As you may be aware from indications elsewhere on this blog, I offset my carbon emissions. I don’t mean just my travel carbon emissions, but from my whole energy footprint. However, as my 40th birthday approached, I began thinking about offsetting my carbon emissions twice

Why twice? I suppose I could give various justifications for doing so. I could say that the duplicate covers my carbon footprint from the period of my life before I began offsetting. Or I could say that it covers the carbon emissions from non-energy consumption, which are more variable and complex to calculate, such as food and manufactured goods.

2020 was also when I chose to write more specifically about carbon offsetting projects, to help aspiring sustainability advocates understand what they do (and don’t do), and know what questions to ask so we can all keep them honest. It felt synergistic to explore the different offsetting methods at the same time.

Whatever it was, the timing felt right. 

If you haven’t read it already, check out my article Two Simple First Steps to be an Effective Sustainable Traveller. That’s the article where I expand on the two habits I recommend to cultivate the sustainable mindset that will help you understand and apply carbon offsetting in the right context.

View of Rangiroa atolls from airplane window, French Polynesia
Coral reef atolls are at risk from global warming induced sea level rise

Who do I offset my carbon emissions with?

I’ve been offsetting my carbon emissions with Terrapass for many years. This is simply because, at the time I started doing it, they were the only credible carbon offsetting provider that survived the pioneering attempts to create a viable system.

At first, I thought I would fulfil my pledge by simply doubling my calculated energy footprint at Terrapass, and then that would serve as my 2x emissions offset. It seemed pointless to do it any other way. After all, any credible offset provider would have a carbon footprint calculator. How else would you know that you’re offsetting ‘enough’, rather than just some arbitrary amount? 

But if so, what would be the point of filling in two calculators? 

However, as 2019 wore on, an alternative I never thought of popped up. The fuchsia branding of CHOOOSE began popping up all over my social media. CHOOOSE has the endorsement of the UN Framework Convention on Climate Change (UNFCCC), yet there’s no carbon calculator to be seen. I was intrigued. How is the accounting done? 

Curious, I checked them out. Their alternative was ingenious. So, when 2020 actually arrived, I ended up carbon offsetting with two different providers after all. And I could see how they each could appeal more to a different personality.

There are basically two approaches for estimating individual carbon emissions

The difference between the way Terrapass calculates it, vs CHOOOSE, can be summed up in this very common scenario:

You are out for dinner with a bunch of other people. At the end of the meal, the bill comes. How do you split the bill?

Now, there are cultural differences as to how this should be done. But broadly speaking, there are two approaches. (We can eliminate those cultures where people will battle for settling the whole bill, as there is no one on the planet who can settle the emissions from the entirety of humankind.)

The more accurate way is for each person to calculate for their own food and drinks, plus a ratio of the shared costs, like taxes and tip. 

But the faster way is for the whole bill to be split evenly across the number of people. 

Method 1: For those who hate keeping records

In order to use any carbon footprint calculator, you have to have some record of your energy use, at least for transportation and around the house. 

Now, for someone who is organised (like moi), who have budget sheets and maintenance records and folders for tax receipts and bills, this isn’t an issue at all. However, I am quite aware that the majority of people are the opposite. 

If you are the kind of person who finds it difficult to be organised, but you still want to do your part and offset your share of emissions, then a provider like CHOOOSE is the one I would recommend for you. (Actually, as of this article, CHOOOSE is the only provider that I know of who does it this way.) 

Not only that, all of their projects carry Gold Standard verification. This means that the verification is extremely conservative. That can mean some legitimate carbon projects might not qualify as Gold Standard. On the other hand, the rigour means that as checks and balances tighten and expectations increase, a Gold Standard offset credit is more likely to still pass muster. Gold Standard projects also deliver additional sustainability benefits, other than just climate benefits.

How did they get around the need for a personalised carbon calculator?

It’s actually quite obvious, once they’ve done it.

Data already exists with folks at the UNFCCC about per capita emissions for various countries. Some countries have more precise data than others, of course. But roughly speaking, national scale data exists. You’ve probably seen the figures comparing different countries’ climate change contribution, and per capita emissions statistics. 

Instead of having each person calculate their own emissions, CHOOOSE simply uses this existing data, and estimates a country-corrected carbon footprint for you. Basically, it assumes you are typical of your country, and calculates the carbon emissions for the average person in your country. 

