Our world governments need to start taking their own advice; the effects of human intervention

BY SIMONE J. SMITH

Human intervention has been destructive to our environment in various ways, often unintentionally, due to a lack of understanding, foresight, or responsible behavior. Due to this, human intervention has had a significant impact on the environment over the years. These impacts are often referred to as anthropogenic, or human-induced environmental changes. History is peppered with times when our patchy knowledge of natural systems has led to questionable interventions with unintended — and sometimes disastrous — consequences.

This article is a reminder that even those with great intentions can still inflict severe damage. Let’s flip through the pages of history and see exactly how humans have messed up our world.

Indestructible starfish

The Indo-Pacific is home to threatened coral reef ecosystems, and one of their natural predators can decimate entire reefs in a matter of months. Crown-of-thorns starfish (Acanthaster planci) can reach 31 inches (80 centimeters) in diameter and sport up to 21 arms covered in hundreds of toxic thorns. They satisfy their voracious appetite by inverting their stomach, so it hangs out of their mouth, and sucking the tissue off coral skeletons.

In some places, people attempted to kill the starfish by chopping them into pieces — forgetting that starfish can regenerate body parts, and so inadvertently multiplied their numbers. People also injected the animals with poisonous chemicals and accidentally caused them to spawn, releasing thousands of sperm and eggs into the water. A more efficient method is to remove the starfish from the reef, according to Oceana.

Cane toad bonanza

Toward the end of the 19th century, Australia’s budding sugarcane industry encountered a bump in the road. Native beetles had acquired a taste for the crops that were introduced a century earlier and were causing huge losses by chomping on the roots.

Entomologists heard about the American toad’s (Rhinella marina, formerly Bufo marinus) apparent success in curbing cane beetle populations in Puerto Rico. In 1935, after importing a breeding population from Hawaii, scientists let 2,400 toads loose in the Gordonvale area of Queensland, but they failed to check whether the toads actually eat cane beetles and, according to the National Museum of Australia, did not assess the potential environmental impacts.

Cane beetle populations held steady, and the bugs continued to ravage sugarcane plantations. Meanwhile, the cane toad population exploded, and the amphibians spread from Queensland to coastal New South Wales, the Northern Territory and parts of northwestern Australia. Cane toads secrete venom that can kill animals that eat them, which soon triggered declines in native predators — including northern quolls (Dasyurus hallucatus), now listed as endangered.

The invasive toads still wreak havoc today, but “There is unlikely to ever be a broadscale method available to control cane toads across Australia,” the Australian government said on its website.

Underground inferno

In May 1962, a fire started in the small borough of Centralia, Pennsylvania, which reportedly originated as an intentional burning of residential trash in an abandoned mine. As the flames spread, people tried to douse them with water several times over the next few days, but no amount of effort seemed to extinguish the fire. The waste continued burning into August, when the council alerted local coal companies and state mine inspectors of the possibility of a mine fire.

Centralia sits atop a labyrinth of abandoned coal mines, which may have been set ablaze by an unsealed opening in the trash pit. The fires are still burning today. Federal and state governments gave up fighting the flames in the 1980s, opting to relocate inhabitants instead. The smoldering coal seams have baked the town through the ground, bleaching trees white and opening fissures that leak poisonous gasses.

Little remains of Centralia except a deserted grid of streets and a dozen people who refused to leave. It could be another 250 years before the coal fueling the underground inferno runs out.

Electrocuting fish

Asian carp were imported to the U.S. in the 1970s to deal with algal blooms in water treatment plants and aquaculture ponds, but they soon escaped confinement and made their way into rivers and streams — some species can even jump over low dams and overcome barriers in waterways. Having escaped, they became invasive and interfered with fishing activities.

Carp have spread to the Mississippi River and its tributaries and are on the verge of spilling into the Great Lakes, where they could wreak ecological havoc and tank the annual $7 billion fishing industry. As a preventive measure, the U.S. Army Corps of Engineers erected an underwater electric barrier in Chicago’s waterway system in 2013. The design stuns fish as they swim upstream, and their limp bodies drift back down. While it seems to have kept carp at bay so far, the barrier may not be completely reliable and could let small fish sneak through.

Flushed away

For 7,000 years, the Mississippi River has carried sediment from across North America and deposited it in the Gulf of Mexico. There, the mud piled up into lobes of land separated by swampy water channels, shaping the famous river delta and its marshes. But in 1718, French colonists who founded New Orleans on a finger of land alongside the Mississippi’s main channel were dismayed when spring floods sent water streaming through the half-finished buildings. They ordered the construction of a levee — a mound of earth acting as a barrier to keep the city dry. Over the decades, more and more levees were erected until they merged into a wall stretching thousands of miles north into Missouri.

These constructions enabled cities and farmland to flourish, but they also funneled the river into a single torrent. While the Mississippi formerly recycled the soils it flushed away by creating marshland, it now shoots straight out into the gulf and dumps them in the deep sea. As a result, since the 1930s, Louisiana has lost over 2,000 square miles (5,200 square kilometers) of land to the ocean — an area equivalent to a football field drowning every 100 minutes.

The loss of protective wetlands worsens the impact of storms and hurricanes on coastal communities. Compounded by rising sea levels, land loss also threatens Louisiana’s commercial fishing industry — which makes up 30% of the U.S. yearly catch — five major ports and rich wetland ecosystems.

Our world governments continue to speak about climate change and the way we as citizens need to act in order to save this planet; maybe they need to start taking their own advice.