Latent Signs of Change: The Events That Led to Earth Day 1970

By Jojo Picone ’23

When drilling below the surface of a glacier, the ice core can reveal years of change preserved in time. While 1970, the year of the first Earth Day, was a watershed moment for environmental policy in the United States, a history of human-related environmental damage goes back further, deeper in the ice cores.

50 years ago, Senator Gaylord Nelson founded Earth Day (1970) as a way of bringing focus to environmental concerns, energized by the spirit of the Civil Rights Movement and the Vietnam War Protests. Before 1970, without policies like the Clean Water Act regulating discharge into water sources and without an Environmental Protection Agency (EPA) to enforce such policies, air and water in the United States had grown increasingly polluted. Although the first Earth Day was centered around improving air and water quality, the goal of April 22 has always been environmental awareness. Every year, people all around the world keep the spirit of Earth Day alive by celebrating this planet and looking to its future.

I spoke with Director of the Climate Change Institute, Dr. Paul Mayewski, about the climate history leading up to the first Earth Day. Starting around 18,000 years ago with the Last Glacial Maximum (LGM), the ice sheets were at their thickest, and they encased a significant percentage of the planet. After the LGM, Earth’s climate warmed and the glaciers began to retreat. During this post-LGM warming, there was a rapid swing into a final cold period called the Younger Dryas, after which climate variability decreased, and we entered modern Holocene climate. As Dr. Mayewski notes, “It’s only in the last 10,000-8,000 years that [human civilization] begins to look something like what we experience today.” From the 1400’s through to the mid-1800’s there was a cool period called the Little Ice Age (LIA). Dr. Mayewski described this event as “probably the most prominent cooling of the last 9,000 years,” and the LIA might have signified the onset of the next glacial cycle. However, in a short time, humans drastically increased the rate of CO2 entering the atmosphere, altering the natural cycle of the climate.

Beginning in the late 1700’s, the Industrial Revolution brought unprecedented pollution, mostly related to manufacturing, without environmental protections in place. At the time, many people were aware of the health hazards posed by this pollution, such as respiratory problems from breathing in pollutants found in smog. But, because large cities came to be associated with a new life and economic growth, the pollution at the time was associated with progress and not with a risk for the future. Describing the findings of a research expedition to Greenland he led, Dr. Mayewski described how, “You really see the levels of sulfur, mostly from dirty coal, increasing around 1900.” Because sulfur in the atmosphere can hide the effects of greenhouse gases, cooling the climate, few people in the early 1900’s were aware that the steep increase in carbon emissions from automobiles and factories could lead to increased global temperatures.

With the start of World War II in 1939 came a period of worldwide environmental neglect. In the United States, above ground nuclear bomb testing, industrial weapons manufacturing, and the use of leaded gasoline created harmful and radioactive pollutants. These toxic substances can remain in the Earth’s climate system for an extended time. The aftermath of World War II led to a time of social change and reinvention in the United States.

Unlike in the times of the Industrial Revolution, workers in the United States were receiving more protections, and the grime of cities was no longer representative of prosperity. In the 1960’s, there was growing environmental awareness, and a push towards conservation of resources. In 1963, the Clean Air Act was passed, as people by then were able to witness the long-term consequences of air pollution. As for the water quality, several rivers throughout the United States had grown solid with sludge. In 1969, the largest oil spill in U.S. history at the time took place off the coast of Santa Barbara, and in Ohio the Cuyahoga River famously caught fire, an image which shocked the population. Throughout the decades preceding Earth Day, freedom of expression was a powerful tool, with the peaceful activism of the Civil Rights Movement and the youthful energy of the Vietnam War Protests inspiring legislation and change. Therefore, when Earth Day was founded in 1970, the world was ready to embrace this environmental movement.

Since that first Earth Day, scientists have discovered that Earth’s climate can change abruptly and it is growing more unstable. As Dr. Mayewski told me, “what we experienced in the last 50 years is not necessarily what we will see in the coming decades.” Even though past climate information may not be enough to predict what the future climate will look like, we can still look to the past for hope. 50 years ago, when enough people became aware that their environment was in danger, they organized to create the first holiday celebrating the environment and they pushed for new legislation. Now, with environmental problems which were previously unimagined, sharing scientific information about our climate with the people we know can reshape the future of this planet, and the society we live in another 50 Earth Days from now.

To learn more about the current atmosphere and climate, The Climate Change Institute has several resources: 10Green indicates the levels of harmful air pollutants in any region of the United States, and The Climate Reanalyzer gives weather forecasts and compares the current climate against past climate measurements. Another useful resource is the National Atmospheric Deposition Program.