The ocean warmth report published on 9th January 2020, says that there is a “record-setting ocean warming.” The cause is human-emitted greenhouse gases that warm the planet. This finding is consistent with the IPCC September 2019 special report (Cheng, et al., 2020).

This is because the oceans absorb more than 90% of excess heat from the atmosphere and the accumulation of heat causes the oceans to warm. Just last year, 2019, the researchers found that that ocean temperature between 0-2000 meters deep is at a record high (Cheng, et al., 2020).

Data from the Institute of Atmospheric Physics (IAP) and the National Oceanic and Atmospheric Administration/National Center for Environmental Information (NOAA/NCEI) shows the 1981-2010 average water temperature is only 25 Zetta Joules. The 2019 data registered a 228 Zetta Joules (ZJ), showing a significant increase in ocean temperatures (Cheng, et al., 2020).

What does it mean to us

To contextualise what this 228 ZJ of ocean warming means, scientists compare it with the amount of energy released by the explosion of the atomic bomb in Hiroshima Japan in 1945 which is 63,000,000,000,000 Joules amount of energy. Scientists say that in the past 25 years, the warming of the ocean can be compared to 3.6 billion Hiroshima atom-bomb explosions in the oceans or an average of 4 Hiroshima bombs’ worth of energy entering into the ocean every second for the past 25 years (Houser, 2020).

This analogy is mind-boggling. To think that heating of our ocean from the GHG trapped in our atmosphere would have the same amount of energy as the continuous explosions of atomic bombs is sobering.

With this new ocean data, scientists are now able to rank the warmest years since 1950. They have found out that the top 5 warmest years in history have been the last 5 years. Also, the top 10 warmest years, has also been the last 10 years as well. Scientists suggest that this trend of rising ocean temperatures is linked to climate change (Cheng, et al., 2020).

Ocean warming is widely distributed throughout the world’s ocean but it is the Atlantic Ocean and especially the Southern Ocean that showed much higher warming of up to 35 to 43% since 1970. The excess warming in the Southern Ocean is transported northward across the equator and influence recent marine heatwaves in the Tasman Sea (Cheng, et al., 2020).

The evidence of ocean warming is irrefutable according to the study, it also shows an imbalance in the Earth’s energy. What researchers in the study are discovering is that excess GHG trapped in the atmosphere causes global warming, heats up the oceans, and the remaining heat is causing the land to become hotter and drier as well and melts the ice on land and sea. The IPCC Reports are also saying the same thing that human carbon emissions are causing global warming (Cheng, et al., 2020).

The effects of ocean warming

Marine heatwaves caused by ocean warming poses threats to biodiversity, fisheries and economic losses. Researches have discovered that major heatwaves that have happened recently are occurring in the Mediterranean Sea, North Pacific, Equatorial Central Pacific, Tasman Sea, and North Atlantic (Cheng, et al., 2020).

Other consequences of increasing ocean temperatures are rising sea levels because of thermal expansion and added mass from the ice melts. In fact, the last ten years shows the highest in global mean sea level since 1900. Warming ocean waters also reduce dissolved oxygen in the ocean that can destroy sea life, particularly corrals, and other sensitive organisms. Warming also increases evaporation and moisture in the atmosphere that creates heavy rains, flooding, and more extreme hydrological cycle that can be linked to catastrophic fires in the Amazon, California, and more recently Australia (Cheng, et al., 2020).

For more reading on the topic, please refer to the resources used in this blog post:

Cheng, L., and Coauthors, 2020: Record-setting ocean warmth continued in 2019. Adv. Atmos. Sci., 37(2),137−142 Retrieved from: https://doi.org/10.1007/s00376-020-9283-7

Houser, K. (2020, January 14). The Ocean is Warming at a Rate of 5 Atom Bombs Per Second, Scientists Warn. Science Alert. Retrieved from https://www.sciencealert.com/the-ocean-is-warming-at-a-rate-of-5-atom-bombs-per-second-says-study?fbclid=IwAR1oYIMVl2Vls6NT976A4rbD32ASIpCSf7iV7mjNpgUop_YZP8IQHLnsSe4

Bindoff, N.L., W.W.L. Cheung, J.G. Kairo, J. Arístegui, V.A. Guinder, R. Hallberg, N. Hilmi, N. Jiao, M.S. Karim, L. Levin, S. O’Donoghue, S.R. Purca Cuicapusa, B. Rinkevich, T. Suga, A. Tagliabue, and P. Williamson, 2019: Changing Ocean, Marine Ecosystems, and Dependent Communities. In: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate [H.-O. Pörtner, D.C. Roberts, V. Masson-Delmotte, P. Zhai, M. Tignor, E. Poloczanska, K. Mintenbeck, A. Alegría, M. Nicolai, A. Okem, J. Petzold, B. Rama, N.M. Weyer (eds.)]. In press. Retrieved from https://www.ipcc.ch/srocc/chapter/chapter-5/