Dandenongs eucalyptus forest, Victoria, Australia
Don’t miss the forest for the trees

CHOOOSE does not have country-corrected amounts for everywhere, though. Certain countries, like in Europe or the USA, do get their own footprint values. But most other countries (including Malaysia) are just averaged out together, and are given a ‘World Citizen’ averaged footprint. 

Does this method have shortcomings?

In a way, yes. In our dinner example, one guy might have ordered a salad and another guy might have ordered the Wagyu steak. This approach means the total gets averaged out. The guy who had the steak would be paying less than the cost of his dinner.

My offset with CHOOOSE as a Malaysian is $3.50/month, totalling to $42 a year (offsetting ~11,000 lbs CO2e). This is via the default projects that fund replacement of fossil fuel use with renewable energy in developing countries*. However, as you’ll see later in the article, my actual emissions footprint is usually more than 11,000 lbs CO2e. Which means, another person like me who chooses to offset with this approach, would be under-offsetting.

But let’s not get picky. If the simplicity of the method means that the obstacle of boring data review is removed for many, something is better than nothing. This is also a great interim option for those who want to do it the accurate way (see below), but haven’t started keeping records yet.

Method 2: For those who don’t hate spreadsheets

If you actually enjoy creating spreadsheets and maintaining records, then you would probably find using a carbon calculator perfectly fine – or even enjoyable! Two carbon calculators that I find sufficiently user-friendly are the ones at and

Not that you actually need to make a spreadsheet, to use a carbon calculator. What I mean is, you’re probably the sort of detailed-oriented person, who would already have the necessary information.

Why should I bother with a carbon calculator?

Suppose you are ambivalent about keeping records. Are there good reasons to go through the extra trouble of using a carbon calculator?

If you travel by air at least some of the time, then I would say yes.

As I mentioned above, CHOOOSE estimated my carbon emissions at 11,000 lbs CO2e. But my total calculated energy footprint in 2019 was 22,223 lbs CO2e, twice as much as the average.

This is because that year I made 1 trip to the Pacific, and 2 regional trips (to Australia and India). It is immediately obvious from the screenshot below that these flight emissions are the reason for the discrepancy between the two methods. The average Malaysian does not typically make this many flights, nor so far. I would, in fact, be under the average were it not for the flight emissions.

Offset your flight emissions!

Teja on the Horizon personal carbon footprint 2019
The carbon footprint of long-haul flights is clear.

What are my other reasons for using a carbon calculator?

  1. I want to be able to compare my energy use between years. Carbon offsetting is not the solution for the climate crisis. It is just a system for measuring carbon emissions, and then investing in solutions that actually reverse the climate crisis. I use a carbon calculator to see how much effect different lifestyle changes have on my carbon footprint.
    • This article, which I plan to update every few years, gives an overview for how my carbon emissions have reduced over the years.
  2. I want to blog about my journey towards a low carbon lifestyle. So, I need more specific emissions data so that I can reflect on the energy transition momentum.

Are the various carbon calculators different?

The emissions output don’t vary by much. Essentially, the science behind carbon estimations have more or less settled, notwithstanding details such as radiative forcing for flights etc. For conventional vehicles, databases have also been compiled by now from manufacturers and service providers. Therefore, the algorithms underlying carbon calculators for different activities (e.g. flights), and the main assumptions (e.g. a certain vehicle model’s fuel efficiency), are more or less consistent.

The remaining variations are negligible for what you want this calculation for. The $ amount of your corresponding offset will change more by the type of offset project, rather than with a more accurate carbon emissions estimate. The lifestyle decisions that you make to reduce your footprint as a result of the calculation, will also be unlikely to depend on these differences. Remember, although I used the example before, the point of carbon offsetting is not to “settle your bill” with the planet. It’s actually to drive change in the global energy systems.

Therefore, the differences are really mainly in the user interface. Comparing between Terrapass and Carbonfootprint specifically, the most meaningful difference between them is that the latter offers calculation for secondary emissions. That’s pretty much it.

Secondary emissions are the carbon footprint of non-energy consumption, like food, electronics etc. I personally feel that these calculations vary too much to reliably estimate. Carbonfootprint estimates it by $ spend alone, which would require assuming many things about the products and services. My view is that it’s better to address them from a zero waste or circularity perspective, rather than a low carbon one.

