The Greenhouse Effect
Understanding this Natural Contributor to Climate Change
The greenhouse effect is to blame for climate change on Earth. This is well-established among the scientific community, even those who would say that humans have played no role in creating it. Therefore, to understand they why's of climate change, it's important to know at least a bit about the greenhouse effect and why you hear people talking about things like cutting emissions and CO2.
What is the Greenhouse Effect?
Most people are familiar with greenhouses, built with glass walls and ceiling and used to grow plants. The glass allows sunlight through without exposing plants to cold temperatures. Because the sun's radiation makes it through, it can be absorbed by items inside the greenhouse and ultimately traps heat. This makes it warmer in the greenhouse, and allows the plants to thrive.
On our planet, Carbon Dioxide is an abundant greenhouse gas. It makes our planet a nice place to live in the correct amounts. In fact, it's largely responsible for our planet being warm enough in the first place. Too little CO2 and you get a cold planet, as with the past ice ages. Too much, and the planet grows warmer. The planet Venus has an atmosphere comprised of 95% CO2. Despite being the 2nd closest to the sun, and fairly close to our planet, Venus is the hottest planet in the Solar System. This is due to its atmosphere producing a greenhouse effect. The planet's surface absorbs much, much more heat than that of the closest planet - Mercury. Climate change would not make our planet as hot as Venus, but negative impacts begin to occur with just an increase of a few degrees Celsius.
What are Greenhouse Gases?
A greenhouse gas is something similar to the glass in the greenhouse, which is where the gases get their name. These gases allow the sunlight to pass through but won't let the heat (radiation) escape. Greenhouse gases include but are not limited to:
- Carbon Dioxide (C02) - A byproduct of burning fossil fuels including coal, oil, and methane (natural gas). Most emissions are likely from power plants and industries.
- Methane - primarily emitted from agriculture - mainly livestock.
- CFCs (Chlorofluorocarbons) - you see this on the back of hair spray and air freshener. CFC-free. It's a potent greenhouse gas that would have depleted the ozone layer, which is now in recovery. While these contribute to warming, their main risk was removing the ozone layer and creating a much greater risk of skin cancer.
- Nitrous Oxide - much more potent than CO2 but thankfully not emitted in anywhere near the same quantity.
- Water Vapor - See below.
If greenhouse gases were at a low concentration in the atmosphere, we'd have an ice age. Simply because the glass is off the greenhouse roof and heat can radiate back into space. With none of these, earth would be cold and uninhabitable.
When in higher concentrations however, you get global warming. This is the greenhouse effect that we are experiencing now (discovered by Svante Arrhenius in 1896 to explain ice ages). It is now more often referred to as climate change. Global warming sounds kind of neat if you live in Alaska (and indeed seemed great to one of the scientists who discovered this, living in a cold country in 1890s). Climate change is far more threatening with the realization we are speaking on a global scale and not just being warmer.
The climate change term is also a more accurate depiction of the changes the planet is experiencing. This isn't just a conspiracy theory, it's happening now. The only argument remaining that has any basis in reality is if humans caused it directly.
The Uncontrollable Greenhouse Gas: Water Vapor
As the planet warms, one of the most abundant greenhouse gases is released into the air: water in vapor form. With more heat the process of evaporation creates water in the atmosphere. More gases in the atmosphere, causing the greenhouse effect, causes more water vapor which causes more warming. This is a cycle that is causing the effects of our CO2 and Methane emissions to be more problematic.
