This category can only be viewed by members. To view this category, sign up by purchasing Annual subscription, 12 Month Subscription or Monthly subscription.

Alternative view on climate change

Joe Shimmin (UK) Before you start shouting at your magazine, don’t worry, you’re not going to read that I think climate change isn’t happening or that human beings aren’t contributing to it. However, I am going to try to show that the version of climate change that we are always being shown may not be all that we should be thinking about. If you look at the timescale over which human-influenced climate change has been happening – and compare it with geological time – it is such a tiny period. However, people do not live over geological time periods, so it is natural that we concentrate on the present, with little regard for the past. In fact, with today’s human influenced climate change taking up all of the limelight, anyone would think that climate change was solely a human invention and that before the industrial revolution, the climate had been stable. But this is not the case. Fig. 1. A Map of Europe during the last glacial maximum. Blue areas are covered by ice. Green areas are land. White shows oceans and seas. In the event of a glaciation, could the influx of people migrating from the north be mitigated by the growth of the land masses due to a drop in sea level? Picture credit: Kentynet. A quick glance at Figs. 2 and 3 shows massive changes in average global temperature across the millions of years of geological time. The y axis of the graph shows change in average … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Geopark Shetland: A journey through the 35th European Geopark

Allen Fraser (UK) In September 2009, the Shetland Islands were awarded the accolade of becoming the thirty-fifth European Geopark. This is fantastic news for the isles. It acknowledges the importance of Shetland’s incredible geology and creates opportunities to promote it to an international market and develop partnerships with other members. When visiting, the best place to start your journey into Shetland’s ancient past is at Shetland Museum, in Lerwick. Here, displays take you back into the mists of time, revealing vanished landscapes and the amazing events behind them. All across Shetland, the rocks and landscapes tell an endless story – of oceans opening and closing, of mountain building and erosion, of ice ages and tropical seas, volcanoes, deserts and ancient rivers, of land use, climate change and sea level rise, and of minerals and miners. Around 360mya, a walk through where Lerwick is now, would have meant a wade across fast-flowing rivers, in a climate like that in Death Valley, California. How do we know? Well, if you take a stroll around Lerwick, and walk from the Knabb to the Sletts and out to the Sands of Sound, you can see for yourself. Here, flat-lying beds of thick, buff-coloured sandstone begin to acquire rounded pebbles and cobbles of pink and white quartz. These sandstone beds tell us that fast flowing rivers once deposited their loads in the area and that flash floods occasionally scoured the riverbed, leaving trains of far-travelled cobbles and pebbles embedded in the sandy layers. These rivers … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Mammoths in the freezer

Adrian Lister (UK) As palaeontologists, we are used to relying on the preserved hard parts of extinct organisms – shells, bones, teeth and so on – to reconstruct their appearance and adaptations in life. The reconstruction of soft tissue relies upon our knowledge of related living forms, plus clues such as the scars of muscle attachments on bones or shells. Exceptions include body outlines preserved in the fine-grained sediments of Lagerstätte, such as in the Eocene of Messel (Germany) or the Cambrian Burgess Shale (Canada); or, even more rarely, organisms preserved in 3D, of which the most familiar source is Tertiary amber. Among mammals, the most celebrated case of exceptional preservation is provided by the carcasses preserved in permafrost in Siberia (Russia), Alaska (USA) and the Yukon (Canada), at localities lying almost exclusively north of the Arctic Circle (Lister and Bahn, 2007). Almost all date to the last glaciation, with radiocarbon dates typically in the range 50 to 10,000 years ago. Species from which partial or whole carcasses have been recovered include bison, horse, wolverine, woolly rhinoceros and, above all, the woolly mammoth. The reason for the preponderance of these is unclear, although it may partly be a matter of reporting bias, other species being considered less interesting or less valuable when discovered by local people. Even so, not more than a dozen or so complete or largely complete mammoth carcasses have been recovered to date. While Siberian natives have doubtless been finding these remains for millennia, the first carcass … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Fossil forests in the freezer

Stephen McLoughlin (Sweden) South of the craggy limits of Patagonia, Africa and Tasmania, and beyond the piercing gales of the roaring forties and the furious fifties, lies Antarctica – the last great continent on Earth to be explored. Straddling the South Pole, it lies frozen in a winter that has lasted millions of years. Today, only a few plant species more robust than mosses eke out a harsh existence on its warmest fringes. The bitter cold and screaming katabatic winds (a katabatic wind is one that carries high density air down a slope under the force of gravity) that drain off the continental interior mean that few plants and animals can survive in Antarctica year-round. However, this has not always been the case. Through much of deep time, it has not been the ‘white continent’ but a land of green forests and lush swamps. This forested landscape provided habitats for a wide range of terrestrial animals for most of the past 400 million years. The continent’s central location within the ancient southern supercontinent of Gondwana also meant that it held an important role in the exchange of plants and animals between the southern lands. Fig. 1. Map of Antarctica showing the Permian-Triassic basins. Early clues Little was known about Antarctica’s geology or fossil heritage until ‘the heroic era of exploration’ began to unlock the continent’s secrets in the 1800s. Some of the first explorers to realize that vegetation once clothed Antarctica’s landscape were the members of Captain Robert Scott’s team, … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Can the end-Permian mass extinction be attributed to a single, catastrophic event?

