The History of Global Climate Change, part 1

We used many resources for this article. The most important was "The Discovery of Global Warming" at the site of the American Institute of Physics. It is detailed, objective, and well written, and we strongly encourage people to go to the site and read all of it.

Before we begin, let’s clear up a question that confuses a lot of people. Is it global warming or global climate change? Actually, the two terms refer to different things. And both are involved in the current debate over greenhouse gases.

Global warming refers to a change in overall atmospheric temperature brought about by changes in concentration of the so-called "greenhouse gases." You can learn more about greenhouse gases by clicking this link. The theory of global warming has a long history, as we will see. We’ll leave it to you to decide whether or not you believe it has been proven.

Global climate change is anything that causes extreme changes to weather patterns across the entire world, and in particular changes that might be so severe as to change human society.

There are three questions we face today:

• Is global warming happening?
• Is it being caused by mankind’s use of fossil fuel?
• Will it lead to global climate change, and if so, what will be the consequences?

Global climate change has happened before. We know that millions of years ago most of the earth was much hotter than it is today. More recently, much of the earth was covered with ice. We know that strong volcanic eruptions have thrown enough dust and debris into the atmosphere to change weather patterns across the planet, and we suspect that collisions with large objects from space have caused sudden, dramatic changes in weather across the planet, perhaps even resulting in species becoming extinct.

We have worried about mankind’s actions causing global climate change before. During the Cold War, we feared that nuclear war could result in a form of global climate change known as nuclear winter.

The connection between global warming and global climate change is strongly suspected. But the details, while frightening, can only be guessed at. Let’s see how we got to where we are today.

America has alternately debated and ignored greenhouse gases and global climate change for the past twenty years. Scientists around the world have been studying both of them, with growing concern, for centuries.

The idea that certain gases in the atmosphere could capture heat radiating from the earth was first proposed by French scientist Joseph Fourier in 1824. He called this the "greenhouse effect." In 1859, The English scientist John Tyndall, working to explain how the Ice Age could have occurred, confirmed that water vapor, carbon dioxide and methane could absorb and reflect heat from infrared radiation, effectively trapping it in the atmosphere. He also speculated that even small changes in atmospheric concentration could have a profound effect on the overall atmospheric temperature.

By the way, if you follow up this story by doing some research on greenhouses, you will discover that Fourier wasn’t correct when he coined the term "greenhouse effect." Greenhouse gases do trap the sun’s heat; so do the glass buildings we use to grow flowers through the winter. But while the result is similar, the process by which it happens is completely different. Fourier thought the atmosphere was a thin sheet, like a pane of glass. We know today that it is miles high, with many layers. Science often works like this; we discover the results first, then gradually uncover the processes behind them. The term "greenhouse gas" didn’t come into wide use until the 1960s. It works well enough to help people understand what’s going on, so it looks like it’s here to stay.

The first person to connect climate change and man’s use of fossil fuels was Swedish scientist Svante Arrhenius, in 1896. However, Arrhenius thought that global warming and high greenhouse gas concentration was a good thing, because it would help prevent another ice age! Times, and fears, change.

While most scientists accepted Arrhenius’ models, few believed that mankind could possibly produce enough emissions to have a significant impact on something as vast as the earth’s weather. It should be noted that climate scientists have agreed for more than a century about the role that greenhouse gases play in atmospheric temperature. The debates have centered on how important mankind’s role could be, and what changes to the earth’s weather would result from an overall warming.

Ironically, for much of the next fifty years scientists studying global climate change were primarily concerned with the possibility of another ice age. This scared them as much as global warming scares scientists today. So there was considerable public reaction to a theory published by Maurice Ewing and William Donn in 1956 which speculated that earlier ice ages had been caused by migration of the poles, and that another ice age might be imminent. Spurred by the public’s concern, governments directed more money into climate science, and scientists worked to develop better models to explain how weather works.

The late 1950s saw the emergence of computers as a tool to improve models, measurements and processes. As new and better data became available, attitudes began to change about the significance of mankind’s effect on atmospheric greenhouse gas. A paper published by Roger Revelle and Hans Suess in 1957 is seen by many as a turning point in the debate. Up until then, most scientists had assumed that excess carbon dioxide simply dissolved into the oceans, negating the impact of industrial emissions (carbon dioxide is by far the most common of the greenhouse gases.) Revelle and Suess proved that this didn’t happen, and that the carbon dioxide released into the atmosphere stayed there in every-increasing concentrations.

