Office Location

Bandar Parklands, Klang

Call Us

+6013-811 8004


Carbon Sustainability

What is a carbon footprint?

The term carbon footprint crops up a lot these days. What exactly does it actually mean?

Carbon footprint is a horribly abused phrase, so it’s worth spelling out exactly what it means.

When talking about climate change, footprint is a metaphor for the total impact that something has. And carbon is a shorthand for all the different greenhouse gases that contribue to global warming.

The term carbon footprint, therefore, is a shorthand to describe the best estimate that we can get of the full climate change impact of something. That something could be anything – an activity, an item, a lifestyle, a company, a country or even the whole world.

The essential but impossible measure

The carbon footprint, as I have defined it, is the climate change metric that we need to be looking at. The dilemma is that it is also impossible to pin down accurately. We don’t stand a hope of being able to understand how the impact of our bananas compares with the impact of all the other things we might buy instead unless we have some way of taking into account the farming, the transport, the storage and the processes that feed into those stages. So how should we deal with a situation in which the thing we need to understand is impossibly complex?

One common response is to give up and measure something easier, even if that means losing most of what you are interested in off the radar. The illusionist Derren Brown refers to one of his core techniques as the misdirection of attention: by focusing his audience on something irrelevant he can make them miss the bit that matters. Examples include an airport waxing lyrical about the energy efficiency of its buildings without mentioning the flights themselves.

The same thing can happen by accident. If you settle for a toe-print, there is a very good chance it will misdirect your attention away from the big deals. An alternative response to the dilemma, and the approach that this book is all about, is to do the best job you can, despite the difficulties, of understanding the whole picture. My work is about making the most realistic estimates that are possible and practical, and being honest about the uncertainty.

CO2e? What’s that?

Man-made climate change, or global warming, is caused by the release of certain types of gas into the atmosphere. The dominant man-made greenhouse gas is carbon dioxide (CO2), which is emitted whenever we burn fossil fuels in homes, factories or power stations. But other greenhouse gases are also important. Methane (CH4), for example, which is emitted mainly by agriculture and landfill sites, is 25 times more potent per kilogram than CO2. Even more potent but emitted in smaller quantities are nitrous oxide (N2O), which is about 300 times more potent than carbon dioxide and released mainly from industrial processes and farming, and refrigerant gases, which are typically several thousand times more potent than CO2.

In the UK, the total impact on the climate breaks down like this: carbon dioxide (86%), methane (7%), nitrous oxide (6%) and refrigerant gases (1%). Given that a single item or activity can cause multiple different greenhouse gases to be emitted, each in different quantities, a carbon footprint if written out in full could get pretty confusing. To avoid this, the convention is to express a carbon footprint in terms of carbon dioxide equivalent or CO2e. This means the total climate change impact of all the greenhouse gases caused by an item or activity rolled into one and expressed in terms of the amount of carbon dioxide that would have the same impact.

Beware carbon toe-prints

The most common abuse of the phrase carbon footprint is to miss out some or even most of the emissions caused, whatever activity or item is being discussed. For example, many online carbon calculator websites will tell you that your carbon footprint is a certain size based purely on your home energy and personal travel habits, while ignoring all of the goods and services you purchase.

Similarly, a magazine publisher might claim to have measured its carbon footprint but in doing so looked only at its office and cars while ignoring the much greater emissions caused by the printing house that produces the magazines themselves. These kinds of carbon footprint are actually more like carbon ‘toe-prints’ – they don’t give the full picture.

Direct versus indirect emissions

Much of the confusion around footprints comes down to the distinction between ‘direct’ and ‘indirect’ emissions. The true carbon footprint of a plastic toy, for example, includes not only direct emissions resulting from the manufacturing process and the transportation of the toy to the shop: it also includes a whole host of indirect emissions, such as those caused by the extraction and processing of the oil used to make the plastic in the first place. These are just a few of the processes involved. If you think about it, tracing back all the things that have to happen to make that toy leads to an infinite number of pathways, most of which are infinitesimally small. To make the point clearly, let’s try following just one of those pathways. The staff in the offices of the plastic factory used paper clips made of steel. Within the footprint of that steel is a small allocation to take account of the maintenance of a digger in the iron mine that the steel originally came from … and so on for ever. The carbon footprint of the plastic toy includes the lot, so working it out accurately is no easy task.

To give another example, the true carbon footprint of driving a car includes not only the emissions that come out of the exhaust pipe, but also all the emissions that take place when oil is extracted, shipped, refined into fuel and transported to the petrol station, not to mention the substantial emissions caused by producing and maintaining the car.

