Climate Change
So I thought that with COP26, the climate emergency and climate change being talked about so much recently, I would write a brief blog article explaining some of the science behind climate change. As much as we are told that change needs to happen and that greenhouse gas production needs to be reduced, we aren’t often told the science behind why it is necessary. So that is what I am hoping to do here.
So, firstly it is necessary to understand what the greenhouse effect is. This is a natural Earth phenomenon caused by our atmosphere, without which the average temperature on earth would be around -17 degrees. Essentially, Ultraviolet (UV) radiation emitted by our sun travels through space and reaches us here on Earth. Some of this radiation is reflected back into space due to the reflectivity of some of Earths surfaces, primarily cloud and ice cover (The reflectivity of Earth is called its albedo and is very important in negative feedback loops). The UV radiation that isn’t reflected back into space meets the Earth’s surface, is absorbed, and subsequently re-emitted as Infrared radiation which acts to heat the atmosphere. This radiation heats the atmosphere by being absorbed by greenhouse gases and radiated back down towards Earth, which keeps the heat in. Without this, the Earth would be a pretty chilly place to live. That seems pretty complicated, so I have drawn it in a very rudimentary diagram below:
The Greenhouse Effect
You might ask what are these gases that influence the Earth’s temperature? Well, the main ones are Water vapour, Carbon dioxide, Methane, Nitrous Oxide, with each having a higher heating potential than the last. Besides water vapour, carbon dioxide is the most abundant, and it persists the longest in our atmosphere, which is why it is the biggest contributor to the greenhouse effect. These gases have always been present in our atmosphere, have always acted to regulate our climate, and have always fluctuated through time.
Analysis of Ice cores has shown us that throughout the past 800,000 years, the temperature of our climate has directly coincided with the amount of carbon dioxide in our atmosphere, during ice ages there is less carbon, and during interglacial periods, there is more. A good representation of this is the graph seen below.
So where do humans come in? Well, In the past 250 years, since the Industrial revolution, human action has been the direct cause of unprecedented amounts of these gases being released into our atmosphere. Previously the highest amount of carbon dioxide ever recorded in our atmosphere over the last 800,00 years was around 300 parts per million (ppm), it is now at around 414 ppm. The majority of this additional carbon is thought to have been released in the last 25 years. The cause of the increase in greenhouse gas production is primarily the burning of fossil fuels for use in transport, electricity generation, industry, domestic properties and agriculture.
Side note: You can check the daily atmospheric carbon content on this website: Daily CO2
The additional carbon that we have released into our atmosphere has already led to a warming of the global average temperature of around 1.5 degrees, and if we continue with a “business as usual” approach, we are looking at possible global average temperature increases of around 5 degrees by the year 2100.
But climate change isn’t just about global temperatures increasing. The changes in our climate will differ depending on where we live; locally, nationally, and globally. While the majority of negative impacts will be experienced in the global south, here in Scotland we are not completely safe. Effects here might include sea level rise, worsening weather events such as flooding and droughts, depleted fish stocks and food shortages. I could write a whole new blog post on the doom and gloom of Climate change, but I will keep it fairly light for now. However, if you do have a morbid curiosity, feel free to check out this video:
RSA Minimate: Climate Change and the Future of Humanity | David Wallace-Wells - YouTube
The purpose of this blog post was to educate on the science behind climate change, not to preach about the importance of reducing your carbon footprint to save humanity (that might be the next one). But I will just say, it is important to do whatever we can to help combat climate change and to do it sooner rather than later, it isn’t too late to make a difference.
Thank you for reading and I hope you learnt something.
Jonny