The term "global warming" was used for the first time in articles about this research. "Global warming" is actually a journalistic, rather than a scientific, term.

At the same time, people were starting to think in new ways about how mankind’s actions could affect the earth. The atomic bomb, and later the hydrogen bomb, had demonstrated with frightening clarity how powerful and destructuve human technology could be. Books, in particular Rachel Carson’s Silent Spring, published in 1962, made millions aware of the far-reaching effects of industrial and agricultural pollution, and gave rise to the environmental movement in the late 1960s.

Within the community of scientists who studied the weather, consensus was already building, as more and more evidence pointed to the profound and lasting effect of even small changes in greenhouse gas concentration in the atmosphere. It is important to note that "consensus" means something different to the scientific community than it does to most people. We think of "consensus" as meaning a simple majority. To scientists, "consensus" has not been reached until a substantial majority are in agreement and a substantial amount or research reaches the same conclusion. Scientists rarely agree on anything, so scientific consensus is a powerful affirmation of an idea.

With industrialization growing worldwide, and greenhouse gas emissions increasing exponentially, fear of a new ice age gave way to a new, and wholly opposite, fear. In 1965, in the President’s Science Advisory Committee, presented their concerns about the possible consequences of global climate change brought about by global warming. In 1970, Carroll Wilson, a leading scientist and activist, brought 40 scientists together for the first time to study, discuss and publicize their concerns about the threat of global warming. Was it possible the world was already well on the way down a path which ended at a truly frightening place?

Unfortunately, the science of weather is bafflingly complex…ask any weatherman…and we are only today beginning to develop the tools and the mathematical models needed to study and predict it accurately. A whole new field of mathematics has grown out of the study of weather patterns: it’s called chaos theory. So it is little surprise that the scientific community had a difficult time communicating their fears to the public. They had some solid data, but also much speculation and many competing theories. Much of the data was in the form of mathematic calculations and computer models which only a few specialists could understand.

The media, as it often will, seized on the most extreme speculations and highlighted the disagreements. The public found the speculations unrealistic and the science confusing. This marked the point where the public perception of global climate change, and the perception of the scientists who study it, diverged. This split remains to this day. The public is skeptical and divided; the scientific community is not. Despite what you may have heard from some corners, the scientific community has been in agreement about global climate change for almost forty years.

Greenhouse gases became a "hot topic" in the 1970s, but global warming had nothing to do with it. Chlorofluorocarbons (CFCs) absorb infrared radiation, which makes them a greenhouse gas. They also destroy ozone, and this is what made them front page news. CFCs were used in aerosol spray cans and refrigerators throughout the world, and years of constant emission had damaged the ozone layer that protects earth from the harmful ultraviolet rays of the sun. Government action was demanded and taken, and CFCs were partially banned in America, despite a publicity campaign by the chemical industry to undermine the science and sway public opinion (sound familiar?) The partial ban wasn’t enough, however. In 1983 the "ozone hole" over Antarctica was discovered, and America’s ban would eventually grow to a global one.

CFCs forced people to recognize that the actions of one individual, multiplied by the millions of people on earth, could have a global impact. If something as trivial as spritzing your hair could damage the ozone in the stratosphere, what other common activities might be doing damage? And if it was possible to undo the damage simply by giving up spray cans, what else might we have to give up in the future to protect the earth?

Another event of the early 1970s gave Americans a wake up call about their deeply ingrained dependence on fossil fuels: the OPEC oil embargo. For the first time, people began to consider the benefits of the emerging "green" technologies of solar and wind power.

The 1980s were a period of political conservatism in the United States, and global warming faded from public discussion. Yet environmental issues continued to make the news, and most of the stories were not good. Acid rain, toxic waste and species extinction were stark reminders of how much damage human technology could do, and that environmental problems didn’t go away just because the political winds had changed.

Within the community of weather scientists, concern was growing that global warming was no longer a possibility, but instead was already happening; 1980, 1981 and 1983 were each record years for global temperature.

Global warming returned to the public’s attention with a bang in 1988, when Jim Hansen, a climate scientist who had done some of the most advanced computer modeling, told a congressional committee that global warming was "a certainty" and could happen within a decade. The fact that he made this prediction during the long, hot summer of the hottest year in recorded history made the media take notice.

And thus, the global climate change debate began in earnest. Things were about to get very interesting. Read part 2 to find out what happened next.