How to Reduce Your Carbon Footprint

On the Road, in the Sky

One of the most effective ways to begin thinking about how to reduce your carbon footprint is to reconsider how much, and how often, you travel.

Drive Less

In November 2017 carbon dioxide emissions from transportation surpassed emissions from electricity generation as the top source of greenhouse gases.  Why? Electricity generation is shifting away from the use of coal to more renewable sources and natural gas. 

Going carless for a year could save about 2.6 tons of carbon dioxide, according to 2017 study from researchers at Lund University and the University of British Columbia — that’s a little more than a roundtrip transatlantic flight. How can you stop using a car? Try taking a train, bus or better yet, ride a bike.

But let’s be realistic. You will likely need to use a car this year. So, when you do, here are some tips to make your trip more climate-friendly: 

  • Go easy on the gas and brakes — driving efficiently can help to reduce emissions. Drive “like you have an egg under your foot,” recommends Brian West, an expert in fuel and engine research from the Oak Ridge National Laboratory, which researches energy use and solutions in the United States.
  • Regularly service your car to keep it more efficient.
  • Check your tires. Keeping tires pumped correctly can reduce emissions. “Low tire pressure will hurt your fuel economy,” Mr. West said.
  • Air conditioning and intensive city driving can make emissions creep up. Cut down on these as often as possible. 
  • Use cruise control on long drives — in most cases, this can help to save gas.
  • Don’t weigh your car down with extra things that you don’t need on your trip.  
  • Carpool — this way, you’re splitting emissions between the number of people in the car.

Buying a New Car?

Shopping for a new car is a great opportunity to consider how you can reduce your personal carbon footprint. When choosing between gasoline, hybrid and electric, there are a number of factors to take into account, which will determine how “clean” your purchase is. The following can help: 

  • Search for cars here, where they are rated by efficiency. 
  • Think about where you will be charging up. How efficient hybrid and electric cars are also depends on what state you live in — different states rely on fossil fuels to different degrees.
  • Weigh up both production and use emissions using this app. (Making electric cars has a carbon footprint, too.)
  • Look for the Smart Way certification.
  • Remember: Cars with lower emissions can often end up costing less to operate.


Fly Less

Fly often? Taking one fewer long round-trip flight could shrink your personal carbon footprint significantly. Think about it this way: If you use public transportation often, and fly home to visit family just occasionally, your carbon footprint might still be relatively sustainable, but if you drive and fly a lot, your emissions will be higher.

If you can’t avoid flying, one way of making up for the emissions caused is to offset them by donating money to sustainable projects, such as supplying efficient stoves to rural homes, or projects which help farmers in India sell crop waste as biomass. Sometimes airlines will give you this option themselves, or you can use a third-party like Atmosfair or Terrapass. (You can calculate the emissions per flight here.) 

On Your Plate

Globally, emissions are linked to what we put on our plates. 

Eat Less Meat

While food systems are complicated, and research is still evolving on what the most environmentally-friendly diet is, experts mostly agree that cutting down on meat, and red meat in particular, is a better choice for the environment. This is because the production of red meat uses a lot of feed, water and land. Cows themselves also give off methane emissions (a harmful greenhouse gas).

For that reason, eating a vegan diet is likely to be best for the environment, say experts. According to a study published in 2017 in the journal Environmental Research Letters, red meat can have up to 100 times the environmental impact of plant based food. (According to some estimates, beef gives off more than six pounds of carbon dioxide per serving; the amount created per serving by rice, legumes carrots, apples or potatoes is less than half a pound.)

Eating a vegetarian or pescetarian diet are also likely to be better for the environment than a diet which includes a lot of meat. Each of these, however, depend on exactly what you are eating, and how much of it. If you replace that meat with dairy, for example, your emissions could rise again. “Deep net fishing can emit as much as beef,” said Marco Springmann, a senior researcher on environmental sustainability and public health at the University of Oxford. Following national health guidelines, with further reductions in meat, fish and dairy (this is similar to a Mediterranean diet) is a good option too, Dr. Springmann said. These diets can also have health benefits.

Overall, eating low down the food chain as often as you can is a probably a good way to reduce your carbon footprint and stay healthy, say experts. That means filling your plate with vegetables, fruits, grains and beans. For meat-lovers, even swapping carbon-intensive meats like beef and lamb with chicken can make a difference. Better still, swap a few meals per-week to vegan or vegetarian. This protein card can help you make climate (and wallet) friendly choices at the grocery store.

