When human beings created civilization, they changed the Earth's environment in many ways. When humans began making cities, they had to cut down trees.  This is called deforestation and was one of the first environmental changes to occur. The growth of the Roman Empire, for example, caused forests to disappear in Europe and North Africa.  As a result, there was an increase in malaria, a disease spread by mosquitos.

Two events in the history of the world greatly changed the Earth's environment: the Columbian Exchange and the Industrial Revolution.

After Europeans came to the Americas in 1492, plants and animals were traded all across the earth. For example, corn and potatoes only grew in the Americas. But after Columbus, corn and potatoes spread all over the world. Also, horses, cattle and pigs were brought to the Americas from Europe. This changed the lives of the Native-Americans who lived there. This change was so great that we could never go back to the world they way it was before this time. It is called the "Columbian Exchange" because Columbus was the one who started it in 1492.

The Industrial Revolution started in Europe in the late 1700s. The Industrial Revolution changed the world by creating machines and factories. This caused many changes, including urbanization (the growth of cities) and pollution.  Urbanization caused cities to grow faster than at any other time. This is a process that continues to this day.

The Industrial Revolution grew on the the use of fossil fuels, especially coal and petroleum. As a result, the presence of carbon dioxide in the atmosphere has increased over the last 200 years. This has caused global climate change. Since 1880, the Earth's average temperature increased by about 1.4 degrees Fahrenheit.

Climate change can lead to more severe weather, the growth of deserts, rising sea levels and the spread of disease. Countries have attempted to deal with climate change by signing treaties, such as the Paris Climate Agreement and turning to more environmentally-friendly sources of energy, such as solar power.

Take a look at the following charts, highlighting some of the environmental problems facing the world today.