The three principles, or pillars, of the sustainability of life on this planet are 1) solar energy 🌞 , 2) biodiversity 🐸 , and 3) nutrient cycling 🔄 . Each of these themes interacts with one another and earth's systems to sustain life.

Sustainability is one of those big ideas that can help you connect the various topics you learn throughout the course. In the Course and Exam Description, the have sustainability as Big Idea 4 which means it is important. Learn more through this blog on an Introduction into Sustainability and 🎥 video replay on an overview of sustainability!

When thinking about sustainability, think about the long haul. You are trying to manage your resources in a way that they last and are able to replenish.

Three Principles of Sustainability

1. Solar Energy 🌞

Solar energy is an important component of sustainability. It sustains our energy sources and natural resources.

Solar energy alone is something that we can rely for sustainability. Through solar energy, we are able to collect solar energy and turn it into electricity 💡 . Since solar energy is renewable and perpetual, it can be pivotal in making our energy sustainable 🌱 .

Direct sunlight being harvested by plants or by solar panels is not the only example of solar energy. Solar energy also helps in the production of other sources of renewable energy. For example, solar energy heats the atmosphere in a way that it creates wind. Thus, we have wind energy 💨 🔋 as a direct result of solar energy.

Solar energy also keeps environmental resources available to us. The sun plays a big role in many nutrient cycles 🔄 - which are another pillar of sustainability. In the water cycle, the sun causes evaporation. In the carbon cycle, the sun fuels photosynthesis. 

2. Biodiversity 🐢 🐿 🐍 🦌 🦆 

You might be wondering what biodiversity is and why it is important. Here are the answer to both. 

Biodiversity is the amount of species found in a certain area. The more species in an area, the higher the biodiversity. Biodiversity is important, because it is vital to a healthy environment. 

Each species will have different threats and vulnerabilities. If we had only one species of trees in a forest 🌲 , it could be easily destroyed by a single threat such as fire, pests, or disease. Different trees have different levels of susceptibility to different threats. Additionally, different species can protect an ecosystem against different threats. Many plants produce their own anti-fungal capabilities that can also protect neighboring species from a fungus. Biodiversity helps an environment last. 

Each species also provides a different service to the habitat. Take a coral reef for example. The coral provides a habitat for remora 🐟 . The remora help sharks by eating dead skin. Sharks 🦈 keep the fish population controlled. Different species work together to keep the ecosystem running smoothly. 

Humans can use resources from this flourishing habitat. The problem happens when people use the resources in an unsustainable way. If people take too much fish from the environment, the shark population will decline. When humans reduce the biodiversity of an ecosystem by over utilizing one species or resource, the consequences will create a vicious cycle that impacts many more parts of the ecosystem. 🔴 THIS IS WHY SUSTAINABILITY IS IMPORTANT! 🔴

Want to learn more? Watch this 🎥 video on Biodiversity and ecosystem services for more info!

3. Nutrient Cycling 🔄

Nutrient cycling replenishes some of earth's natural resources, such as carbon, water, nitrogen, and sulfur.  Nutrient cycling is all about the circulation of chemicals from the environment, through organisms (and man-made systems), & then back to the environment.

The water 💦 cycle replenishes our water supply through evaporation, condensation, precipitation, etc. However, when humans use water in an unsustainable manner, we can begin to ruin the resource. In many places on earth, humans use water faster than it can be replenished. This leads to saltwater intrusion and lack of clean water resources 🚱 .

Photosynthesis is another major example of nutrient cycling. Carbon Dioxide is cycled through plants and into Oxygen, which is released back into the air. Nitrogen fixation is another example of nutrient cycling that is crucial to sustainability of life.

It is important that we understand these nutrient cycles 🔄 , so we can understand how we need to change our resource use. We need to use resources in a way that they can continue to be replenished. This is the big idea behind sustainability. We want to manage our resources, so they can replenish instead of diminish.