Macrocosm: Biodiversity Loss, a Human Issue

Manfred Bortoli

“Bluefin tuna populations have decreased dramatically since the 1950s. As the world struggles to save the species, these fishermen depend on them to make their living… one Bluefin at a time.” 

This statement periodically appears on screen during every episode of the National Geographic television series Wicked Tuna. For the next hour, viewers watch as commercial fishermen hunt, kill, and sell this majestic creature in a bid to earn the most profit and “top the fleet”. As of 2011, the International Union for Conservation of Nature has classified the Atlantic Bluefin tuna as endangered on its Red List of Threatened Species. Wicked Tuna premiered in 2012. 

The main reason for this classification is overfishing. So it is ironic that an organization which touts itself as using “the power of science, exploration, education, and storytelling to illuminate and protect the wonder of our world”, would actively contribute to the extinction of any species. Stooping so low as to play on viewer sympathy with phrases such as “these fishermen depend on them to make their living” to excuse its glorification of commercial Bluefin fishing. I wouldn’t worry too much about this considering National Geographic pays its stars well with some of its longstanding cast members rumored to make up to $100,000 per episode.

Wicked Tuna has proven so popular it even received a spinoff series – Wicked Tuna: Outer Banks. So, as the Atlantic Bluefin Tuna fights to survive, National Geographic fights for ratings and broadcasting revenue.  

Historically, there have been only 5 mass extinction events in the lifetime of our planet. The most recent, the End-Cretaceous, transpired 65.5 million years ago. Since the 1990s, scientists have warned that we may be on the verge of another. Now, a recent United Nations (UN) report has revealed that around 1 million plant and animal species are at risk of extinction. Mass extinction events occur when the current rate of extinction greatly exceeds the natural background rate of extinction. Current extinction rates are a startling 1,000 times greater than the background extinction rate. A single extinction can devastate an entire ecosystem; many extinctions will destroy Earth’s precious biodiversity.

More Than Just Temperature

To put its findings into context, the UN report identifies the five leading threats to Earth’s natural ecology. It names changes in land and sea use as having the largest global impact followed by direct exploitation of organisms, climate change, pollution, and invasive alien species. Environmental degradation and global warming affect more than just temperature. The sea level is rising, oceans are acidifying, and we are experiencing more persistent and extreme hurricanes.

Pollution and land use changes (e.g. deforestation) add tons of carbon dioxide, a greenhouse gas, to the atmosphere of which the ocean absorbs a whopping 30%. When carbon dioxide reacts with water it forms carbonic acid and lowers the pH of the ocean. This is very problematic for organisms with calcium carbonate skeletons or shells because their cells can dissolve at acidic pH. Adding further fuel to the flame, aquatic species must also contend with heating oceans – the main basis for harsher hurricanes. Warm water is more likely to evaporate into the atmosphere, so when a storm comes along there is much more water vapor sitting in the clouds ready for it to dump. Water expands when it is heated, causing the sea levels to rise. As a result, storm surges gain strength because there is more water behind them. Warm ocean waters have more energy and power which is available to storms, enabling them to escalate faster.

Only the Strong Survive, Or Do They?

Many attribute the alarming surge of endangered species to natural selection, asserting “it’s just ‘survival of the fittest’”. They argue that species must emigrate or adjust to the changes in nature caused by human activities, or else they will face the consequence of extinction. This is easier said than done, especially for the thousands of imperiled plant species. Consider this: if ivory poachers completely destroy the elephant population, is that natural selection? How about if whales are wiped out by commercial whalers? Here human behavior is directly shortening the apparent life span of entire species, much like it is doing with the 1 million from the UN report.

Silent Partner

Biodiversity loss affects every aspect of human life. A 2018 World Wildlife Fund report estimated that, globally, nature provides around $125 trillion worth of benefits to humans each year. The Amazon rain forest regulates air quality, taking in carbon dioxide and other pollutants from the atmosphere. These carbon stores are vital in mitigating the impact of global warming. Bees pollinate plants and trees cultivating a vast variety of flowers, fruits, and vegetables. Wetlands serve as ‘natural filters’ providing clean, safe drinking water to many communities. Beaches, gardens, parks boost tourism, a $2 trillion global industry. 40% of pharmaceuticals are derived from plants including the 20 best-selling drugs. 

Every species plays an important role in the natural ecosystem of its native habitat. Not only does each species occupy a unique niche, but it is also an irreplaceable part of an intricate food web. Food webs describe the movement of energy within an ecosystem between producers, consumers, decomposers, and the abiotic environment. They include everything from microscopic bacteria to massive elephants. When a predator is removed from an ecosystem, every level of the food chain is affected, this is called a trophic cascade. In the absence of a predator to limit population growth, prey species can reproduce unchecked. As they grow exponentially, the prey species will eventually deplete all of their available resources, including producer populations. Deprived of producers, consumers, and resources this ecosystem would eventually be devastated.

Light at the End of the Tunnel… Maybe

In order to halt biodiversity loss, we will need to make many radical, transformative changes and we will need to make them fast. This information isn’t new: scientists have echoed this warning for decades. There is, fortunately, a small glimmer of hope. The UN report includes many large-scale actions we can take in agriculture, marine systems, freshwater systems, and urban areas that would support sustainability. The exhaustive list includes: multifunctional landscape planning, implementing effective fishing quotas, creating marine protected areas, increasing water storage, increasing access to services for low-income communities, and legions of other suggestions. We just might want to keep the champagne on ice a little longer. These changes must be implemented by all governments, everywhere and some have proven more receptive to climate change responses and sustainability efforts than others. Biodiversity loss is not just an environmental problem. It threatens the security, economy, development, and health of all nations. While many have tried to turn this into a political issue, it is and always will be a human issue.