If you want to understand the history of mankind, you should especially look at shifting continents and changing climates, writes Lewis Dartnell in his book Origins. That produces a lot of interesting things, but he sometimes sees a causal connection too easily.
Why does the Earth look like this today? How did continents, oceans, mountain ranges and deserts form? And to what extent has this earthly history determined the course of human history? These are the questions that British professor of science communication Lewis Dartnell poses as the starting point for his book Origins:How the Earth made us. He seeks the answers in geological and climatic processes that have shaped both the earth and mankind.
Planetary factors
Dartnell rightly believes that the history of mankind cannot be explained solely by the conscious decisions and actions of (groups of) people. Explaining why agriculture developed in one place while people continued to hunt and gather elsewhere has everything to do with the specific local conditions. You need wild plants that you can eat and grow, you need suitable soil and also the right climate. Each and every one of these is beyond your control and is entirely determined by what Dartnell calls 'planetary factors'.
An example of an important planetary factor is the periodic change in the shape of the Earth's orbit around the sun. That orbit is ellipsoidal, but varies in the degree of stretch. This in turn influences the distance from the sun and thus the temperature on the earth's surface. Then there are also periodic variations in the position of the earth's axis and in the spinning of the earth around its own axis. These also have a direct influence on the amount of sunlight that falls on parts of the earth and therefore on the temperature. Dartnell uses these so-called Milankovitch cycles to clearly explain how the Earth's climate has changed over the past hundreds of millions of years and what influence this has had on the conditions and the landscape on Earth.
Shrinking ice caps
Another influential phenomenon is plate tectonics:the movement of the different parts of the Earth's crust. Over the past few billion years, the face of the Earth has changed beyond recognition. Floating, colliding, fracturing and abrasive land masses have created not only mountain ranges and volcanoes, but also lakes, seas and oceans. Thanks to these continuous changes, the landscape and everything that lives there has become so varied. Dartnell is very skillful in translating major geological and climatic changes from millions of years ago into the landscape as we know it today, and it works very well. You don't get a dry, chronological listing of events. There is, however, a clear link between, for example, the growing and shrinking ice caps during the various ice ages and the current landscape.
In the same way, Dartnell also discusses the origin of the oceans, seas and major waterways, as well as the evolution of the plant and animal families that make up our daily diet. Dartnell shows why certain rocks and the raw materials we extract from them, such as metals, coal and oil, occur in specific places on earth. He describes it all in an accessible and appealing way, so that you can clearly see that there is a direct line between those large, uncontrollable events from millions to billions of years ago and the environment in which we could arise and still operate today.
Shortcut
Unfortunately, Dartnell can't resist the temptation to emphasize again and again how direct that line is. That is also a pitfall of his approach and of other Big History -writers who try to capture and explain everything in one big grasp. Of course, we cannot separate our history from the history of the earth. And yes, as the title of his book also claims, the earth 'made' us. But that does not mean that everything you see now can be traced back one-to-one to a geological or climatic cause.
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For example, Dartnell shows that there is a similarity between the locations of the coal seams in England and Wales and the modern constituencies where the Labor Party has been winning elections for years. Well, it's not surprising that the party has (or had) a lot of support in areas where many miners used to live, but Dartnell puts it as if it were a causal relationship. At the same time, in a footnote, he undermines his own claim by stating that this principle does not apply to Scotland. In the same way, he links the composition of the strata in a strip of constituencies in the southeastern United States to the dominance of the Democrats in those areas. Because:fertile land, so cotton plantations, so many slaves, so now Democratic voters.
These short-sighted lines of reasoning are really unnecessary and weaken Dartnell's argument rather than add to it. The history of the earth and how it has influenced and still does our own little history is exciting and interesting enough. Fortunately, Dartnell's book mainly offers that story.