We Are Killing Ourselves Now – Human and Natural Threats to Life on Earth

Life on Earth will not last forever. Several major life extinction events have happened on Earth In The Past and will happen again. Here they are listed in the order in which they are occurring now and will likely occur in the future.

Human-Caused Climate Change
The growth of the human population has resulted in a massive impact on the Earth. Some scientists call our present period the Anthropocene because the Earth's climate is clearly more affected by human activity than anything else. Carbon dioxide, created from a variety of human activities, has increased faster, and is now one-third higher, than at any time in the past 400,000 years. Carbon dioxide, called a greenhouse gas, traps heat in the upper atmosphere instead of letting it escape into space. What is especially alarming is that the rate of climate change is exponential, not linear, meaning the rate of change is increasing. Things will be getting ever rapidly worse in the near future, all due to the activities of a large and still growing human population.

Higher Temperatures
High temperatures are setting new records almost daily throughout the world. This excessive heat is directly killing people who cannot get to cooler settings, such as those who are very young, elderly, or homeless. Night time temperatures remain high, so people and infrastructure cannot cool sufficiently before morning. If the electric grid overloads and goes down, greater numbers of heat related deaths can be expected. And the grid must be supplied by non-carbon energy sources such as solar or wind or it will only worsen the problem. Keeping the electric grid running during ever increasing demand will be a major challenge for governments around the world.

Heat is also causing problems with plants, not just people. Plants spend more energy growing their roots deeper to escape the heat, but use more nitrogen and phosphorous in the process. This results in less nitrogen and phosphorous available to develop fruit, which then becomes less tasty and nutritious. Many plants cannot produce fruit or seed at all because pollen becomes infertile at high temperatures. Increasing temperatures are causing more food crops to fail, leading to food shortages, higher food prices. malnutrition and starvation.

Warmer Oceans and Hurricanes
The increase in carbon dioxide has caused the oceans to warm steadily over the past 50 years. Warmer seas mean more water vapor in the air above the oceans. More humid air means hurricanes hold more water and move slower because of the weight of the extra water. When a hurricane reaches land today, it has more water to dump, moves slower, rains longer, and causes greater flooding. Flooding means more damage to homes, businesses and infrastructure, raising the cost of living in flooded locations, and causing more disruption to people's lives.

Methane
Human activities produce methane, which is 80 times more potent as a greenhouse gas than carbon dioxide in the upper atmosphere. The only good news is that methane breaks down into harmless gases in just 12 years in the upper atmosphere, compared to carbon dioxide, at 300 to 1000 years. Global warming in general is also causing the permafrost regions in northern climates to defrost, leading to the release of methane stored underground by bacteria decomposing dead plant material. At present, methane from all these sources causes one-third of total global warming.

Melting Ice and Rising Ocean Levels
Warmer oceans are melting sea ice in the Arctic and Antarctic. On land, warmer air temperatures are melting glaciers. This melting is causing sea levels to rise, gradually making coastlines uninhabitable when ocean storms sweep further inland, destroying buildings and homes. Some coastal cliffs are falling down, taking houses with them. Other coastal land is becoming permanently flooded.

Granted, many cities are sinking due to groundwater depletion, and this can make coastal seawater flooding worse. However, sea level rise by 2050 is expected to be more than one foot. The absolute sea level has risen at an average rate of 0.06 inches per year from 1880 to 2013. Since 1993, average sea level has risen at a rate of 0.12 to 0.14 inches per year – roughly twice as fast as the long-term trend. In some regions, entire coastal communities will have to be evacuated and rebuilt on safer ground. In certain places, that has already started.

Drought and Fire
Climate change affects each region of the world differently. Many dry land regions are experiencing less rain and more drought. Drought is causing crops to fail that would be used to feed animals and people.

Drought is also causing plants to become stressed and flammable. The result is forest fires that move faster, burn larger areas, and are harder to put out. The amount of acreage / hectares burned yearly has increased significantly in this past decade. A prime example is the Canadian forest fires, which have caused massive smoke pollution in northern U.S. states. Breathing the smoke from these fires, almost unavoidable, is leading to earlier deaths for people with underlying lung and heart conditions. Fire also destroys more wild animal habitat, leading to greater species extinction.

Pandemics
Increasing human population growth leads to town and city expansion and more contact with wild animals. Many communicable human diseases have come from animals, including Measles (cattle), Black Plague (Mongolian rodents), Flu (birds), AIDS (chimpanzees), Ebola (bats), Covid-19 (bats), and Mpox (African squirrels, giant-pouched rats, and dormice). The chance of a pandemic that will kill many people increases yearly. The Covid-19 virus, which caused over one million deaths in the U.S. alone, is just the latest in a series of diseases to come.

Micro Plastic Pollution
Humans have been producing, distributing, and consuming plastics in large quantities for generations. We now know that these plastics degrade on a microscopic level, shedding particles as fine as a small clump of molecules. These micro and nano sized particles have become so widespread they are everywhere, yet we cannot see them.

All oceans, lakes and rivers, all continents, glaciers, grasslands and mountains, are saturated with them. All food and drinking water, even the air we breath, are contaminated. It is estimated that the average person breaths in a credit card's worth of micro plastics into their lungs every week.

These plastic particles may have become a delayed poison. Medical doctors are now concerned that a rising tide of certain cancers, uncommon to people in their twenties and thirties, may be due to micro and nano plastics. Recent research has found these plastics to cause developmental problems in young animals and children. They also show up in brain tissue, and there is concern that the large amounts of microplastics in the brains of dementia patients may be contributing to that disease.

Chemical Pollution
Man-made chemicals called PFAS, which stands for per- and polyfluoroalkyl substances, are used to make grease-resistant food packaging, nonstick cookware, and waterproof clothing. These chemicals are nearly indestructible and are accumulating in the environment. They are toxic in even small amounts.

PFAS have now been linked to many health risks in humans and animals, including kidney and testicular cancer, liver and thyroid problems, reproductive difficulties, and abnormal fetal development. These chemicals have spread invisibly throughout the world and will be causing medical harm for generations.

Solar Flares Destroy Electrical Grid and Devices
A massive solar flare could knock out electrical systems in some parts of the world and destroy electrical devices if one happened with the right direction and intensity. Affected parts of society could suffer for months until all systems were restored. Solar flares have already caused noticeable damage to electrical facilities at some locations.

Future Asteroid Strikes
Asteroids will continue to hit the Earth, but the risk from large asteroids is low. Detection and prevention techniques have improved.

Earth Becomes Venus, Life Becomes Extinct
In one billion years, the slowly increasing heat of the sun will cause Earth to overheat and become like Venus. Liquid water will boil off as steam, air temperature will rise beyond broiling, air pressure will skyrocket, and Earth will become a barren planet devoid of all life. Humans must have found a way to leave Earth and move to a younger, benign star system before this happens, or humans, like the rest of life on Earth, will become extinct.

Galactic Collision: Andromeda and the Milky Way
In about 4.5 billion years, the Andromeda galaxy will collide with our Milky Way galaxy which includes our solar system and Earth. The exact time of this event is difficult to pin down. While its scale will be huge, there are not expected to be many collisions between stars because of the vast distances between them. Some solar systems will be moved around, a few stars will be ejected. Unless they have found a way to move to a younger star system, humans will not be around to witness this slow-moving spectacle.

The Sun Becomes a Red Giant
The sun will swell up to a red giant at the end of its life in five billion years and swallow Earth. Humans will not have to worry. The Earth will have been lifeless for four billion years.