Hurricanes, floods, droughts, wildfires. You’ve undoubtedly heard all these things and more being attributed at least in part to global warming. But why would a rise in Earth’s average temperature cause all these other kinds of effects? We’ll explore the answer in this section by focusing on the expected consequences of global warming, the evidence that shows these consequences are occurring, and how these consequences are likely to affect us in the future.
It’s worth noting that, in this process, we’ll in some sense be changing our focus from global warming to climate change . That is, even though the two terms are often used interchangeably, there is a subtle difference between them. Global warming refers to the fact that Earth’s global average temperature is rising. Climate change refers to the many local and regional changes in Earth’s climate that are occurring as a result of the warming. Of course, the local and global are deeply intertwined. As we will see, both local and global consequences have the potential to do great damage to people around the world.
Section Learning Goals
By the end of this section, you should be able to answer the following questions:
- What are the major consequences of global warming?
- How do scientists predict future consequences of global warming?
- How will climate changes affect you and others around the world?
Before you continue, take a few minutes to discuss the above Learning Goal questions in small groups or as a class. For example, you might discuss what (if anything) you already know about the answers to these questions; what you think you’ll need to learn in order to be able to answer the questions; and whether there are any aspects of the questions, or other related questions, that you are particularly interested in.
Discussion
Margaret Thatcher on Global Warming
By now, you hopefully understand that global warming is a scientific fact, not a political opinion. Nevertheless, in recent years there have been some people who have tried to politicize the issue. This makes it worth going back to the global leader who made the first major speech to the United Nations raising the alarm about global warming. This leader was the conservative British Prime Minister Margaret Thatcher, who is considered to have been one of the founders of modern conservatism. Read this excerpt from her 1989 speech, then discuss the questions that follow:
“What we are now doing to the world … by adding greenhouse gases to the air at an
unprecedented rate… is new in the experience of the Earth. It is mankind and his
activities which are changing the environment of our planet in damaging and
dangerous ways.”
— British Prime Minister Margaret Thatcher, Nov. 8, 1989 (speech to the United Nations)
- Notice that she says that we are “adding greenhouse gases to the air at an unprecedented rate” and that this is “new in the experience of the Earth.” Is that an accurate reflection of what we know about the rising greenhouse gas concentration? Explain.
- She continues by saying that the cause of the environmental (climate) change is “mankind and his activities,” and she says this in a way that implies it is a clear fact, not an opinion. How do you think she knew this back in 1989?
- Suppose that someone tries to tell you that only liberals believe that global warming is real. How could you use Thatcher’s statement to counter their claim?
- Bonus: Watch or read the transcript of Margaret Thatcher’s full 1989 speech to the United Nations. (Click here for the video or here for the transcript.) Discuss her overall message about the importance of environmental protection. Do you think the world has followed her advice in the decades since she gave the speech?
This discussion could in principle be done at almost any point during this chapter, but we suggest it here at the beginning of Section 7.2 because it gives students a chance to review what they’ve already learned about the basic science and gives you a chance to help them understand that the partisanship that often surrounds this issue is a fairly recent invention. In particular, the fact that arch-conservative Margaret Thatcher was the first major global leader to speak out about global warming on the international stage should prove that it was not some kind of liberal idea, but rather an idea based on science. Notes:
- (1) Students should recognize that her statement is accurate based on what they learned in Section 7.1. The ice core record shows that the current rise in carbon dioxide concentration is occurring much faster than any natural rises in the record. And while we can’t completely rule out that a similarly fast rise has happened at some point in Earth’s past (perhaps associated with a mass extinction), what we are doing is clearly different from the norm of what Earth experiences.
- (2) This question is designed to get students thinking about how things would have appeared to people studying the issue back in 1989. The answer can be traced to two key facts. First, the basic 1-2-3 science has been known far longer than that; students should recall that the science of the greenhouse effect was first studied back in 1856 (by Eunice Newton Foote), and the 1-2-3 science was well-understood by early in the 20th century. Second, as students saw in Figure 7.1.3–1, the data show that global warming was clearly underway by the early 1980s. So, by 1989, the scientific case for global warming was quite clear, and politicians (like Thatcher) who paid attention to science were already aware that there was no scientific doubt about the basic facts. Fyi: If you are wondering why Thatcher was one of the first politicians to understand the science, it is probably because she was a scientist herself. Before entering politics, she graduated from Oxford with a degree in Chemistry and worked for a few years as a research chemist.
- (3) This, of course, is the main point of quoting Thatcher. If global warming had been some kind of liberal idea, it would not have been a staunch conservative like her that first raised the alarm about it at the United Nations. In fact, you can find many other conservative leaders making similar statements, a few of which are highlighted in Dr. Bennett’s online Global Warming Primer.
- (4) The full speech is worth watching or reading, as she clearly explains her depth of concern for the environment and discusses concrete actions that she believes should be taken in response. There are many lines in the speech that you might want to focus student attention on; one favorite is “We can’t just do nothing.” Most students are likely to conclude that we have not followed her advice very well in the ensuing decades, as what we’ve done has arguably been much closer to “nothing.”