, which causes the Earth to cool down, it might be too little, too late.

Carbon dioxide continually flows into (blue) and out (red) of the ocean. The oceans store carbon for thousands of years, so most of the carbon dioxide coming out of the ocean within the equatorial pacific was previously in the atmosphere before the time of the industrial revolution. Map: University of Exeter College of Life and Environmental Sciences

Carbon dioxide continually flows into (blue) and out (red) of the ocean. The oceans store carbon for thousands of years, so most of the carbon dioxide coming out of the ocean within the equatorial pacific was previously in the atmosphere before the time of the industrial revolution. Map: University of Exeter College of Life and Environmental Sciences

According to researchers, the world’s oceans have absorbed over 90% of the extra atmospheric heat caused by human-based greenhouse gasses. This number has changed as data from satellites, data banks, and other sources have been compiled. Researchers previously thought that the ocean absorbed about a quarter of the carbon dioxide that is released into the atmosphere by humanity; however, more recent estimates show that this number has increased to about a third of the gasses released by humanity’s industrial activities.

The Future of Ocean Research

Researchers used data gathered from satellites, including the Copernicus Sentinel-3. Additional work has been done on sea surface transfer processes, which helped researchers more accurately model the oceanic carbon sink. Data from the Surface Ocean Carbon Dioxide Atlas was also used in the study. These methods pointed to a carbon sink in the oceans that absorbed about three Gigatonnes of carbon annually.

This information not only updated previous research on atmospheric carbon dioxide and the ocean, but also continues to pave the way for more accurate oceanic models to predict climate change and mitigate its effects on marine and terrestrial life.

Resources

European Space Agency. 8 October 2019. Can Oceans Turn the Tide on the Climate Crisis? Retireved from http://www.esa.int/Applications/Observing_the_Earth/Can_oceans_turn_the_tide_on_the_climate_crisis

Woolf, D. K., Shutler, J. D., Goddijn‐Murphy, L., Watson, A. J., Chapron, B., Nightingale, P. D., … & Holding, T. (2019). Key uncertainties in the recent air‐sea flux of CO2. Global Biogeochemical Cycleshttps://doi.org/10.1029/2018GB006041

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