Introduction

It can be hard to grasp the impacts of climate change. Understanding it involves data sets, complex vocabulary, and confusing political views. How can we make sense of the information that is out there? One way is to look at how environmental changes since 1800 are related to industrialization and enormous increases in the global population.

The Industrial Revolution in the nineteenth century changed how we work, where we live, and how many of us there are. Population increased because of better machinery and more food production. More people moved to cities for factory jobs. New cultural and economic networks of exchange connected and further globalized the world.

By the mid-1800s, industrialization spread throughout the world. European nations and the US benefitted the most. These wealthy, industrialized nations extracted resources from Africa, Asia, and Latin America to fuel their own growth. By the end of the nineteenth century, everyone was affected by this system in one way or another.

Population Explosion

We know industrial acceleration and globalization caused population growth. In 1803, the global population reached 1 billion for the first time. It grew to 2.5 billion in 1950, 5 billion in 1987, and 8 billion today. Much of that growth can be linked to the effects of industrialization, namely food production.

There were also periods when the population fell, which were caused by the two world wars and the influenza outbreak of 1918. Industrialization was a factor in these population drops. New technology made wars deadlier and helped germs spread faster. However, innovations in medicine, transportation, and communication—all products of industrialization—let the population recover faster than it ever had in the past.

Table 1: Total Population by Region (in millions, rounded)¹

Increased Urbanization

After 1800, the areas where population increased the most were cities, as the table below shows. In 1800, no part of the world had more than 13 percent of its population living in cities. By 2008, the percentage of people living in urban areas is more than in rural areas.

Table 2: City Life: Percentage of Urban Population by Region

Urbanization has had generally negative effects on health. Disease and pollution increased as more people lived closer together. Over time, innovations in medicine and sanitation took care of some of these problems.

Advances in medicine also increased life expectancy. In 1770, people lived to about 29 years. Only 100 years later, in 1870, this only increased to 30 years. By the early twenty-first century, life expectancy was up to 71 years. These numbers vary around the world. Developing economies, such as those in Africa and Southeast Asia, have seen smaller increases in life expectancy.

Environmental Changes

The increases in population and life expectancy may make it seem as though everything got better over time, but that is not the case. The industrial world depends on fossil fuels such as coal, petroleum, and natural gas. Burning them releases carbon dioxide (CO₂) into the atmosphere.

For the first 200 years of industrialization, CO₂ levels did not pass 300 parts per million (ppm). But the carbon dioxide level increased dramatically after World War II. Currently, the level is at 421 ppm. High levels of CO₂ cause global temperatures to rise. We are already 1.5 degrees Celsius above what’s normal. The rise in CO2 and global temperatures cause ice at the poles to melt, making sea levels rise. Humans and animals living near coastal areas are endangered by rising sea levels. Nearly half of the human population currently lives within 100 miles of a major body of water.

It is not just species on land that are put in danger. There have also been notable CO₂ increases in the Earth’s oceans.

“The global ocean absorbed 34 billion metric tons of carbon from the burning of fossil fuels from 1994 to 2008—a fourfold increase of 2.6 billion metric tons per year when compared to the period starting...1800 to 1994” (NOAA).

These increases make the oceans more acidic, endangering marine life. Shellfish are finding it harder to make their shells because of the water’s increased acidity. The oceans do absorb some of the CO₂ that would otherwise increase temperatures faster. However, an important question is whether the oceans can continue to absorb this much CO₂.

Carbon dioxide levels have been increasing since the early nineteenth century. Coal was burned to power factories, trains, and ships. New engines were developed that relied on oil and gas. More people required electricity, which was usually generated from the burning of coal. More resources, more production, and more fuel were needed as the global population increased.

By the mid-twentieth century, the effects of fossil fuel use became very clear. In parts of Pennsylvania and London, toxic air pollution was causing deaths in 1948 and 1952. In the 1960s, scientists and governments began to call for environmental legislation, which helped reduce pollution. For example, between 1960 and 2010, Los Angeles greatly reduced the amount of smog in its air.

There is still much more work to do. Climate scientists warn that if we do not act quickly to reduce emissions, both the Earth and humanity may be doomed.

So now what?

Humanity must cooperate to lower CO₂ levels and curb plastic use. Renewable energy resources like solar, wind, and water power can be used in place of fossil fuels. But what can we do as individuals to help our community and our planet?²

Environmental activist Jane Goodall says we must think about the environmental impact of our actions. “Everyday you make some impact. So start thinking about the consequences of the little choices you make,” she said. “What do you buy? Where did it come from? Did it harm the environment?” If the majority of Earth’s 8 billion population took the time to think about these choices on a daily basis, we could dramatically change the way we interact with the environment.

1 As of September 4, 2024, the world population according to the US Department of Commerce, Census Bureau was 8 billion. A visit to https://www.census.gov/popclock/ will tell you the current estimate.
2 To explore ways that you can help combat climate change, check out the articles, videos, and activities in Climate Project.