How much energy is global warming adding to the atmosphere and oceans?

It’s a surprisingly large amount, but before we get to the numbers, let’s consider exactly what is happening. As we discussed in this earlier box, a planet that is neither warming nor cooling must return exactly as much energy to space as it absorbs from the Sun. Note that this is true even if there is a very strong greenhouse effect. For example, Venus is very hot due to its extremely strong greenhouse effect, but it is not getting any hotter because it is in balance between absorbed energy and returned energy. On Earth, the fact that human activity is strengthening the greenhouse effect means that our planet is slightly out of balance. That is, Earth is getting warmer because it is absorbing slightly more energy from the Sun that it is returning to space.

Scientists have two different ways of measuring the energy imbalance. One way is by measuring the increasing heat content of the oceans, and the other is from satellite measurements of the amount of infrared light that Earth is emitting back to space. Both give the same basic answer: At the current rate at which human activities are increasing the concentration of carbon dioxide and other greenhouse gases, we are causing the total energy of the atmosphere and oceans to increase by approximately 250 trillion joules each second . To put this in more familiar terms, that is the equivalent of, for example:

• The energy that would be added by detonating four Hiroshima-size atomic bombs each second (see this web site for details).
• The energy that would be released by 500,000 lightning bolts each second.
• Enough energy to maintain two powerful hurricanes at all times.
• Enough energy to power almost 3,000 strong tornadoes each day.

With that much energy being added to the atmosphere and oceans, it should not be at all surprising that we would have noticeable consequences. Indeed, you might wonder why the consequences aren’t even greater than they are, and the answer is that most of the energy is going into the gradual warming of the oceans and atmosphere, rather than into things like extreme weather events or melting of ice.