{"id":2450,"date":"2018-08-29T18:54:24","date_gmt":"2018-08-29T18:54:24","guid":{"rendered":"https:\/\/globalchangeecology.com\/?p=2450"},"modified":"2018-08-29T18:55:45","modified_gmt":"2018-08-29T18:55:45","slug":"book-recommendation-the-sixth-extinction-an-unnatural-history-by-elizabeth-kolbert","status":"publish","type":"post","link":"https:\/\/globalchangeecology.com\/2018\/08\/29\/book-recommendation-the-sixth-extinction-an-unnatural-history-by-elizabeth-kolbert\/","title":{"rendered":"Book recommendation: The Sixth Extinction: An Unnatural History by Elizabeth Kolbert"},"content":{"rendered":"

Have you ever heard of the Panamanian golden frog? Or the white-plumed antbird? Probably you\u2019ll never hear about them because they are on the edge of extinction. Fragmentation, the excessive use of land and climate change are just a few of the factors that are causing a major extinction event. Right now. Right here.<\/p>\n

There have been five major mass extinction events in the history of earth. Extinctions of single species has always happened, but these five big extinction events are characterized by a loss of 75% or more of all species. The first mass extinction event<\/b> occurred in the End Ordovician, 444 million years ago, where 86% of all species<\/b> were lost. This event was probably triggered by a short and severe ice age, killing most of the \u2013 at the time mainly aquatic \u2013 species. The second extinction <\/b>occurred in the Late Devonian, 375 million years ago. 75% of the species<\/b> were lost. The culprit this time: Newly evolved land plants that stirred up the earth and released nutrients in the ocean, which for its part caused algae blooms, using up oxygen and harming ground-dwellers such as trilobites. The third mass extinction<\/b>, also known as \u201cthe great dying\u201d occurred in End Permian, 251 million years ago. Several natural catastrophes \u2013 occurring at the same time and causing each other in a domino effect \u2013 killed nearly all life on Earth: 96% of all species<\/b> vanished. Some groups of species never evolved again. The forth mass extinction happened 200 million years ago, at the End Triassic<\/b>. Even though 80% of all species<\/b> were killed, a clear cause could never be found. The fifth mass extinction<\/b> \u2013 66 million years ago at the End Cretaceous \u2013 might be the most famous one: Volcanic activity, climate change and an asteroid\u2019s impact ended the era of dinosaurs on Earth. But also, other species suffered: 76% of all species went extinct. (1<\/a>)<\/p>\n

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One witness of a great mass extinction event: The Tyrannosaurus Rex. (Image: By Connie Ma from Chicago, United States of America – Sue, the world’s largest and most complete dinosaur skeleton.Uploaded by FunkMonk, CC BY-SA 2.0, https:\/\/commons.wikimedia.org\/w\/index.php?curid=20207230)<\/figcaption><\/figure>\n

But soon, we might have to add another mass extinction to this list. The sixth mass extinction<\/b>, happening in the Anthropocene, right now. How many percent of the species on Earth will be gone this time? Some authors think the sixth mass extinction event has already begun, others say, we are on the edge. Clear is, we are observing currently a rapid extinction of many species due to human activity: Habit destruction, overexploitation, new diseases, invasive species and climate change are just some of the driving factors.<\/p>\n

To define a mass extinction event, one has to look at the extinction rate, specifying how many species go extinct in \u201cnormal periods\u201d. These so-called \u201cnatural background extinction rates\u201d can be estimated by going through fossil databanks. With there help it can be for example estimated that under \u201cnormal\u201d conditions every 700 years one mammal species will go extinct. This changes when a mass extinction event occurs. The palaeontologists Anthony Hallam and Paul Wignall write that \u201ca mass extinction is an extinction of a significant proportion of the world\u2019s biota in a geologically insignificant period of time\u201d. (2<\/a>) And even if we don\u2019t know whether we are witnessing an extinction event equal to the former five events, one thing is clear: Species are vanishing, faster and more thoroughly than during the last 66 million years.<\/p>\n

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The great auk. The last individual was killed in 1844 in Iceland. (Image: John Gerrard Keulemans [Public domain], via Wikimedia Commons, https:\/\/commons.wikimedia.org\/wiki\/File:Great_auk_with_juvenile.jpg)<\/figcaption><\/figure>Journalist Elizabeth Kolbert addresses this issue in her book The Sixth Extinction: An Unnatural History. <\/i>Visiting places where the ongoing extinction is most evident, she accompanies many scientists in different fields \u2013 from the Amazon to Scotland, from small Italian islands to Cincinnati \u2013 and writes about their findings. The indications for an ongoing extinction event can be found everywhere.<\/p>\n

In the first part of the book, Kolbert addresses some species that have already disappeared: The mastodon, an extinct mammoth species, the great auk, the last individual being killed in 1844 in Iceland, and the ammonites, for their part witnesses of a mass extinction event. Kolbert tells the story how in 19th century certain natural scientists discovered there must have been species roaming the earth that went extinct \u2013 a blasphemous thought! Hadn\u2019t god created all species, perfectly adapted to their environment? How could some species just have vanished? It took quite some time until the thought of the extinction species caught on\u2026<\/p>\n

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The mastodon. It’s bones gave the first hint that species vanished from Earth. (Image: Charles R. Knight [Public domain], via Wikimedia Commons (https:\/\/commons.wikimedia.org\/wiki\/File:Knight_Mastodon.jpg))<\/figcaption><\/figure>In the second part she visits scenes where causes of extinction are most evident. The Italian island where scientists investigate the acidification of the oceans, melting away calcareous shells. The Amazon, where fragmentation causes severe damage and where an enormous project is going on for almost 50 years: The Biological Dynamics of Forest Fragments Project (BDFFP), aiming to find out how fragmentation influences biodiversity. The trees in the Peruvian cloud forest, that are forced to \u201crace\u201d uphill to cope with rising temperatures due to climate change. The amphibians all over the world, dying in thousands because of one fungus, transported everywhere by humans. The list seems nearly endless.<\/p>\n

The Sixth Extinction: An Unnatural History <\/i>is quite an eye-opener, covering all important processes that are contribution to the ongoing extinction. And even though the book is dealing with a serious topic, Kolbert writes in a way that leaves you not thoroughly depressed. Now you know the Panamanian golden frog and the white-plumed antbird. And the more people know about their fate, there is a chance that other species don\u2019t have to go the same way.<\/p>\n","protected":false},"excerpt":{"rendered":"

Have you ever heard of the Panamanian golden frog? Or the white-plumed antbird? Probably you\u2019ll never hear about them because they are on the edge of extinction. Fragmentation, the excessive use of land and climate change are just a few of the factors that are causing a major extinction event. Right now. Right here. There […]<\/p>\n

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