Environment & Biodiversity

The oceans absorb 90% of human-caused global warming, according to a new study

According to the study published in the journal Earth System Science Data, the ocean has absorbed over 90% of the warming that has happened in the last 50 years, with the remaining heat absorbed by the land, cryosphere, and atmosphere.

Earth’s energy balance: A quick recap

  • It is the difference between the quantity of energy received from the Sun and the amount of energy sent back into space.
  • It is also referred to as the radiation budget.
  • The majority of the energy received by Earth from the Sun is in the form of visible light and ultraviolet radiation.
  • This energy is absorbed by the Earth’s surface and atmosphere, which then emits infrared radiation back into space.
  • The balance of incoming and outgoing radiation is critical for keeping the Earth’s temperature and climate stable.
  • Any imbalance between the two has the potential to cause global warming and climate change.

The following are the study’s key findings: Accumulation of Heat

  • According to the analysis, manmade emissions amassed 381 zettajoules (ZJ) of heat on the planet between 1971 and 2020.
  • This equates to a heating rate of about 0.48 watts per square metre (Earth Energy Imbalance, or EEI). The difference between incoming and outgoing solar radiation is referred to as the EEI.
  • According to the research, approximately 89% of the accumulated heat is held in the ocean, 6% on land, 1% in the atmosphere, and approximately 4% is available for melting the cryosphere.


(1) Land Heat Accumulation

  • Heat collected on land raises ground surface temperatures, which may promote soil respiration and result in the release of carbon dioxide.
  • Depending on the climatic and meteorological conditions and causes, increased soil respiration will most likely reduce soil water.

(2) Inland Water Bodies and Permafrost Thawing

  • Since 1960, heat storage in inland bodies has grown to about 0.2 ZJ. It was roughly 2 ZJ for permafrost thawing.
  • Heat accumulation in inland water raises lake water temperatures, creating ideal circumstances for algae blooms.
  • According to the experts, the heat content of permafrost might release methane and carbon dioxide into the atmosphere.

(3) Ocean and Troposphere heating

  • According to the revised estimations, the upper ocean (0-300 and 0-700 metres depth) has absorbed a significant portion of the heat.
  • Between 2006 and 2020, ocean warming rates in the 0-2,000 metre depth reached a new high of about 1.03 watts per square metre.
  • Because of increasing heat accumulation, the troposphere is also warming.

(4) Cryosphere heating

  • From 1971 to 2020, the cryosphere (the frozen water element of the Earth system) accumulated about 14 ZJ of heat.
  • Half of the uptake was caused by the melting of grounded ice, while the other half was caused by the melting of floating ice.
  • The Antarctic Ice Sheet supplied around 33% of total cryosphere heat gain, with Arctic sea ice coming in second at 26%.
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