Why Are Plants Green and What It Means for the Planet

A walk through a forest may send a person down a rabbit hole of questions. For instance, why are some plants poisonous, can trees feel pain, and why are plants green? Although there’s an answer for everything, the latter is good to know. 

Green plants are especially important for the environment and living beings. In addition to being a food source, plants produce oxygen, sequester carbon dioxide, enhance soil, and provide essential ingredients for medications. As climate change worsens and the planet undergoes significant adaptations, it’s crucial to understand how plants affect ecosystems. 

Why Are Plants Green: The Science Behind Plant Coloration

Answering the question, “Why are plants green?” is straightforward with a short biology lesson. Like all living things, there’s a scientific explanation for this natural phenomenon, and it starts with chlorophyll and photosynthesis. 

What Is Chlorophyll?

Plants have an organelle called chloroplasts, which is responsible for photosynthesis. The chloroplasts’ green pigment, called chlorophyll, helps capture sunlight energy, converting it into chemical energy to produce the plants’ food and oxygen.

However, green coloration is reflected off the leaf and isn’t absorbed, which is why the plant appears in different shades. Ultimately, chlorophyll sustains the plant’s life, making it a crucial part of a healthy planet. 

How Does Photosynthesis Work?

Photosynthesis is the actual process in which plants convert light energy into chemical energy for glucose. Plants’ green coloration indicates whether they successfully capture sunlight for energy. 

Although there are two types of photosynthesis — anoxygenic and oxygenic — plants, algae and cyanobacteria usually undergo oxygenic processes. During this activity, light energy moves electrons from water in plant roots to carbon dioxide (CO2), which generates carbohydrates. The CO2 receives electrons during reduction, while the water loses electrons and becomes oxidized. 

How Does Color Aid Plant Survival?

Plants undergo adaptations to survive in specific environments. In a tropical rainforest, plant leaves are large and dark green to gain as much light as possible under shaded tree canopies. In the desert, plants are usually a lighter green or gray to prevent too much sunlight from entering the leaves. 

The same scenario occurs between underwater and surface-level plants — aquatic leaves are much darker due to less sunlight exposure while floating plants are usually lighter. 

It is best to fill a garden with native plants to ensure they match the local climate and conditions. Doing so promises better growth and plant health, making it much easier to maintain long-term. Anything that isn’t native will require extra care, consideration and changes to their growing conditions to ensure it thrives. 

The Benefits of Plants on People and the Environment

The greener a plant, the more efficient it is in sequestering harmful CO2 and producing oxygen through photosynthesis. Plants are natural purifiers, uptaking pollutants and removing heavy metals and toxic nutrients through their root systems. 

They also prevent erosion and infiltrate soil with nutrients for optimal fertility. As a result, the planet has a more robust food supply to feed a growing and hungry population. Many plants are even a part of human and animal diets.

Among the most critical benefits is plants’ importance to the development of medicine. In 3500 BC, ancient Egyptians used plants to treat disease, documenting what they learned about plant-based treatments on temple walls and papyrus. In 2700 BC, the Chinese started using herbs as medicine, which has been carried out through numerous other cultures throughout the centuries.

By 1803, German pharmacist Frederich Serturner was the first person to isolate plant extracts for morphine. Over 200 years later, 40% of medicines in the Western world are derived from plants, including 20 bestselling prescriptions in the United States. 

Human Impacts on Plant Life

Introducing nonnative plants to ecosystems may happen intentionally or unintentionally in natural or unnatural ways. However, humans are the biggest driver of such nonnative plant integrations. Unfortunately, they may compete with and overrun native species, alter habitats, and increase the potential for wildfire in vulnerable areas. 

Scientists have focused their attention on plant extinctions to understand the ecological and societal impacts. According to Dr. Sandra Nogué from the University of Southampton in the United Kingdom, many studies have been conducted on islands where settlers arrived within the last 3,000 years, delivering insight into whether or not ecosystems have changed since then.

Studies suggest that humans have altered 75% of the Earth’s land area through various activities, from agriculture to construction and other industrial practices. For example, in the 1800s, Americans brought over hundreds of melaleuca trees from Australia to absorb water in the Everglades to expand farming — the devastating outcome still threatens the ecosystem today. 

Likewise, overharvesting of Chinese and Pacific yew trees threatens the availability of essential medicines. Yew bark is a critical ingredient in Paclitaxel, which effectively treats ovarian, lung and advanced breast cancers.

The green pigmentation in plants is not enough to save them from human activities either. A 2020 study found that 65 plants went extinct in the continental U.S. and Canada after European settlement occurred. Globally, 450,000 plant species are extant, which is 3.5 times higher than animal species. The study underscored the urgency of conservation efforts to prevent further extinctions.

In another study, scientists examined flowering plants’ potential for extinction. Using artificial intelligence tools, they discovered that 45% of 330,000 flowering plants are likely to be threatened. The impacts could have dire consequences for animals that feed on the flowers and the ability to develop new medications. By conserving them, they give the world options for undiscovered purposes. 

Green Plants Make the World Go Round

Few can comprehend natural processes. When one steps back to observe, the ability of plants to turn different shades of green is tremendous. As science has indicated, green plants are crucial for the world and the global population. Without this coloration, plants no longer demonstrate an ability to adapt and survive within the changing climate. Of course, humans are responsible for ensuring plant health for the world at large.