Source: Earth PD http://bit.ly/1ESoBKp Earth Clipart PD http://bit.ly/1ESoBKp Food Web CC http://bit.ly/1MFN5ZI Atmosphere PD http://bit.ly/1FJ8GkJ
Hi, I'm Jensen Morgan. We're going to talk about some great concepts in environmental science. Today's topic is Earth systems. So let's get started.
We're going to talk about Earth systems and the importance of keeping those systems in balance. Our Earth is the composition of many different systems working together to create our biosphere and planet. These systems have an impact on humans, and humans have an impact on them. Because of this, it is important for us to understand these systems as well as a relationship with each other.
Some important earth systems are as follows. Atmospheric, which includes the weather and climate. Geologic cycles, which includes the carbon, water, and nitrogen cycles. Energy production and cycling, which includes the vital process to all life-- photosynthesis. And the movement of energy through ecosystems, including food webs and food chains. Without these systems, healthy and balanced, ecosystems cannot thrive, which inevitably results in negative impacts to human quality of life.
As I said before, life on earth depends upon a specific balance in synergy between these Earth systems. If one system or piece is affected, it will inevitably impact the whole over time, possibly creating significant challenges to life. Life on Earth is dependent on a specific balance between four major systems. First-- temperature-- current life on Earth has adapted to a particular range of temperatures, including humans. And if that range were to substantially shift, mass extinction could occur.
Atmospheric composition-- our atmosphere has reached a concentration of 21% oxygen over millions of years. This composition is essential to human life. If it were to increase or decrease, humans could go extinct. In addition, as carbon dioxide increases, global temperatures rise, which could impact life on earth. Without our atmosphere entirely, most life on Earth would not be able to survive or be protected from falling asteroids, which burn up in our atmosphere currently.
Ozone-- our ozone layer protects the planet from receiving too much UV radiation that could cause severe genetic mutations, cancer, and death in all species. Our ozone layer also regulates Earth's temperature. Without it, our planet would heat up. Water-- life on earth would not exist at all without water. And if the 3% of fresh water on our planet disappeared, many species would struggle to survive or go extinct.
I'm going to give you an example of what might happen if the balance in just one of these Earth systems were tipped. Let's say that the concentration of ozone in our atmosphere was lowered significantly, perhaps by human air pollutants, such as aerosols, or just by natural causes. As the ozone layer thinned, UV radiation reaching the Earth's surface would increase. This would lead to genetic mutation, increased cancer levels, and even deaths to many species, including humans.
In addition, the increased radiation reaching the earth would tip the balance in Earth's temperature, causing it to heat up. Increased temperatures on Earth would make it harder for other species to survive who have adapted to colder temperature ranges. Then as the average global temperature rose, other chain reactions would occur. Ice caps and glaciers would melt faster, reducing the availability of fresh water.
Ocean temperatures would heat up and release more CO2 into the atmosphere because oceans are carbon sinks. Which would then lead to further rises in average global temperature. This process would continue setting off more and more chain reactions. This is why keeping the balance in our systems is so important.
Now let's have a recap. We talked about Earth systems and the importance of keeping them in balance for life on Earth. Well, that's all for this tutorial. I hope these concepts have been helpful, and I look forward to next time. Bye.