I found the descriptions of many of those explorations extremely hard to read. That's no criticism of the writing. In fact, it may be a compliment to the writing. It was so evocative of the dark and tight places that he was visiting that I found it very claustrophobic and oppressive. I have to admit I skimmed quickly through some of those sections.
The author visits a great variety of such underground features from sinkholes in Slovenia to a nuclear-waste containment site in Finland and sea caves in Norway. His explorations in Greenland document the effects of global warming, including the fact that some of the things that are being brought to the surface by melting ice are detrimental to the environment and to human life on the planet.
One of the most depressing facts encountered by Macfarlane is that everywhere he goes he finds garbage about which he expresses his disgust.
"Among the relics of the Anthropocene, therefore, will be the fallout of our atomic age, the crushed foundations of our cities, the spines of millions of intensively farmed ungulates, and the faint outlines of some of the billions of plastic bottles we produce each year – the strata that contain them precisely dateable with reference to the product-design archives of multinationals. Philip Larkin famously proposed that what will survive of us is love. Wrong. What will survive of us is plastic, swine bones and lead-207, the stable isotope at the end of the uranium-235 decay chain."Occasionally, Macfarlane's prose is a bit over the top, not to say purple, but for the most part, it is exceptional. He is extremely talented in describing scenes, events, and scientific concepts in ways that are easily understandable for laypeople.
My favorite part of the book was the discussion of the underland communication system of trees and other plants. It has long been known that plants do communicate but mostly it has been observed as an above-ground phenomenon. It turns out that there are a lot more complicated communications going on under the surface. Roots of trees, for example, communicate to each other specific information about the state of the tree's health and about the environment. They even are able to provide sustenance to a fellow tree through the root system. And all of this is facilitated with the help of fungi called mycorrhizae.
“The term ‘mycorrhiza’ is made from the Greek words for ‘fungus’ and ‘root’. It is itself a collaboration or entanglement; and as such a reminder of how language has its own sunken system of roots and hyphae, through which meaning is shared and traded. The relationship between mycorrhizal fungi and the plants they connect is ancient – around 450 million years old – and largely one of mutualism. In the case of the tree–fungi mutualism, the fungi siphon off carbon that has been produced in the form of glucose by the trees during photosynthesis, by means of chlorophyll that the fungi do not possess. In turn, the trees obtain nutrients such as phosphorus and nitrogen that the fungi have acquired from the soil through which they grow, by means of enzymes that the trees lack.”Fascinating! Macfarlane should write a book just about this subject. I'd certainly read it.
My rating: 4 of 5 stars