Scientist in Germany have revealed that the next ice age may be delayed by over 50,000 years. The reason cited for this delay is the greenhouse gases put in the atmosphere by humans.
- Scientists have analysed the trigger conditions for a glaciation, like the one that gripped Earth over 12,000 years ago.
- The shape of the planet’s orbit around the Sun would be conducive now, they find, but the amount of carbon dioxide currently in the air is far too high.
- At its maximum extent, the last glaciation witnessed a big freeze spread over much of North America, northern Europe, Russia and Asia. In South, a vast expanse of what are now Chile and Argentina were also iced up.
How a glaciation is initiated?
Changing nature of its orbit around the Sun is the fundamental factor determining what dips Earth into an ice age.
- The passage around the star is not a perfect circle and over time our planet’s axis of rotation also rocks back and forth.
- These movements alter the amount of solar radiation falling on the Earth’s surface, and if a critical threshold is reached in mid latitudes in the Northern Hemisphere then a glaciation can be initiated.
Findings:
- Confirmations in their modelling also show the role played by the concentration of greenhouse gases in the atmosphere.
- Earth probably missed the inception by only a narrow margin a few hundred years ago, just before the industrial revolution took hold.
- An interglacial climate would probably have been sustained anyway for at least 20,000 years, and, very probably, for 50,000 years, even if CO2 had stayed at its eighteenth century level.
Comments:
Andrey Ganopolski from the Potsdam Institute for Climate Impact Research said: “In theory, the next ice age could be even further into the future, but there is no real practical importance in discussing whether it starts in 50,000 or 100,000 years from now.” He also added: “The important thing is that it is an illustration that we have a geological power now. We can change the natural sequence of events for tens of thousands of years.”
Prof Eric Wolff from the University of Cambridge, UK, said: “There have been previous papers suggesting that the next ice age is many tens of thousands of years away and that the combination of seasonal solar energy at the latitude where an ice sheet would form, plus CO2, is what determines the onset of an ice age. But this paper goes much further towards quantifying where the limits are.”
“It represents a nice confirmation that there is a relatively simple way of estimating the combination of insolation and CO2 to start an ice age.”
Prof Chris Rapley, from University College London, added: “This is an interesting result that provides further evidence that we have entered a new geological [Epoch] – ‘The Anthropocene’ – in which human actions are affecting the very metabolism of the planet.”
