Ice Age

it was while watching the fighting that he suddenly had a flash of insight which showed him the way around the mathematical logjam that had been holding him up. It was a classic example of the way the answer to a problem you have been struggling with can pop into your head once you stop looking for the solution.

When reversals happen, they take place in less than 10,000 years (perhaps much less), so they show up sharply in the geological record; but once a particular orientation of the field is established, it may last for millions of years, or only for a few tens of thousands of years. The most recent reversal happened about 780,000 years ago, but the Ear

He was one of the first people to appreciate the major influence of the great ocean currents on climate, and was the first person to work out the link between the trade winds (essentially driven by convection in the atmosphere stirred up by the Sun heating the surface of the Earth) and the flow of these currents, pushed by the winds. He reasoned th

We think that it is normal to have ice at both poles of our planet. After all, there has been ice there for longer than there has been human civilization. But in the long history of the Earth, polar ice caps are rare, and having two polar ice caps at the same time may be unique. Indeed, it may be the presence of those polar ice caps which has made

It is concluded that changes in the Earth’s orbital geometry are the fundamental cause of Quaternary ice ages. A model of future climate based on the observed orbital-climate relationships... predicts that the long-term trend over the next several thousand years is towards extensive northern-hemisphere glaciation.

In the most extreme example of this chauvinistic approach, geologists set the start of the present epoch, the Holocene, at the beginning of the present Interglacial, 10,000 years ago. This is completely unjustified, since there is no evidence that the present Interglacial marks the end of the Ice Epoch that has persisted for the past few million ye

Since the temperature at the bottom of the sea hardly changes, even during the switch from an Ice Age to an Interglacial, this was the definitive proof that the main influence on the oxygen isotope composition was indeed the advance and retreat of the ice sheets on land, and that the isotopes were recording the pulsebeat of global climate change.

Coffee (black) was served by Milankovitch’s wife promptly at ten o’clock, and occupied just ten minutes before it was back to work. Lunch at one was followed by a short siesta and a cigar, then more calculations until six, when work ceased for the day. A stroll before dinner, which was a leisurely meal taken at eight, where the family discussed the

As we mentioned earlier, given the present day geography of our planet—the distribution of the continents and oceans—the natural state of the Earth is in a full Ice Age. Koppen was correct in highlighting the importance of summer warmth in influencing the advance and retreat of the ice in the Northern Hemisphere. But, in a sense, he, too, got the a