I have been meaning to write this post for a few weeks now. Renewable Energy and sustainability is something I am really interested in, and this post and this blog allow me to collate my thoughts and expand my knowledge in the field. This first post is primarily focused on the basics which I have compiled from my own experience and multiple other sources, but with subsequent posts, I plan to touch on other pressing issues and viewpoints. If you like what you see subscribe and become a follower to stay updated on any future posts and leave a comment saying what else you would like to see.
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Weather vs Climate
Let’s start with the basics. A common source of confusion when talking about climate change is the difference between weather and climate, and the ability to accurately predict these states. Weather describes the atmospheric condition over a short period of time. Climate, on the other hand, is the statistical average of the weather data over an extended period. The statistical average means we are able to predict climate better than weather. It is easy to say when summer or winter is, but it is difficult to forecast how cold, dry or cloudy any particular day will be. The data also tells us that that the average temperature has been slowly increasing year by year since the industrial revolution.
What is happening? Are there any ramifications?
The average temperature has been slowly creeping up over the years. This is happening due to an increased production of greenhouse gases, primarily Carbon Dioxide. Greenhouse gases form a blanket around the atmosphere in the lower troposphere and prevent heat from escaping. The more blankets we have, the hotter the average temperature will be. The research results are consistent with this theory. The lower troposphere is heating up, while higher up the stratosphere is cooling.
It has been generally agreed by the scientific community that an increase of 2 degrees Celsius would cause irreparable damages. Now you might be thinking, 2 degrees doesn’t seem all that bad, what the all the fuss about? Visualise a normal distribution. If the average temperature rises by 2 degrees it shifts the distribution to the right. Causing events which were once extremes to happen more frequently. The outliers are no longer outliers anymore. An example of this is the high number of mega-hurricanes that have been causing havoc in recent years. As the average sea level rises hurricanes become more dangerous.
There are also these things called feedback loops. The two most notable ones are:
a. As the Earth heats up it will cause ice to melt on both land and sea. Ice is generally very reflective and most of the solar irradiation bounce back to space. However, as the ice gives away to the land and the ocean, these entities will absorb more of the irradiation and heat up the temperature causing more ice to melt and create a feedback loop.
b. Water vapour is also a heat-trapping gas. If the planet heats up and the ice melts away the water vapour content in the atmosphere will rise, trapping more heat and creating another fast feedback loop.
Humankind tends to live close to the coast, look at Australia for example. Majority of the population live by the coast with the entire centre of the continent mostly uninhabitable. As the sea level rises, coastal areas will be swallowed up. This is especially true for countries like Bangladesh which are in deltas. The saltwater would slowly creep in and interfere with farming and agriculture. On the other end of the spectrum, droughts will occur more frequently and last longer. We will have to adapt to how we do agriculture and how we build infrastructure close to coastal areas. In general, people will be forced to moved further inland. With this comes its own bundle of economic issues, topics which are to be covered in a later post.
The Greenhouse Effect
Let’s talk about the Greenhouse Effect, a name that sounds pleasant but is anything but.
In a greenhouse, high energy high-frequency solar irradiation from the sun enters the glass house. The sunlight is absorbed by the plants and some of it is re-emitted in the form of low energy low-frequency infrared which is dispersed to the surrounding. The infrared waves do not have enough energy to exit the glass and are trapped. This, in essence, is the greenhouse effect.
The same phenomenon is happening on a much grander scale which is driving up the mean temperature and the reason behind global warming. Approximately 30% of the solar radiation is reflected by the Earth and the atmosphere, thanks to the clouds and the reflective ice sheets. 20% is absorbed by the atmosphere due to various aerosols and the remaining 50% is absorbed by the Earth. This is reemitted by the Earth in the form of low-frequency infrared. The frequency of a wave is inversely proportional to the amount of energy it contains. The low-frequency infrared therefore do not have sufficient energy to pierce through the atmosphere and is absorbed by certain types of gases called greenhouses gases and re-emitted in all direction.
The Gases and metrics
Let’s start with the main culprits and where they are used the most.
- Water vapour (H20) — The water cycle is a never-ending process, water is constantly being transferred between oceans, atmosphere, and land. Human activities affect the water cycle, but they do not directly change the concentration of water vapour level globally. Water as a gas traps heat but as droplets cool down the Earth surface. As the global temperature begins to rise, the ice sheets are melting and there is a higher content of water vapour in the air which is causing more heat retention. This is a prime example of a fast-feedback loop. For now, water vapour composition is mostly constant.
