Earth's Breaking Points: Causes of Mass Extinction

If carbon dioxide levels rise significantly, then more heat is trapped in the atmosphere. If the global temperature increases beyond what species can handle, then it becomes one of the major causes of mass extinction.

If a volcano erupts on a massive scale, then it releases particles that block sunlight. If sunlight is blocked, then the global temperature drops, causing a rapid climate shift.

If a large asteroid hits the Earth, then it kicks up millions of tons of dust. If that dust prevents photosynthesis by blocking sunlight, then the entire food chain collapses.

If the atmosphere has high levels of carbon dioxide, then the ocean will absorb a large portion of it. If this creates a chemical reaction that lowers the pH of the water, then the ocean becomes acidic and kills coral reefs.

If a change takes millions of years, then natural selection has time to favor new traits. If the change happens in only a few hundred years, then species cannot evolve fast enough and will likely go extinct.

If continents move toward the poles or the equator, then the local climate for those landmasses changes. If the climate changes drastically, then species living on those continents may lose their habitats.

If white ice reflects heat but dark water absorbs it, then melting ice makes the planet hotter. If the planet gets hotter, then more ice melts, creating a loop that accelerates mass extinction.

If long-term eruptions occur, then they act like a giant chimney for greenhouse gases. If carbon dioxide builds up, then it triggers the global warming associated with mass extinctions.

If water is turned into ice on land, then the global sea level must drop. If the sea level drops, then the shallow seas where most life lived at the time disappear, leading to mass extinction.

If the temperature of the ocean rises, then its capacity to hold oxygen decreases. If the oxygen levels drop too low for fish to breathe, then a mass extinction occurs in the water.

If trees are removed to make room for crops, then the animals that lived in those trees lose their homes. If they have nowhere else to go, then their population will go extinct.

If a species is to survive, it must fit its environment. If the environment changes in a short period due to climate or habitat loss, then the species will fail to adapt and will eventually die out.

If the fossil record shows extinctions taking thousands of years, then they are usually the result of long-term environmental changes. If climate shifts and habitat loss happen over generations, then the process is not a single-day event.

If the oceans warmed up, then frozen methane on the sea floor melted and turned into gas. If methane is a powerful greenhouse gas, then its release caused the temperature to skyrocket even further.

If an event is powerful enough to change the global environment quickly, then it can lead to species loss. If cooling, acidification, volcanoes, and plate movements occur, then they are valid triggers; however, a normal rainstorm is too small.

If humans cut down forests or build cities, then the physical space available for wildlife shrinks. If these changes happen too fast for animals to move, then they are leading causes of extinction.

If an event happens without human intervention, it is a natural cause. If asteroids, volcanoes, and sun cycles change the climate, they are natural; plastic and hunting are human-driven.

If sea levels drop due to an ice age, then the shallow areas near coasts dry up. If these areas vanish, then the organisms living there lose their habitats and die.

If the oceans stop circulating correctly due to temperature changes, then the water loses its dissolved oxygen. If the oxygen levels hit zero, then the condition is called anoxia.

If the Earth cools, then water freezes into ice caps and sea levels fall. If sea levels fall and the water gets cold, then tropical reefs and plants that need warmth will die out.