The Two-Mile Time Machine
Global Warming? Psh. Abrupt climate change–with rapid cooling and resultant drought–is what we really need to worry about.
Of course, the former is likely to cause the latter, so I guess we should worry about both.
A Brain for All Seasons drew much of its inspiration from this book. So I picked it up to get familiar with the background data. It’s an ice-core scientist explaining the many varied tactics that are used to determine past climate conditions, and how they all dovetail. Note that much of this data was just gathered and interpreted in the 90’s, so don’t be surprised if it’s different than what you learned in school. It also doesn’t seem to have gotten much press coverage–climatologists don’t speak of “global warming” anymore. The concern is very large, very rapid climate swings from warm and wet to cold and dry–they have happened dozens of times in the past, and the very warm, stable period of the last 11,500 years (a familiar number if you’ve read Jared Diamond on the foundations of civilizations) has been a complete anomaly.
The author is a pleasant writer, and very good with analogy. He explains the technology at a high level, so you don’t feel bogged down, but you still get a good feel for how this stuff is determined. Scientists use ice and seabed cores from around the world, as well as geologic evidence. They then check for a remarkable variety of gases, isotopes, chemicals and minerals. From this they can tease out the effects of the earth’s wobbly axis, uneven orbit, solar activity, continental drift, and biological outputs. They form a number of overlapping cycles that were predicted, then discovered, in the data. It seems amazing that they can determine all of this, but his repeated dual-data charts that show incredible correlations from different types of sources half the world away from each other are very convincing.
One interesting “key” to climate shifts is the Atlantic currents. Apparently right now warm salty water moves from the equator to Greenland, then cools (leaving Europe nice and warm) and then sinks, to flow back. The problem is that many things can go wrong–including an excess of less-dense fresh water from Greenland’s glaciers caused by global warming–to halt these currents, or at least shorten how far North they go. These changes can happen very rapidly, within just a couple of years, and have an enormous impact on the entire globe’s climate.
Almost of all the book is about the past–explaining what happened with the earth’s climates, why, and how we know all of this. There are just a few pages at the end that speculate about the future, and he’s very clear that it’s speculation. His summary is this: there are too many variables for our models to determine exactly when the climate will shift, or exactly how far. But a cursory glance at the past makes it clear that there is a very reasonable chance that it will shift very far very soon–and that it is prudent to start alleviation efforts now, as well as continue to work on our models so we can make better predictions.