Jadavpur University Alumni Association Hyderabad Chapter

Dr. Chanchal Sarbajna,  
AMD/Department of Atomic Energy, Begumpet, Hyderabad-500016.  

Carbon footprint is the sum of all emissions of carbon dioxide, which were induced by our activities in a given time frame. Usually a carbon footprint is calculated for the time period of a year. The total amount of greenhouse gases produced to directly and indirectly support human activities, is usually expressed in equivalent tons of carbon dioxide(CO2). For example, when we drive a car, the engine burns fuel which creates a certain amount of CO2, depending on its fuel consumption and the driving distance. When we heat our house with oil, gas or coal, then we also generate CO2. Even if we heat our house with electricity, the generation of the electrical power may also have emitted a certain amount of CO2. When we buy food and goods, the production of the food and goods also emits some quantities of CO2.  
Carbon dioxide is a so called greenhouse gas causing global warming. Other greenhouse gases which might be emitted as a result of our activities are e.g. methane and ozone. These greenhouse gases are normally also taken into account for the carbon footprint. They are converted into the amount of CO2 that would cause the same effects on global warming (this is called equivalent CO2 amount).  

Few people express their carbon footprint in kg carbon rather than kg carbon dioxide. We can always convert kg carbon dioxide in kg carbon by multiplying with a factor 0.27 (1'000 kg CO2 equals 270 kg carbon). The carbon footprint is a very powerful tool to understand the impact of personal behaviour on global warming. Most people are shocked when they see the amount of CO2 their activities create! If we personally want to contribute to stop global warming, the calculation and constant monitoring of our personal carbon footprint is essential.  

A carbon footprint is made up of the sum of two parts, the primary foot print and the secondary footprint.  
1. The primary footprint is a measure of our direct emissions of CO2 from the burning of fossil fuels including domestic energy consumption and transportation (e.g. car and plane). We have direct control of these. The following table shows us the way to calculate our individual primary footprint of the most common consumptions.

2. The secondary footprint is a measure of the indirect CO2 emissions from the whole lifecycle of products we use those associated with their manufacture and eventual breakdown. To put it very simply the more we buy the more emissions will be caused on our behalf. Our decisions on some of the following add up to our secondary footprint.  

1. We use mostly seasonal food- or not.  
2. We buy local food and goods - or not.  
3. We think of packaging while buying things - or not.  
4. We buy new furniture and appliances - or second hand.  
5. The things we use get recycled or composted - or not.  
6. We try to avoid burning of fuel on transportation - or not.  
7. We try to use common vehicles for travel - or not.  
8. We bring a bag when we go shopping - or require a plastic bag from each shop  

The direct consequence of increased carbon foot print is Global Warming and Climate Change. Global Warming is the gradual increase in temperature of the Earth's surface. 

Over the past two decades the effect has become more marked. Considerable evidence exists that most of this warming has been caused by human activities. That is to say we have altered the chemical composition of the atmosphere through a build up of greenhouse gases primarily carbon dioxide, methane, and nitrous oxide. This means that a cloud is building up around the earth under which heat is accumulating instead of dispersing in the atmosphere. If we do nothing, rising global temperatures will cause sea level to rise and alter local climate conditions, affecting forests, crop yields, and water supplies. It may also affect human health, animals, and many types of ecosystems. Deserts may expand and some of our countryside may be permanently altered.  

So we need to recognize our personal impact on global warming. There are a number of ways to reduce our carbon footprint and live a more earth-friendly lifestyle. Some of them are more feasible than others.  

1. Wash clothes with cold water, hang dry laundry rather than putting it in the dryer when it's warm outside. Clean the lint filter in the dryer every time.  
2. Take mainly cool showers if we are healthy or if we want to boost up our immune system and save energy and water at the same time.  
3. Replace any incandescent light bulbs with Compact Fluorescent Light Bulbs (CFL) or Light- Emitting Diodes (LEDs). bulbs are more expensive, but replacing just one incandescent light bulb will save 150 pounds of carbon dioxide and, because it lasts eight to 15 times longer than an incandescent bulb, save approximately US$30 over the course of its lifetime. CFLs contain small amounts of mercury and as such must be handled as hazardous waste when discarding. Some cities have hazardous waste pick up programs and companies such as Home Depot accept inactive CFLs bulbs for safe disposal. LED lights are highly efficient and are able to reproduce the soft light of incandescents. They also contain no mercury and last six times longer than CFLs. This will save on power bill too. 
4. Use the microwave less Microwaves use a lot less energy than conventional ovens and stoves,  especially for heating water. 
5. Turn off lights when they aren't being used, even when we leave a room for a short period of time.  
6. Clean or replace air filters on AC unit at least once a month.
7. Set refrigerator temperature at 36-38 degrees and freezer to 0-5 degrees. Pack refrigerator tightly to reduce the amount of cooled air. Ensure that the refrigerator is leveled properly to ensure that it operates efficiently. If we are buying a new refrigerator, ensure that it is Energy Star approved.
8. Turn off the faucet while brushing teeth. We will save 25 gallons of water a month.
9. Use a low-flow showerhead and faucet aerators to conserve water.  
10. Reverse indoor ceiling fans for summer and winter operations.  
11. Buy used furniture because there is a surplus of it. It is often cheaper than new, with the exception of some antique furniture.  
12. Use cloth napkins instead of paper ones, although washing cloth napkins uses water too.  
13. Unplug electronics: Most electronics still use some energy even when turned off. This 'standby mode' or 'phantom load' drains up to 10 percent of electricity used in most homes.  
14. Use surge protectors to make it easier to unplug lots of things at once when we leave a room.
15. Turn off computer when we're not using it. Or adjust computer's power management to reduce the amount of power it uses while idle. Do this on any computer's we have access too.
16. Reduce the need to copy and print. When we need to, copy and print on both sides of the paper
17. Use a ceramic coffee mug instead of disposable cups  
18. Drive during non-peak hours If we avoid heavy traffic we will not spend a significant amount of gas during stops.  
19. Buy local. Buy goods that were produced locally rather than transported across long distances.