The Emerald Planet

by David Beerling

Plants are sometimes considered as the less exciting bit-part players in the story of evolution. David Beerling puts them squarely centre-stage as he charts their role in the last 542 million years in The Emerald Planet. Over the course of geological time plants have helped to shape the world we live in, and this book looks at the subtle and often surprising ways they have terraformed the planet and altered Earth's atmosphere.

The prehistoric landscape would have seemed pretty alien to human eyes, not least because there was a time when plants had neither leaves nor flowers. The author explores the reasons why leaves may have taken so long to evolve, and the evidence for early atmospheres that were very different from our own.

Although plants may have played a pivotal role in changing the climate and atmosphere, they don't get all the glory. During the Carboniferous era there were giant insects and amphibians, as well as super-sized horsetails and clubmosses. The book explains how the levels of oxygen and other gases varied over time, allowing the development of megafauna, and how we know about this so many years later. This book is densely packed with facts, but they're not difficult to grasp and David Beerling's anecdote-filled accounts keep the story lively.

Mass extinctions make everything more dramatic, of course, and the book features quite a few. Starting with the end Permian mass extinction the author looks at the usual suspects for the devastation. He examines volcanoes and meteor strikes, as well as other possible causes such as ozone depletion and suffocation. This is still a controversial topic. It puts current ecological crises into perspective, and the research that's gone into this section is extremely thorough.

This is a wide-ranging book that delves into the history of science as well as current knowledge. There's an account of Captain Scott's ill-fated expedition to the Antarctic, and the geology his team uncovered. This leads into a discussion of the much warmer climate of past eras, when the poles weren't covered with vast ice sheets. Imagine temperate forests where now there's nothing but frozen wastes: details like this help to communicate the author's clear enthusiasm for palaeoclimatology.

We don't often think of grass as sinister. But the rise of grasslands around 8 million years ago is connected to a feedback cycle of forest fires, and the way grasses have encroached into new territories seems ominous. It's one example of how plants, given enough time, can have a huge impact on the world we live in.

This book shows how life has adapted to a wide range of different atmospheres and climate extremes. It's tempting to take these fascinating facts and use them as an excuse to be unconcerned about climate change in the modern world. But David Beerling ends on a cautionary note, demonstrating the dangers of making assumptions based on what happened in the past when modern plants have evolved into somewhat different organisms.

The Emerald Planet is gripping because it's full of urgent issues like global warming and extinction events that threaten to affect us all. It manages to be scholarly and deep, as well as broad in its subject matter, and it's all presented in a very readable style. The book might read a little faster if the copious notes were on the same page they are mentioned on instead of stuck at the back of the book, but that's minor. Even though this is mostly about plants, it's a natural history book with real meat on its bones.