In this video by Yale Climate Connections, Jørgen Peder Steffensen, an expert in ice core analysis from the Niels Bohr Institute, explains how the Earth can become hotter yet simultaneously plunge Europe into an ice age and North America into ice or drought. It's a matter of distribution.
Here are some points that stunned me in the video:
- In the last 1 million years there have been 10 ice ages. Each ice age lasted about 90,000 years.
- Ice ages aren't uniformly cold. Far from it! Steffensen says, "Inside an ice age the climate is extremely unstable, and you have this sequence of abrupt climate changes [semi-cold to very cold] that happen basically from one year to the next."
- In-between ice ages are interglacial periods of milder, more stable climate that last about 10,000 years. We're in an interglacial period right now. It's already 11,000 years old.
- Earth can have an ice age in one place and be hot elsewhere. Ice cores indicate that when Greenland has an ice age, Antarctica is warm -- and vice versa.
- Earth's current mild climate is due to a global distribution pattern of ocean currents and pressure systems that keep temperatures mild and rainfall moderate.
- The global distribution pattern can change abruptly. We don't know where the trigger is, though we do know our emissions add fuel to the fire.
As Steffensen says, "The climate does not play nice all the time,"
Learn more at Yale Climate Connections: Humans experimenting with climate's 'playing nice'
(screenshot and video from This Is Not Cool with Peter Sinclair, Yale Climate Connections)