Robert Broughton (UK) The end Permian mass extinction occurred 251mya and marked the end of the Palaeozoic era. The loss of life is currently estimated to consist of 95% of the marine fauna and around 70 to 77% of the known terrestrial fauna (where the fossil record is inevitably less complete). This article will provide an overview of the many events and processes that played a part and a discussion whether they can all be attributed to a single, root cause. Reef evidence At this time, the landmass was united into the single, super-continent of Pangea, surrounded by warm shallow seas with abundant reef systems. This extensive reef fauna supported a variety of suspension feeders (for example, crinoids, rugose and tabulate corals, and so on), which were the most heavily hit by the extinction event, with all the known corals dying out. Modern scleractinian corals only appeared in the Triassic and there is a considerable gap in the coral fossil record at this time. Other reef inhabitants, such as the last phillipsid trilobites also became extinct. All these creatures were sessile or relatively immobile inhabitants of the reefs that occupied a relatively narrow zone on the continental shelf. This habitat must have been destroyed almost globally by a number of factors, but importantly, the single shelf margin around Pangea meant there was no other shallow reef environment for the fauna to migrate to. Fig. 1. Reef evidence. Tectonic activity The single continent of Pangea was always doomed to split apart. … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Colossal tortoises: Climate change and the evolution of Europe’s largest ‘modern’ reptiles

Benjamin Kear (Australia) and Georgios Georgalis (Greece) Most people are familiar with the famous giant tortoises of the Galapagos Islands – isolated oddities evolving in the absence of predators on a remote tropical paradise. However, as little as 5mya, continental landmasses (including Europe, Africa and India) also had their own species of giants. However, these were nearly three times the size of their modern cousins, probably close to the mass of a small car, and would have rivalled some dinosaurs for being among the most colossal reptiles of all time. Fig. 1. A life-size reconstruction of the European gigantic tortoise Cheirogaster as displayed in the University of Athens Palaeontological and Geological Museum. This model represents a massive individual of a carapace length of around 2m and was based on finds from Pikermi, near Athens, and the island of Lesvos. The best preserved gigantic tortoise fossils (as opposed to the merely ‘giant’ ones) have been found in Mediterranean Europe, particularly France, Greece and Spain, and were described in the scientific literature as early as 1877. Yet, despite an impressive chronicle of discoveries, the inter-relationships between these different kinds of gigantic tortoises are far from adequately understood. The present, albeit tentative, consensus is that there are at least three separate lineages, all of which achieved maximal body size at about the same point in geological time. Cheirogaster, the genus found in Europe, has a long fossil history stretching back some 50mys to the Eocene and includes up to 11 species. It is … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

History shows current climate change is normal

Tim Ball (Canada) Those who I refer to as ‘the new deniers’ keep trying to repair the infamous climate “hockey stick”. This is a term coined for a chart of temperature variation over the last 1,000 years, which suggests a recent sharp rise in temperature caused by human activities. The chart is relatively flat from the period AD 1000 to 1900, indicating that temperatures were relatively stable for this period of time. The flat part forms the stick’s ‘shaft’. However, after 1900, temperatures appear to shoot up, forming the hockey stick’s ‘blade’. Those who support the hockey stick focus on the blade, but it was not the major issue originally. The bulwark claim of the anthropogenic global warm (AGW) hypothesis and the objective of the stick are that current global annual average temperatures are the warmest ever. This meant that the upturn of the blade in the twentieth century was only relevant if it was higher and steeper than any previous record. Earlier warm periods were not a threat in the first reports of the Intergovernmental Panel on Climate Change (IPCC). Their mandate required that they only look at human causes, which they interpreted to mean the industrial period. However, as experts who were denied participation in the IPCC process began to examine what was said, they identified earlier warmer periods, especially the Medieval Warm Period (MWP) dating from 900AD to 1300AD, and more rapid temperature increases. Fig. 1. Temperatures for Europe plotted against the 20th century average. (Source: Based … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.