Global Climate Change

Turning Knowledge Into Action

David Kitchen

• Publisher: Routledge
• Year: 2016
• ISBN:
  9781315506630
• Topic: Biological Sciences
• Subtopic: Environmental Conservation & Protection
• Edition: 1

The science of climate change is a complex subject that balances the physical record and scientific fact with politics, policy, and ethics - and is of particular importance to the geosciences. This thoughtfully crafted new text and accompanying media encourage non-science majors to practice critical thinking, analysis, and discourse about climate change themes. Taking a cross-disciplinary approach, acclaimed educator and researcher, David Kitchen, examines not only the physical science, but the social, economic, political, energy, and environmental issues surrounding climate change. His goal: to turn knowledge into action, equipping students with the knowledge and critical skills to make informed decisions, separate facts from fiction, and participate in the public debate.

PART 1
THE EVIDENCE: IS THIS NORMAL?

CHAPTER 1: SO WHAT’S UP WITH THE WEATHER?

CHAPTER 2: THE EVIDENCE: OBSERVING CLIMATE CHANGE

Parts of New Jersey and New York City were devastated in late October 2012 by a 4 meter (13 foot) storm surge that was driven ahead of Hurricane Sandy. It is not yet clear if climate change will affect the frequency and intensity of future hurricanes, but increasing global sea level will enhance the risk of all future storm surges.

Earth’s climate is changing.
Climate records are being set across the world as heat waves, droughts, floods, snowstorms, tornados, and hurricanes impact the lives of millions of people. There are now clear signs of changing climate on every continent across the globe. As the human and financial costs of extreme weather rise we must understand why global climate is changing and work hard to mitigate its worst impacts. Geological evidence has uncovered a record of continuous and natural climate change, but the extreme weather we observe today is different because none of the usual forces that drive climate change appear to be responsible. Recent climate change appears to be the consequence of a precipitous increase in the emission of heat-trapping greenhouse gases from deforestation, industry and agriculture. Levels of carbon dioxide in the atmosphere have risen by 40% since preindustrial times, and are now higher than at any time during the previous 800,000 years. Computer models project that a level of emissions this high will accelerate climate change until we reduce emissions from all sources. Climate change is a global problem that requires a global solution. Chapter 1 introduces important concepts about weather, climate, and climate change and chapter 2 presents physical evidence that regional climate is changing rapidly across the globe.

Hurricane Katrina was a powerful Category Five hurricane with winds of 160 mph. Each year hurricanes transfer enormous amount of energy from the tropics to higher latitudes, helping regulate Earth’s climate. There may be a link between the intensity of hurricanes and higher ocean temperatures, driven in large part by climate change and global warming.

CHAPTER 1
“So, What’s Up with the Weather?”

Introduction

Almost every day, some claim or counterclaim about climate change and global warming hits the headlines. For most of us this is very confusing. Some people consider every storm, drought, heat wave, and record temperature further evidence for global warming; others dismiss these same events as natural climate variation. Isn’t everyone looking at the same data? How can the same facts be interpreted in such different ways?

When the interpretation of scientific data makes it imperative that we change the ways we create and use energy, the origin of these data becomes controversial and politically-charged. Before we undertake any action that will have a long-term impact on society, we need to understand how and why global climate changes. The geological record shows us that climate change is a normal part of Earth’s history, and while most scientists conclude that recent changes in global temperature and climate are due to the emission of human-made (anthropogenic) heat-trapping greenhouse gases, a small but vocal minority disagrees. In order to project the future impact of anthropogenic emissions accurately, we must understand the different factors that have driven climate in the past and how small changes in global temperature will affect Earth’s climate today.

Learning Outcomes

When you finish this chapter you should be able to:

• Discuss how global temperature has changed over geological time

• Identify some of the principal factors that control global climate over different timescales

• Describe the recent historical temperature record

• Determine possible causes of recent changes in global temperature

• Understand how climate models can be used to project climate change

• Evaluate the possible impact of human activity on the atmosphere

Weather and Climate

Before we begin to discuss climate change it is important to discuss the difference between weather and climate. Weather is experienced from day to day. One day can be hot and dry and the next cool and wet. Climate, on the other hand, can be related to the statistical probability that any day during the year will be similar to the same day in previous or following years. In Virginia, the winter temperatures are often close to freezing, but the weather on any one day is very unpredictable. The temperature in January can reach as high as 25°C (78°F), but based on weather records, it is very likely that cool air, rain, sleet, and ice will soon return because the climate of Virginia is characterized by cool, wet winters and hot, humid but relatively dry summers. What is the climate like where you live? Is there much variation in weather from year to year?

CHECKPOINT 1.1 ► In your own words, describe the difference between weather and climate.

Is the Climate Changing?

Over the past 100 years, global temperature has been rising at a rate that is slow in terms of a human lifespan but rapid enough to worry climate scientists (Figure 1.1b). Climate varies naturally—within limits. Occasional extreme weather events and temperature records do not prove that climate is changing, but scientists have discovered that the past few decades have experienced a statistically significant increase in the number of record heat waves and a decrease in the number of record cold spells (Figure 1.1a and Figure 1.1b). (Chapters 2 and 7 will investigate this evidence in more detail.) It is clear that Earth’s climate is changing, but we need to find out why and what is likely to happen in the future.

How Stable Is the Cl...