iving things have aver age temperatures For humans normal body LTE temperature is 98 6 °F 37°C For most birds average body temper ature is a little higher from 104 to 108 °F 40° to 42 °C Planets while not living EC entities nevertheless also have average temperatures For Venus the hottest planet in the solar system the average surface tem perature is about 867 °F 464 °C hot enough to melt lead The aver I age surface temperature of Mars is about 82 °F 63 °C The aver N age temperature on Earth is about N 60 °F 16 °C Or at least that's the current figure Scientists have I observed and noted that over the past 100 years the temperature of I our planet has been rising And just as an above normal body temperature is a warning sign of illness a growing number of sci entists are asserting that the rising surface temperature on Earth a
INTRODUCTION Shrinking habitats such as that for this polar bear and her cubs is one possible outcome of an increasingly hotter planet Scientists predict that if the Arctic sea ice continues melting as projected the polar bear population of 20so may be one third of what it is today Johnny Johnson Riser Getty Images
GLOBAL WARMING phenomenon known as global warming is a global warning sign we need to heed In this book readers will learn about the greenhouse effect and how it is connected to global warming Much like plants in a greenhouse all of us on Earth are encased in an atmosphere that traps heat from the Sun Carbon dioxide water vapor methane and other gases which do the trapping have been responsible for keeping the planet warm enough for life to thrive The issue before us all now though is that these so called green house gases are increasing some believe dramatically and with them their heat trapping properties Such an increase and its impact on global climate are of great concern Why the increase As readers of this book will discover with the onset of the Industrial Revolution some 200 years ago machines began making the products people used to make by hand That development was foll lowed by advances in transportation such as the advent of the steam engine the car and the airplane These machines running on fossil fuels emit exhaust sharply raising the concentrations of atmospheric gases that had prior to 1800 or so been relatively stable for thousands of years Today about 90 per cent of the power used to run machines
INTRODUCTION comes from the burning of fossil fuels To further complicate matters the widespread cutting down of forests means that trees nature's own carbon dioxide eaters CO is used by trees to make their food are being removed from an equation that they might otherwise help to balance Whetheror not global warming is a natural fluctuation or a human caused phenomenon has been debated in the media though sci entists now widely agree that humans are indeed the cause of the past century's steep temperature rise Evidence collected from thermometers for roughly the past 150 years as well as paleoclimatic data taken from glacial ice cores tree rings and other sources show that the surface temperature on Earth is indeed rising Glaciers are melting animal habitats are dwindling and weather events such as hurricanes typhoons and heat waves seem to be on the rise Read on to discover the science behind the debate the effects rising temperatures are having and are pro jected to have and what the world is doing in
