Even small rises in the global average temperature have risks.  The complication is that we don’t perceive the full impact of a 2°C increase of temperature.  It’s like pollution in the seas and oceans: it’s not all at the surface so we don’t see it, we pay less attention and it becomes less important.  But just because we don’t see it doesn’t mean its not there.

Interesting graphs are the rise of heat content of the “global ocean”:

Fig 1.

From Skeptical Science, J Cook created from JA Church et al 2011.
See also Eu Environ Agency’s 
Ocean heat content  

Fig 2.

From Cheng et al 2019

The graph on the left shows that the heat content of the oceans (the blue area) has become HUGE ! So a problem is that we measure “global warming” by the increase of atmosphere’s temperature (equivalent to the orange part), which does look deceivingly small, but the amount of heat is tremendously large.  The oceans’ temperature increases due to the heat flow from the warm air in the atmosphere in contact with the water – if so much heat has accumulated in the oceans over the last ~40 years, imagine how long it’ll take for the temperature to come back down to “normal” levels.

The graph on the right is a recent study which confirms the  increase of heat over the years and shows a similar amount of heat in the oceans.

If we look at the evolution of the total amount of energy stored in the surface waters (700 m) of the oceans, we arrive at a variation of a phenomenal level of 3.6 x1022 cal (15 x1022 Joules) more ! ? 

This amount of heat corresponds to:


  1. 10 billion bombs from Hiroshima or “five Hiroshima-size atomic bombs exploding every second” (from article in the Guardian below)
  2. 300 times the amount of energy consumed in the world in one year;
  3. the total energy of the Sun that reaches the Earth in 10 days;
  4. 4 times the (potential) energy reserves of all fossil energy estimated in the world (oil + gas + coal).

An article from the Guardian by J Abraham puts these findings into perspective:


  • 2018 was the hottest year ever and the the last five years were the hottest on record
  • the oceans absorb more than 90% of the heat in the atmosphere resulting from greenhouse gases, so this is where the the earth’s heat accumulates and where global warming needs to be measured
  • the rate of ocean warming reflects an unimaginable energy transfer, the explosion of “five Hiroshima-size atomic bombs exploding every second”

What are the consequences ?  The following are a few: ?, ?

  1. depletion to the point of extinction of many kinds of marine ecosystems, species & life, such as corals and fish
  2. rising sea level (see the video “How Earth Would Look If All The Ice Melted”)
  3. warmer oceans are:
    • changing weather patterns: more powerful storms, as hurricanes are charged with heat-energy from the oceans
    • heavier rainfall and increased flooding
    • rising sea levels, since water expands as it warms
    • increasing ocean acidity, since higher concentrations of CO2 in the air is absorbed in the water

Find out more:

Have a look to see if the country you where you live has has heated up over the years, check out our post on “Temperature anomaly