Weighing Your Options

When it comes to food, most greenhouse gas emissions happen during production, rather than transportation: What you eat is more important than where it comes from. But eating local can still make a difference. 

Fewer food-miles can mean fewer emissions. The complicating factor in eating locally happens when you start to consider how the food got to you, not just from how far away it came. “This ‘eat local’ argument, I would take it with a pinch of salt,” Dr. Springmann said. Tomatoes brought a short distance to a farmers market by truck, or shipped further to the grocery store by a train, could release similar emissions. (The transportation you take to get your tomatoes, and bring them home, also matters.) 

What about local meat versus imported vegetables? Eating only locally grown food for one year would save the greenhouse gas equivalent of driving 1,000 miles, but eating just one vegetarian meal a week for a year saves 160 miles more than that, according to one study from researchers at Carnegie Mellon.

How about organic? You might choose organic if you prefer to eat produce grown with fewer chemical pesticides, but when it comes to reducing your carbon footprint, you’re better off shifting to low-impact, plant-based foods, according to a recent study published in the journal Environmental Research Letters. The study found that organic systems use less energy than conventional ones, but they often require more land and, therefore, emit similar greenhouse gas emissions.

Waste Less

This is a big one: on average, Americans waste around 40 percent of the food they buy. 

Luckily, there are simple solutions to lower your food waste (and these tips will save you money, too.): 

  • Take stock. Organize your fridge regularly to check on what you already have, and make grocery shopping lists before you go to the store to prevent buying things you don’t need.
  • Be wary of bulk. Low-priced food might seem like a good deal, but it’s not if you don’t end up eating it before it goes bad.
  • Plan. Don’t cook more food than you can eat. Account for the right amount of food for the number of people eating, and adapt recipes to your needs.
  • Get creative. Reuse leftovers instead of tossing them.
  • Freeze. Extend the life of your food, including additional portions, as well as produce like fresh herbs, by freezing them properly.  
  • Doggie bag. Take home half of oversized restaurant servings. 

What to Eat On. Skip the disposable dishes and wash your dinnerware instead. Washing dishes, whether it is by hand or in a dishwasher, is likely to be more environmentally friendly than using disposable ones (assuming your dishwasher is energy efficient). If you do need to use disposable plates, bowls and cutlery, there are climate-friendly options (look for compostable or biodegradable options). If you order takeout, wash and reuse the plastic containers that food often comes in.

In Your Home

There are simple changes you can make at home that will save you energy, and money. 

Heat, Lights and Appliances

In the average American home, 25 percent of energy is used to heat spaces, 13 percent is used to heat water, 11 percent is used for cooling and the remainder is spent on appliances, according to estimates from the Natural Resources Defense Council. Making even small changes to these can make a big difference, said Noah Horowitz, a senior scientist and director of the N.R.D.C.’s Center for Energy Efficiency. “There’s a lot you can do without having to pick up a hammer or write a check,” he said. (This calculator can help you work out your energy usage before and after you make these changes.) 

  • Turn down the heat. Use a programmable or smart thermostat, if you have one. Keep blinds closed to help keep temperature stable inside.
  • Turn down your water heater — 120 degrees Fahrenheit is sufficient.
  • Turn off lights and appliances when you’re not using them. Turn off appliances at the power outlet to reduce even more energy. Putting them to sleep is second best.
  • Stream movies through your smart TV, not your game console. Smart TVs and their plugins use just a few watts to stream movies, Mr. Horowitz said, but if you use your game console, energy use is about 10 times higher, because they aren’t optimized to play films.
  • Buy a laptop, not a desktop computer. Laptops take less energy to charge and run. 
  • Replace lights. LED lights use up to 85 percent less energy, last up to 25 times longer and are cheaper to run than incandescent lights. About two billion sockets in the United States still have an energy-wasting bulb in them, said Mr. Horowitz. “This is a massive opportunity that we could change almost overnight,” he said. 
  • Don’t set your fridge and freezer temperatures lower than necessary. The United States Department of Energy recommends around 35 to 38 degrees Fahrenheit for the fresh food compartment and 0 degrees for freezers. (And unplug that old fridge in the garage when you don’t need it to chill anything.)
  • Choose renewables. If you live in a state where you can choose your energy supplier, pick one that runs on renewables.
  • Replace old fridges.They are “energy hogs” according to Mr. Horowitz, and can cost you up to $100 extra per year to run. “If it’s 15 to 20 years old,” he said, “it’s a no brainer to recycle it.”
  • Look for an Energy Star symbol when buying new products. This certification means a product has met energy efficiency standards for the United States.

