The Holocene Civilization was born during the Holocene, an epoch that lasted about 10,000 years. During this time, the average global temperature was incredibly stable, never varying more than 1°C. As a result, weather patterns were also very stable, creating conditions that were perfect for societies to flourish.

Climate Change

The most obvious sign that the Holocene has ended is climate change. Throughout the Holocene, the concentration of carbon dioxide (CO2) in the atmosphere was below 300 parts per million. Now it's well above 400 parts per million and rising fast. CO2 levels have spiked at various times throughout Earth's history, but it's usually from volcanoes. The result is widespread biodiversity loss because many species are unable to adapt to spiking temperatures. Currently, CO2 is being emitted 200 times faster than past extinction events. That means temperatures are going to rise faster than they have in millions of years, setting us up for what could become the worst mass extinction event in Earth's history.

Later this century, the heat will make huge swaths of the planet uninhabitable for humans. When that happens, people will be forced to move closer to the poles, but those places will experience extreme heat waves as well, which will cause the permafrost to thaw faster, releasing more greenhouse gases and making the planet even hotter.

Pollution

Another sign that the Holocene has ended is the accumulation of synthetic chemicals in the environment, especially in the air we breathe. Air pollution from fossil fuels changes the brain, makes bones more brittle, and increases the risk of Parkinson's disease. Already, air pollution kills about 7 million people every year, and the number keeps rising. Another type of pollution that has gotten increasingly worse in recent years is chemical pollution- specifically, PFAS (per- and polyfluoroalkyl substances), also known as "forever chemicals." These synthetic chemical compounds are used in thousands of everyday products and inevitably make their way into the soil, plants, water, and air. Even tiny amounts of forever chemicals pose health risks and disrupt key biological processes, contributing to all sorts of diseases in both humans and animals. Huge amounts of forever chemicals can be found in wildlife all over the world. It's so bad that eating one wild fish is the equivalent of drinking tainted water for a month.

Biodiversity

Speaking of the sixth mass extinction, it is well underway and rapidly getting worse thanks to climate change, pollution, and habitat loss. Humans have already killed 83% of wildlife and 1/2 of plants, and they've wiped out 71 branches of species from the tree of life. A couple centuries ago, humans made up a small percentage of animal life, but today, humans and their livestock make up 96% of animal biomass. Since 1970, global wildlife populations have fallen by 69%, with species going extinct 1000 times faster than they were before humans came along. It's already so bad that it will take the Earth at least 10 million years to recover. In the meantime, food webs that we rely on for survival are in danger of collapsing.

Animals of all types are in decline: mammals, reptiles, amphibians, and especially birds. Since 1500, at least 182 species of birds have gone extinct, and today, half of the world's bird species are in decline. Some of it is from extreme heat, some of it is from plastic pollution, and the rest is from other human activities. So far, 1/3 of North America's birds have vanished, and 2/3 of bird species are facing extinction. Even more alarming is what's happening to insects. In the past 50 years, insect numbers have declined by 75%. Currently, insect populations are declining exponentially at a rate of about 2.5% per year. Although insects...