Anthropocene - The Age of Human Impact

Why are species brought to an area on purpose?

Species are brought to an area to help reduce or manage animals that would cause the problems.

They are also brought in as pets or for decoration.

Why do people and businesses that import species don’t expect the consequences?

This is because they can’t predict how the species will behave in a new environment; nor scientists.

What happens when species are introduced in a new environment? Give an example.

Introduced species usually multiply too quickly and become invasive.

"invasive" means something that spreads in an aggressive, uncontrollable, and often harmful way.

For example, when five cats were introduced in Marion Island (a part of South Africa) as pest control for mice, after some years there were 3,400 cats living on that island and also consumed the local bird population, endangering it.

"Endangered" means a species is in a danger of becoming extinct, or disappearing forever.

What are the 3 main impacts of humans when introducing invasive species? (slide 10)

• On ecosystems

• Humans also impact the transformation of the Earth’s surface

• The world’s climate

What is the Anthropocene?

Anthropocene is a term that helps describe our current geological epoch (period of time), relative to previous periods such as the Pliocene or Miocene.

Why was the Anthropocene word created?

The Anthropocene word was created because human activities have had a significant global impact, as well as a radical geological and ecological change; so a new term of the epoch needed to be made.

What does the word Anthropocene come from?

Anthropo - human

cene - new

However, its definition is controversial because Crutzen thinks that it started in 1784 when James Watt improved the steam engine, while others think that it started much earlier with the beginning of agriculture.

How old is the Earth? Explain the image.

What are stratigraphers and what did some of them argue?

Stratigraphers are scientists who study rock and soil layers.

Some argued that future geologists will acknowledge a clear change in today's layers, which supports the idea of the Anthropocene.

What do we ask ourselves in an Anthropocene epoch?

Instead of determining what impact the Earth has had on humanity, we ask ourselves what impact humanity has had on Earth.

We also think whether we will create a world in which we ourselves can no longer live.

What are the three different big titles that fall in these epochs?

• Pre-cambrian

• Paleozoic

• Mesozoic

• Cenozoic

What do the titles such as the Anthropocene epoch in the soil show us? Give an example.

They help show us major things that happened on Earth and their periods, including human impacts that may mark the start of the Anthropocene.

For example, scientists can find plastic pieces or chemical pollution in the soil that only appeared because of human activity.

Who rejected the Anthropocene proposal?

• International commission on stratigraphy (ICS)

• International Union of Geological Sciences (IUGS)

Who will use the term Anthropocene?

• Earth and environmental scientists

• Social scientists

• Politicians

• Economists

• Public at large

What does unidirectional change mean? Give an example.

Unidirectional change means a change that cannot change its direction and can’t go back to the way it was before.

For example, stopping the burning in Eastern Cape grasslands doesn’t make the land return to its original species mix.

Give me a concrete example of unidirectional change.

It’s when early bacteria, also known as photosynthetic bacteria (more precisely cyanobacteria as its a type of photosynthesis bacteria) added oxygen in the atmosphere as it is its waste product. It used light, water and CO2 to produce energy.

As oxygen built up in the atmosphere, many older anaerobic bacteria that couldn’t live with oxygen died out.

Because the air couldn’t go back, this is an example of unidirectional change.

State the two impacts humans had on the planet during the Anthropocene epoch

1. During the Industrial Revolution, human activities released large amount of gases such as carbon dioxide and methane, which traps heat around the Earth.

This warming of the planet is called the enhanced greenhouse effect and can cause problems like climate change.

2. Humans have also impacted the environment by changing the land cover, such as cutting down forests and expanding farmland.

Land cover - the way the land is used or what is on it such as forests, farms or cities.

Interpret the graph about the global land use for food production

What should be done to improve our land use in the first chart of the slides?

We should eat more plant-based foods as plants give us most of our calories and protein while using less land than meat and dairy.

Interpret this chart about “How is the world's land used?”

Do we need more land for cities?

No not really because we already use very little land and can build smarter.

However, what matters more is using land wisely, protecting nature and reducing how much land is used for livestock and farming so the environment stays healthy.

Interpret this graph

What is the difference between deforestation and land-use change?

Deforestation is when individuals remove forests in order to make space for agriculture, roads, farming and etc. On the other hand, land-use change is when humans change the way a land is used for a specific purpose.

What are the irreversible impacts of deforestation and land-use change?

• Deforestation can cause permanent loss of forests and the species that depend on them.

• Land-use change can damage soil and ecosystems in ways that cannot return to their original condition.

Irreversible impact - It means changes that cannot be undone or returned to the way they were before.

What is the oxygen catastrophe?

The oxygen catastrophe happened about 2.4 billion years ago when cyanobacteria began using photosynthesis and released large amounts of oxygen into the atmosphere.

This new oxygen killed many anaerobic bacteria and other anaerobic species, which could not survive in oxygen.

Why is the Oxygen catastrophe a lesson to humans about the consequences to our actions?

This is a lesson to humans about the consequences of our actions as it shows how biological activity can alter the Earth which can lead to catastrophic consequences due to our actions.

Why were animals and plants domesticated?

• Animals were domesticated to help with work, provide food, and offer protection.

• Plants were domesticated so people could grow reliable food instead of only gathering wild plants.

What have human changed during the Anthropocene epoch?

1) the climate

2) the landscape

3) the diversity of life on Earth