How to Recycle

Americans generate about roughly 258 million tons of trash a year, 169 million tons of which ends up in landfills and incinerators, according to a 2014 report from the E.P.A. That year, American’s recycled and composted 89 million tons of municipal solid waste — this saved the same amount of energy as generated by 25 million homes. But much of the waste that can be recycled still ends up in landfills. 

Here are some tips to make sure your waste ends up in the right place: 

  • Look for a number inside a triangle on the bottom of plastic containers. These indicate what kind of resin was used, and whether the container is recyclable in your state (check your city or state’s website for accepted numbers).
  • Empty and rinse food containers before putting them in the recycling bin. A dirty container can spoil a whole batch of recyclables. 
  • Recycle paper. 
  • Recycle paper and steel and tin cans.  
  • Before throwing away, ask: Can I re-use or repair this?  
  • Donate working electronics. 
  • Recycle broken electronics. Many local electronics stores offer free recycling programs for old goods.
  • Collect dry cell batteries. You should be able to recycle them through your local municipality. 
  • Contact your local car dealer or municipality to recycle car batteries. 
  • Don’t put non-recyclables in the recycling bin. Garden hoses, sewing needles, propane tanks or cylinders, aerosol cans that aren’t empty, hazardous waste and syringes, broken glass and broken light bulbs should all be avoided. 

Make Your Home Energy Efficient

Small changes to the insulation and design of your home — from do-it-yourself hacks to building changes — can help you reduce your carbon footprint at home. Before starting, you can also do an energy audit, or have a professional come in to rate and score your home’s energy efficiency.

  • Seal your home well. Trouble spots can include the attic, windows and doors, where heat and cool can escape.  
  • Insulate your home. This helps keep the temperature stable. There are a range of materials you can use. This guide can help you to choose the right one. A professional energy auditor can help you work out if it’s time to re-insulate. Some insulation does degrade – for example, prior to the 1940s, sawdust and newspaper were used for insulation. You should remove insulation too if it has damage from pests, if it smells, or if it’s wet or moldy.
  • Install a cool roof. This is made of a reflective material which redirects light away from your house, keeping it cool. 
  • Plant shrubs and trees around your home. This is an easy, and pretty, insulation fix, especially for older homes. 
  • Check the energy-efficiency rating for your windows, doors and skylights. Consider replacing those that don’t meet modern standards. 
  • Look into incentives. These may include tax credits and rebates. 

What You Buy

Buying less is the first step. Beyond that, there are simple ways to reduce the impact from your purchases. 

How to Dress Sustainably

According to the World Resources Institute, 20 items of clothing are manufactured per person, per year. This is because of “fast fashion”: clothes that are produced quickly, cheaply and unsustainably. As the price of our clothes drops, the environmental (and human) costs increase.

Here are some tips to minimize your impact when you purchase clothing:

  • Look for a fairtrade, or similar logo. This indicates your clothes were made sustainably. Take a look at this transparency index from the organization Fashion Revolution. 
  • Shop vintage. You’ll be saving money, and the environment. 
  • Ask yourself: How many times will I wear this? Don’t buy clothing that will either wear out quickly, or, that you’ll barely wear. 
  • Consider the fabric. Different materials have different environmental impacts, so that’s something to take into consideration too. Think wool over synthetics. 
  • Donate old clothes. Better yet, use those too old to be donated for other purposes, like sewing projects or cleaning rags. Some animal shelters will take old sheets and towels for bedding material as well. 

How to Shop Sustainably

You shop for more than just clothes, so whatever you’re shopping for — groceries, home goods, toys and whatever else — there are ways to take the climate into account. 

Here are some tips: 

  • Take a reusable bag to the store.
  • Skip the packaging.
  • Invest in quality products that last.
  • Buy carbon offsets. Sometimes, you can’t avoid doing things that contribute to your carbon footprint, but you can support projects and initiatives that offset these emissions. (Remember to be cautious in choosing your offsets, to make sure they are authentic.)

What You Do

In addition to changing your day-to-day habits, exercising your rights as a citizen is one of the most significant things you can do to help the planet. 

Taking climate change into consideration when you vote is a good start. Here are some other tips: 

  • Know your facts. Understanding the science of climate change will help you talk to your family, friends and local representatives with about the issue with confidence. 
  • Find local climate action groups or meetups in your area. Attending these meetings will help to keep you abreast of way you can help in your community. 
  • Speak to your local representative. Suggest things your city or town can do to reduce its carbon footprint, like developing a town action plan, improving recycling, and adopting green energy policies. 
  • Vote on policies that protect the environment. Use your vote to  curb climate change.