“The radiative forcing of the CO2 we have already put in the atmosphere in the last century is … the equivalent in energy terms to almost half a billion Hiroshima bombs each year.” Radiative forcing is a measure of how out of balance the Earth’s energy budget is. “When there’s more energy radiating down on the planet than there is radiating back out to space, something’s going to have to heat up.”
Because he is a professor of Geology, he gives a geologic example.
Think volcanoes are powerful? Our impact is much greater.
Frustrated fliers in the eastern states will know that volcanoes vent a lot of gas and particulate matter from the interior of the Earth. Over geological time, that material is returned to the Earth through natural mineralization, but we know that it can and does impact climate.
So how do we compare?
Our best estimates place human industrial emissions of sulfur dioxide and CO? at five and 100 times natural volcanic emissions, respectively.
Yet, he also recognizes another significant change and that is to the oceans. He notes evidence that the oceans are growing warmer. More significant to the atmospheric degradation that marks the Anthropocene is ocean acidification and the corresponding lack in an ability to take up the growing CO2 excess that we indiscriminately spew.
- The geology of the planet: Welcome to the Anthropocene (economist.com)
- Dot Earth: Perceiving the Anthropocene (dotearth.blogs.nytimes.com)
- The Anthropocene: A man-made world (economist.com)
- Geologists press for recognition of Earth-changing ‘human epoch’ (guardian.co.uk)