Ice age cycles directly linked to changes in Earth's orbit for the first time
It has been assumed that changes in the Earth's orbit around the sun are responsible for the ice age cycles. It is now clear how this works.
(Image: Matt Perko/UC Santa Barbara)
An international research team may have discovered which changes in the Earth's orbit around the sun were responsible for the alternation between ice ages and warm periods over the past 2.5 million years. This was reported by Cardiff University, which led the study. The pattern of orbital changes fits so well with recent climate history that it is hard to believe it has been overlooked so far, says study leader and geoscientist Stephen Barker. At the same time, it is so clear that the team was even able to determine that the next ice age should actually begin in 10,000 years – were it not for man-made climate change.
Human influence too great
It has long been known that the current ice age is linked to changes in the Earth's orbit, writes the research team. So far, however, it has not been possible to identify the orbital parameters that are most important for the beginning and end of the ice age cycles. This is also due to the fact that it is difficult to precisely date ice ages that occurred a long time ago. However, the team has now managed to do this by analyzing different measurement data on the expansion of the ice sheets and the temperature of the water deep in the oceans. As a result, they found a change in the Earth's orbit that preceded an ice age and one that was associated with its end. They explain the details in the journal Science.
The team was able to confirm the connection for the past 900,000 years. If humanity had no influence on the climate, the next cold period with extensive ice sheets would have to begin in 10,000 years. However, it is "very unlikely" that this will actually happen because humanity has already released so much COâ‚‚ into the atmosphere that the climate has deviated from its normal course, adds co-author Gregor Knorr from the German Alfred Wegener Institute. The team now wants to determine how the climate should actually develop over the next 10,000 to 20,000 years and what effects human-induced climate change will have in such a distant future.
(mho)