For the Yukon ice-patch people who are so generous with their time and knowledge C E
Contents Introduction Frozen in Time 6 Ice Patches Mystery on the Mountain 8 Ice Patches Time Detectives at Work 10 Ice Patches Hunters Arrows and Atlatls 12 Ice Patches Vikings on the Mountains 14 Glaciers Lost on the Glacier 16 Glaciers Traveler from the Past 18 Glaciers Glacial Changes 20 Permafrost Lords and Ladies in the Ice 22 Permafrost Children of the Gods 24 Permafrost A Frozen Zoo 26 Permafrost Mammoths and People 28 Cryosphere Slip-Sliding Away 30 Glossary and Further Information 32 Timeline 33 Index 34
INTRODUCTION Frozen in Time Deep in the massive ice sheet that covers the continent of Antarctica there is ice that’s been around longer than modern humans Way longer It froze about 2 7 million years ago almost a million years before our extinct relatives a people called Homo erectus were huddling around flickering fires as protection against giant hyenas and enormous shambling bears Our species Homo sapiens didn’t arrive on the scene until a mere 200,000 years ago That’s the power of cold Once water turns to ice it can stay frozen for a very long time Anything that’s trapped in the ice also stays frozen and preserved kind of like the veggies in a kitchen freezer The frozen places of the world are melting as Earth’s climate changes And as they melt the past is revealed 6
have been surprised and delighted by these unexpected discoveries even as they scramble to find and preserve the material before it thaws and turns to dust These relics of the past have stories to tell stories we’re still trying to understand and stories we haven’t even imagined Earth as a Greenhouse When the sun’s energy both heat and light hits Earth some is absorbed and some bounces back into space But Earth’s atmosphere contains a few gases such as carbon dioxide and methane that stop the energy from escaping These heat-trapping gases are called greenhouse gases and a lot of them come from human activities such as farming industry and the burning of fossil fuels oil gas coal The more greenhouse gases there are in the atmosphere the more Earth warms up and the climate changes And Earth has plenty of frozen water snow glaciers ice patches high in the mountains and the ice that covers lakes and oceans in the world’s cold regions In parts of the world there’s even permanently frozen ground called permafrost beneath the surface layer of soil Altogether those frozen places make up the cryosphere CRY-oh-sfeer a word derived from the Greek word kryos which means cold Some of the ice lasts for just a season but some is hundreds or even thousands of years old And that ice can contain amazing surprises tools weapons clothing and even the bodies of people who lived long ago Frozen along with them are bits of the world they lived in such as plants animal remains even layers of dust These are all clues that can tell us what that world was like But now global climate change is warming Earth’s air ground and water and some of those frozen clues are melting out of the ice The study of this once-frozen material is called glacial archaeology even though it refers to all of the cryosphere not just glaciers Archaeologists and other scientists 7
