Imagine laying in bed with the lamplight on the bedside table turned on, reading to your son or daughter who is just learning the alphabet. You pull out the old picture book that your mother used to read to you when you were little and start to point to the pictures on the page, saying each word out loud. As you flip to the next page, your finger rests on the image of an elephant, but the word catches in your throat. Your child asks, "what is that animal, mommy?". You reply, "well honey, that animal was called an elephant. But they don't live on Earth anymore".

Soon, this imagined scenario will become reality. Normally, the natural background extinction rate for animals is one to five species per year. Now, scientists are estimating that Earth is losing up to 1,000 times the background rate, which is dozens of species going extinct every day.

Why is it happening? What is the cause? The cause is not a what, but a who: us, humans.

Currently, we are in the midst of the 6th mass extinction and it is all due to human activity. The rising global temperature due to increased greenhouse gas emissions by humans has caused the temperatures of climates and entire ecosystems around the world to fluctuate. Even the smallest increase in the temperature of say, a river flowing through a forest, could detrimentally affect the organisms inhabiting those biomes. Many species on Earth rely on the ecosystems they live in to provide perfect conditions for their survival. One small change in temperature could cause a cascade through the food chain, and make it very hard for species, who depend of the lives of other organisms for food and energy, to live.

In addition to warming the planet, humans are growing at an overwhelming rate. And with more people, there needs to be more food. Currently, 11% of Earth's land is being used for agriculture, and of that 11%, 32% is for livestock and rangeland. That might not seem like a lot, but that is about the entire continent of South America and about half of North America, which is a large chunk of land. Many places that are perfect for cropland and contain nutrient-rich soil are currently covered with forests and flourishing ecosystems. But does that stop humans? No. For example, deforestation in the Brazilian Amazon rainforest rose more than 88% in June 2019 compared with the same month in 2018. Destroying these ecosystems is displacing and killing many of the organisms that rely on that biome for survival. Many are being forced into human-active areas, where they do not have the resources to survive and are being poached and killed off in road accidents.

Just recently, the Javan Tiger native to the Indonesian Island of Java went extinct due to the loss of habitat and agricultural development within its ecosystem. And similarly, the Dutch Alcon Blue Butterfly found in the Netherlands has also gone extinct from the loss of its main food source. This was due to an increase in human farming and clearing of its ecosystem for buildings.

Almost all of the species gone extinct in the past 50 years are because of human activity. As we keep killing off so many species, the resources that they provide to us will be in short supply. Without every well-oiled part of a machine, the machine will eventually burn out and stop working. In order to have a sustainable way of life, and to continue to grow as a society and as the human species, we need each part of our machine. And without all of the organisms on Earth to keep it running, we will eventually die out too.

The normality of teaching your children about the animals that live on Earth might seem like just another ordinary part of life, but in the future, instead of visiting the zoo, you will be walking the halls of a museum filled with stuffed replicas of the animals that once proudly roamed the Earth.