- Carbon dioxide (CO2) — Carbon Dioxide is the most discussed Greenhouse gas as humans have a direct impact on its concentration in the atmosphere. In the last two hundred years, atmospheric carbon dioxide has grown by almost 35%. The gas is mostly created during power generation using fossil fuel (coal, petroleum and natural gas).
- Methane (CH4) — Methane is the principal constituent of natural gas. When natural gas is burned, the methane oxides and forms carbon dioxide. Methane is also unintentionally pushed into the atmosphere during the extraction and transportation of natural gas. It is also produced by the decomposition of organic matter in the form of biogas.
- Nitrous oxide (N2O) -Nitrous Oxide is mostly produced by the agriculture industry as a byproduct of nitrogen fertilizers and animal wastes. It is also naturally produced by microbes in the soil.
- Ozone (O3) — Ozone is an interesting case. High up in the atmosphere, ozone forms a layer and helps shield the Earth from harmful UV rays. However, Ozone in the Troposphere is a nuisance as it absorbs the infrared radiation re-emitted by the Earth.
- Chlorofluorocarbons — CFCs were initially developed in the twentieth century as a safe alternative to ammonia. However, they have been slowly phased out due to their negative impact on the ozone layer. Currently, CFCs are used as coolants or propellants in refrigerators or aerosol sprays respectively.
The disproportionately drawn pie chart below illustrates the composition of the major greenhouse gases in the atmosphere. It excludes ozone as its contributions are minor and water vapour since humans do not have a direct impact on it.
The impact of a greenhouse gas depends on a number of factors:
1. Atmospheric concentration: Greenhouse gases only make up a small portion of the atmosphere but their impact is very significant. It is better to use a different unit of measure when talking about their concentration. 1 ppm stands for 1 part per million. Similarly, 1ppb is 1 part per billion and 1 ppt is 1 part per trillion. These are very small numbers and just by themselves do not make much sense. It’s only when we look at the relative values of concentration between the pre-industrial age and recent data that these values show how dire the situation is.
2. Lifetime: The average time the molecule resides in the atmosphere before being removed by a chemical reaction or deposition. The lifetime of gases is usually measured in years and may range from a few years to a couple of thousand.
3. Global Warming Potential: A measure of how much energy the emission of 1 ton of a gas will absorb over a given period of time relative to the emission of 1 ton of carbon dioxide. The larger the GWP value the more the given gas warms the earth over that time period.
Carbon dioxide stands out as it has the highest concentration amongst all of the greenhouse gases. It also has a significantly large lifetime ranging from 100 to 300 years. In comparison, methane and nitrous oxide have a higher global warming potential, but this isn’t realised due to their small concentration in the atmosphere. CFCs have the highest GWP, and their lifetime is variable since different CFCs have different deposition rates. A small concentration of CFC can therefore potentially make a huge impact. The global warming potential for ozone is hard to predict due to its short lifetime.
Another interesting metric to note is the composition of these gases compared to the pre-industrial age. Most gases have seen an increase between 40% to 70%, with CFCs not even being in the atmosphere before the 1750s.
The biggest blunder we can do is doing nothing. We will have to spend trillions of dollars on adapting to this new environment and there is no certainty it will work out. Strong climate actions would minimal effect on the overall economic growth. It would, however, see a transfer of power from the legacy coal/oil industries of the past to the cleantech industries of the future. If we had strong policies on the price of carbon, things might have been different. If carbon was priced by taking into account all the negative effect it has on the climate and its part in air pollution, things would be different. The market forces would find an alternative and we would have entered the clean energy era decades ago. Moving away from coal-based energy sources will have several auxiliary benefits, including cleaner and fresher air. We also need to move from a centralised energy distribution system to a decentralised providing more competition, lower infrastructure cost and efficient use of resources. Wind turbines and photovoltaics are inherently decentralised sources. Once we have a decentralised energy grid up and running, powered by renewable resources we can simply plug in our transportation network to the gird and reduce greenhouse emission by another magnitude. Electric vehicles are also here and Tesla has rejuvenated an entire industry. To some extent, the future looks bleak but it also looks exciting as we have new challenges to face. The industries of the future are likely to look very different from what they are now. If we work together and share our resources and ideas it’s more than likely we will at least delay the onset of climate change if not stop it.
Climate change is an important topic to discuss. There is so much we don’t know but that true with anything. The aim of this post is to provide an overview, a cheat sheet if you will. Over the next few posts, I want to dive deep into some other major discussion including current climate-change policies, technologies in place, best practices and organisations and countries putting up a fight. If you have any particular topic that interests you, shoot a message or leave a comment!