Earth's energy imbalance
Topic: Solar Radiation, Heat Balance and Temperature · NCERT: Beyond NCERT
Meaning
The Earth's energy imbalance is the gap between the energy the Earth absorbs from the Sun and the heat it sends back to space. Over long periods these two used to be nearly equal. Now greenhouse gases trap more outgoing heat, so the Earth absorbs more than it gives off. The gap is roughly 0.5-1 W/sq m. This extra heat builds up in the climate system and warms it.
Example
Satellite data show that the imbalance about doubled between 2005 and 2019. About 90% of the extra heat goes into the world's oceans, including the Indian Ocean, so ocean heat content keeps rising.
Don't confuse with
- Heat budget of the Earth: the NCERT heat budget is a balanced model. Out of 100 units of incoming sunlight, the Earth returns 35 by reflection and 65 by radiation, so it neither warms nor cools. The energy imbalance is the small, present-day departure from that balance.