World News | The sixth mass extinction is happening right now, and it doesn’t look good to us

Adelaide, October 26 (360info) Species are going extinct at an unusually high rate. Our efforts now will prevent the future from being too dire to imagine.

Evidence is mounting that the world has entered a sixth mass extinction. If the current rate of extinction continues, we could lose most species by 2200. The impact on human health and well-being is dire, but not inevitable.

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On a timeline of fossil evidence dating back to the very first signs of life on Earth—more than 3.5 billion years ago—almost 99 percent of all species that ever existed are now extinct. This means that as species evolve over time — a process known as “speciation” — they replace other extinct species.

Extinction and speciation do not happen at a uniform rate over time. Instead, they tend to appear as large pulses interspersed with long periods of relative stability. These extinction pulses are what scientists call mass extinction events.

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The Cambrian Explosion was an explosion of speciation about 540 million years ago. Since then, at least five mass extinction events (and possibly dozens of smaller ones) have been identified in the fossil record. Arguably the most notorious of them all was a massive asteroid that struck Earth in what is now the Gulf of Mexico some 66 million years ago. The collision immediately vaporized the species in the blast zone.

Species were later killed by climate change caused by powdery particles suspended in the atmosphere, and by intense volcanic activity caused by asteroids hitting the Earth’s crust. At the time, about 76% of species were extinct, of which the disappearance of the dinosaurs was best known. But the dinosaurs didn’t completely disappear — the survivors just evolved into birds.

To be classified as a mass extinction, at least 75 percent of Earth’s species must have gone extinct within a “short” geological period of less than 2.8 million years. This time frame seems long to us, since modern humans have only existed for about 200,000 years so far.

As a species, humans have participated in smaller extinction events that date back to the late Pleistocene (about 50,000 years ago) to the early Holocene (about 12,000 years ago), when most “megafauna” such as mammoths, Giant sloths, diprotodons, and cave bears have disappeared from nearly every continent for thousands of years.

Much later, around the 14th century, the expansion of European colonists around the world triggered a mass extinction, first on the islands and then spreading to the mainland as the drive to exploit natural resources accelerated. Over the past 500,000 years, more than 700 vertebrate and 600 plant species have gone extinct. These extinctions fell far short of the 75% threshold for including modern times in previous mass extinction events.

But these are only extinctions recorded by humans. In fact, many species go extinct before they are discovered—perhaps as many as 25 percent of extinct species never get noticed by humans. Even accounting for undiscovered extinction events, modern times still cannot be classified as mass extinction events.

But that’s not the total number of extinctions we should be concerned about; rather, it’s the extinction rate. If past mass extinctions took nearly 3 million years to occur, then we should examine how many species went extinct per unit of time relative to the “background” extinction rate that occurred between mass extinction events.

According to the fossil record, the average “lifespan” of a species is about one million years, which corresponds to a background rate of approximately 0.1-2.0 extinctions per million “species-years”. This puts the number of extinctions observed in modern times 10 to 10,000 times higher than the background rate. Even the most conservative estimates, ignoring undiscovered extinctions, place the modern era firmly within the expected range to qualify as a mass extinction.

An optimist might argue that the loss rate will definitely decrease over time, so we are unlikely to hit the 75% threshold. However, the outlook is not optimistic. The damage done so far means the rate of extinction will only accelerate.

Much of the damage to Earth’s life-support systems occurred in the last century. The global population has tripled since 1950, and about 1 million species are now threatened with extinction due to massive population declines, accounting for about 10 to 15 percent of all complex life on Earth. The total amount of vegetation on Earth has halved since agriculture began about 11,000 years ago.

Less than 15 percent of all wetlands recorded 300 years ago still exist today, and more than two-thirds of the world’s oceans have been damaged in some way by human activity. Not to mention climate change. Recent evidence suggests that global warming is causing ten times more extinctions than we would expect by looking at the temperature ceiling for just one species. In fact, when we take into account the relationships between species—such as predators that depend on prey, parasites that depend on hosts, and flowering plants that depend on pollinators—extinctions are expected to skyrocket in the near future.

The IUCN Red List tracks the most threatened species. But it also shows how little we know about extinction.

A truly indifferent person might also claim that as long as the species that provide resources for modern society survive, there is no reason to think extinction is a problem. Evidence suggests otherwise.

Species loss also erodes the services that biodiversity provides us. These include reduced carbon sequestration that exacerbates climate change, reduced pollination and increased soil degradation that damages our food production, deteriorating water and air quality, more frequent and severe floods and fires, and worsening human health. Even human diseases like HIV/AIDS, Ebola and COVID-19 are the result of our collective indifference to the integrity of natural ecosystems.

You might think that human societies and their leaders would prioritize damage control when overwhelming scientific evidence supports the need to change our course. In fact, the opposite is happening.

Short-term interests, economic systems that concentrate wealth in the few, the rise of right-wing populism with an anti-environmental agenda, and disinformation campaigns funded to protect short-term profits mean we are unlikely to be able to make changes on a sufficient scale to avoid environmental catastrophe. A dire future seems almost certain.

However, the grim outlook does not justify inaction. Conversely, if the global community embraces some fundamental but achievable changes, we have the potential to limit the damage.

We can scrap the goal of permanent economic growth and force companies to use established mechanisms such as carbon pricing to restore the environment. We can limit undue corporate influence over political decision-making and end corporate lobbying of politicians. Education and empowerment of women, including greater self-determination in family planning, will help stop environmental damage.

With a little effort and long-term planning, we can make our future less dire. (360info.org)

(This is an unedited and auto-generated story from the Syndicated News feed, the body of the content may not have been modified or edited by LatestLY staff)