Are we following the right footprints?

Energy can neither be created nor destroyed. It can only be transformed from one form to another.

We saw in our previous articles and discussions that every energy conversion has an impact on the health, safety and environment (HSE) and creates a by-product. This impact was not understood for most of human civilization period. Within the past 75 years we have not only identified the impacts but also made several efforts to measure and minimize them. The impact that we are observing unfortunately affects our survival, hence it is essential to quantify the impact, as it then leads to measurable efforts and also to calculate the improvement.

From this article onwards I will try to show the impact of energy on the environment and sustainability and vice versa. I will try to keep my attention on energy and try to learn myself as we go. I understand that being such an intricate complex topic which is linked to so many other domains such as climate change, sustainability, pollution, economics, it is easy to digress, but I will try to persist my focus.

Quantify Impact: Ecological Footprint

There are many ways to quantify our impact on the environment. The measurement of emission from cars started with the Clean Air Act (1970), at least in the United States[1]. All over the world very strict guidelines have been laid out for the emission control from any internal combustion engine. The cars are mandatory to have inspections on their emissions [1]. This slowly has led to very strict regulations which begin from the manufacturing of the engines.

This was a big step as for the first time we were trying to measure the amount of harm we are causing to the environment based on the exhaust gases. As a matter of fact this is still an important measure for the performance of an internal combustion engine. The only problem with this method is relatability to the general public. Here is an example of the emissions test report. ( Source: Except for the part that says PASS it is not easily understandable for a person who does not have knowledge of the terminologies.

Figure 1: A generic exhaust emission test report

Ecological Footprint

Currently, one of the most effective ways to quantify our impact on the ecosystem is Ecological Footprint (EF). EF is a measure of the demands made by a person or group of people on global natural resources. The concept was brought by Dr. William Rees in the early 1990s. It is a beautiful concept and provides the outcome in a very tangible way. Unlike the earlier methods of finding the amount of CO2, CO or SO2 produced from a vehicle which can be very condescending to an average person, all of a sudden a new concept was brought forth which showed in very simple terms

  1. How much hectare of land is required to achieve any given style of living?
  2. What is the tolerance limit of the resources in terms of the calendar year?

I used the ecological footprint calculator available on and got the following results

  • If everybody on Earth lived like you, by April 1 we would have used as much from nature as Earth can renew in the entire year. This is your overshoot date.
  • If everyone on Earth lived like you, we would need 4 Earths.

As much ashamed I am from this answer, it gives me a result which I can very easily understand. Dr. William Rees of course did a lot more than just create a terminology. He is a leading bio-ecologist who now works towards sustainability and global ecological trends [2].

Another term that Dr. William Rees introduced, “Bio-capacity”. This defines the capacity of a given biologically productive area to generate an on-going supply of renewable resources and to absorb its spillover wastes.

If the ecological footprint for an entity is higher than the bio-capacity, there will be un-sustainability. It is a fairly simple concept which creates a very big impact on the way we think.

Consider for a moment 2 different examples.

A person living on a farm and a person living in a city. The person living on a farm can grow his own vegetables and is very much self dependent when it comes to resources. While on the other hand the person living in the city is heavily dependent on the supply chain that brings food to the grocery store he shops from. Since the person in the farm can renew his resources, his overshoot days would be very high and he does not need more land. The person in the city will reach his overshoot days very quickly since he is dependent on areas outside the city for growing vegetables.

Not having read Dr. Rees’ entire work, I am sure he has considered many other variables in account such as technological advancements, organic farming, faster transportation and storage etc. Having said that, a very simple outcome of this research is that if an entity can become self-sufficient from its own natural surroundings, it will create a much larger positive impact on the ecological system.

Here is a chart from showing the Ecological deficit or un-sustainability throughout the world. The countries marked in red are in an un-sustainability trend as compared to their entire ecological footprint and biocapacity while the ones in green are sustainable. 

Ecological Deficit = Biocapacity- Ecological Footprint

Positive Ecological Deficit = Sustainable Environment

Negative Ecological Deficit = Unsustainable Environment

Carbon Footprint

From this definition of ecological footprint, another term came into existence which is now very well known, “Carbon Footprint”. Carbon footprint gives the amount of carbon released in the atmosphere as a result of any activity performed by an individual or an entity. Living in a home, driving a car, flying in an airplane all have a carbon footprint associated with them. This term was extremely popularized by a major Oil & Gas firm in the early 2000s. Carbon footprint soon became a household known terminology and can be seen even while booking airline tickets. I will not dive deeper into carbon footprint as it is a relatively well known concept and can be easily researched.

Concerns with Ecological and Carbon Footprint

Calculating Ecological and Carbon footprint is a very effective way to describe how much damage we are doing to the earth.

However, I have concerns with these techniques. I am sure others have also thought and written about these issues. In no way, am I saying that these are inefficient methods, but there are certain flaws with these techniques which we should always keep in mind. For example

  1. Calculating the ecological footprint or carbon footprint requires certain assumptions. The carbon footprint calculator on the United States Environmental Protection Agency website ( provides the assumption it considers in calculating the carbon footprint for various scenarios. The average emissions for a typical vehicle are taken as 10,484lbs CO2e/vehicle. (CO2e or Carbon dioxide equivalent means the number of metric tons of CO2 emissions with the same global warming potential as one metric ton of another greenhouse gas, and is calculated using Equation A-1 in 40 CFR Part 98.). The source for this metric is the USEPA report in 2009. It can be seen that the EPA had several updates to their regulation since 2009 ( There have been so many updates to the engine performance and combustion science since 2009 that these emission numbers may be obsolete.
  2. Carbon footprint can lead to many misleading conclusions. For instance, a user may switch to an electric car to reduce the carbon footprint. But if the electric car is being charged using a thermal power plant or an inefficient diesel engine generator, the overall carbon footprint may be higher. I am not claiming to perform any calculation but sometimes an individual act of reducing carbon footprint may have an indirect negative impact, especially in a world where we are heavily dependent on crude oil and natural gas. This indirect negative impact can cause more damage too, in some cases.
  3. Carbon footprint can also lead to mischaracterizing or misrepresentation. This is a debatable topic. Taking the previous example, a person with an electric car can be considered to be an environmentalist not realizing that he may be having a bigger house or other cars which actually increase his overall carbon footprint. My point being that just looking at the carbon footprint from one aspect may not be worth it.

Another example of misrepresentation is in the case of a global scale. For large global corporations having locations all over the globe, the overall carbon footprint for the organization may be neutral or even negative. But that may not mean that they are not impacting the global carbon footprint. In fact the overall carbon impact on the earth might still be the same, it just is now outsourced to some other group.

Consider an example shown in Figure 3. Company A puts trash cans for its employees to comply with cleanliness guidelines (and reduce carbon footprint). Company A asks Company B to take care of trash so that it is not liable for it anymore. Company B, instead of disposing of the trash properly, burns it. This is a serious violation on their end. But does it mean that Company A is an environment friendly company? In my opinion not. Of course it is not possible for Company A to track what each of its vendors or service companies does (there should be governing authorities which keep a track on every company and their activities). But it should also not be allowed for Company A to call themselves as “Environment friendly” or “Carbon Negative”. This leads to huge misconception among the general public.

The overall impact of our every action leads to the overall impact on our one and only home, planet Earth and we all are responsible for it. 

Figure 3: Various ecological interactions of humans indicating a comparative carbon footprint. A reduction in overall carbon footprint is essential rather than simply passing the buck from one to another.

So if measuring and lowering ecological and carbon footprint is not the complete answer, then what is the answer? Let me see if I can answer that.

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