Image by Zdenec Machacek
This review is by Isabel de Berrie
This book by bat scientist Johan Eklöf is an accessible yet authoritative account of the under-recognised problem of light pollution.
Drawing on his own extensive experience as a researcher as well as other sources, Eklöf demonstrates how the human desire to banish the darkness of night leads to interference with the delicate sensory apparatus of manifold plant and animal species, affecting critical processes such as hunting, mating, and sleeping.
He details how sophisticated sensory systems which have evolved over long periods to respond to the timing, strength, wavelength, and directionality of light can be completely befuddled by artificial light sources.
In some of Eklöf’s accounts of how an artificial light can hijack the brain of an animal which becomes dazed, failing to hunt, mate or navigate, I can’t help thinking of how humans seem irresistibly drawn to the artificial glow of screens, turning our attention to them at the expense of essential life activities, watching them through the hours when we would otherwise sleep.
The first section doesn’t pull any punches: the author outlines just how much human activity is lighting up the Earth during what would otherwise be hours of darkness.
He suggests that satellite pictures of the illuminated Earth are the strongest symbol of the Anthropocene – a period of the Earth’s development in which it is affected by human activity.
He emphasises the severity of the consequences, including mass die-offs of multiple species of insects essential to ecosystems, as well as some impacts on humans of living under constant illumination.
Part II explores the evolution of vision across species, from the very first eyes up to present times, and goes into detail about how creatures active in the twilight and at night-time use their senses.
There are interesting discussions of wide-ranging creatures (I particularly enjoyed the parts on glow worms and ghost moths), as well as the ways in which plants respond to night. (In this chapter you can also learn how to trick a poinsettia into blooming twice).
Alongside the fascination of remarkable plant and insect processes, and anecdotes about magical experiences of nature, there are sobering examples of how completely these processes can be devastated by the introduction of bright human light.
Part III provides some history of astronomy and delves more into human relationships with the darkness and the night sky.
Eklöf mentions unexpected experiences of natural light and demonstrates that night is so much more than total darkness, and humans too can appreciate the subtlety of night-time illumination, including “zodiacal light,” if we only dare to keep the lights off.
You may well leave this section with a renewed urge to view things by moonlight.
In Part IV, Eklöf turns to some human efforts to reclaim the experience of darkness, and suggests some benefits beyond the normally cited health benefits, such as the psychological freedom to speak openly which is found in some events that take place in darkness.
He finishes with the call to “carpe noctem” (seize the night) before it’s too late.
Throughout the book he has recognised that the human urge to light our path is something that would be difficult to eradicate, and only asks that we consider what light we truly need, especially since we are often preventing our night vision from becoming active.
He invites us to embrace our inner rhythms and discover the wonders of the night sky and inform ourselves about how plants and animals need the light, as well as spreading the word about its importance.
This book could be an engaging read both for those who enjoy learning about science and those who are new to the topics discussed.
It’s arranged in short chapters which could be read one at a time in any order. Eklöf takes several detours to explain more general ideas concerning sensory apparatus, evolution and biology, and manages to do so in a way that isn’t too tedious for those who may already have basic familiarity with these topics.
He offers personal anecdotes without getting bogged down in them. This book raises the alarm while also offering hope and inspiration to think positively about darkness, which for so long has served as a negative symbol.
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