Detailed instructions for how to use a carbon calculator

If you’re intimidated by carbon calculators, don’t worry. I’ll walk you through it here.

Since I primarily offset with Terrapass, and since it doesn’t really matter which calculator you use, I will be referring to Terrapass’ calculator interface. But the data needs are going to be similar for other calculators.

Generally, you should expect to see the broad categories of our modern energy use in a carbon calculator:

  • Home energy – common sub-categories are electricity use, maybe also cooking gas or other gas uses.
  • Personal mobility – motorised transport like a car, motorbike, sometimes even boat!
  • Mass mobility – trains, ferries, buses, etc.
  • Air travel.

Incidentally, this also means that you could choose to start calculating your carbon footprint for just one or two categories to start with, if you’re not ready to do all of them.

I’ll now go into each category and tell you what kind of records you’ll need to complete the sections.

Solar panels at a chalet on a remote Polynesian motu
Solar power on a remote atoll in Rangiroa

1. Air travel

I start with air travel not just because it is often the biggest footprint activity in the list, but also because it is the easiest to complete.

You literally just need to remember where you took off, and where you landed. Seriously, that’s it. I remind myself of my flights by looking at my calendar for the past year.

View of airplane wing from window seat
Offsetting air travel emissions

If you want to start with offsetting just your flight emissions, but you specifically want to drive decarbonisation efforts in aviation, there is a third carbon offsetting option you can look at. Flightnook carbon credits funds the supply chain for lower carbon aviation fuel so that it can at least partially replace legacy fuel.

2. Personal vehicle emissions

This is also an easy category, if you’re a good vehicle owner and get your car/truck/motorbike serviced regularly. The reason is that the service invoice usually will have your mileage written on it. If you keep these in a folder, then you just need to take the difference (maybe pro-rate it, if you didn’t exactly service the vehicle annually), and that’s what you put into the calculator!

Otherwise you’d have to make a note of your vehicle mileage every time you do this, and calculate the difference from what you noted last year.

Mileage record from car maintenance invoice
Easy mileage record

You also usually need to key in the vehicle’s make and model, as well as year of the vehicle (newer vehicles are more fuel efficient). That said, from playing around with the calculator, getting the model wrong does make a noticeable difference, but getting the manufacturing year wrong doesn’t really. Which is good, since who doesn’t know what car they’re driving?

Additionally, Terrapass’ calculator rounds to the nearest 2000 miles. Ever since I started taking the train more, I drive a lot less than this in a year. So, what I do is that I consider the remainder to cover the ad hoc ride shares, buses, and taxis that I take while travelling, and don’t calculate these in the public transit section.

3. Public transit

Emissions from public transit is a bit trickier to fill in, because the calculator asks for distance travelled, but you usually don’t know the exact route. However, the good news is, accuracy matters less for this category because the carbon footprint for public transport is so slight that even if you get it wrong, the total emissions value won’t change all that much. Try it and see!

I estimate my train commute to work by querying online maps for the distance. I compensate for route variations (sometimes I take different rail systems), or trips I forgot, by assuming a flat frequency of train use per week, even though this is more than I will really take due to public holidays and travel.

Puffing Billy steam train
Thankfully trains are no longer coal-fired…

4. Home energy use

Depending on how your home is set up, this can either be very easy, or a bit of a hassle.

A fully electrified house like mine, where even the stove is electric, only requires one kind of record: my electricity bills. All you need to do is total up the kWh consumption for the year, and that’s one of the data you need.

Electricity usage kWh
Easy record of electricity consumption

The next part is about estimating the carbon footprint of your electricity grid. Terrapass will ask you for a US zip code (because it is US-based), whereas Carbonfootprint will ask for your country and then suggest a default multiplier. This is to properly reflect the power supply mix at your location, since the carbon footprint of 200 kWh delivered via coal-fired power stations is not the same as 200kWh delivered via a combination of gas and solar.

Now, I don’t live in the USA. So, the way I answer this question is by choosing a US state that has a more or less similar power generation mix as Malaysia (by internet research). And I’m not sure if it matters to the algorithm, but I also consider similarity of climate. Florida more or less fits the bill – majority gas with some coal the last I checked – so I put in a Miami zip code.**

If you have additional energy types at home, like cooking gas or heating oil, then this section gets trickier because you probably have to keep extra records. For example, how much cubic feet of gas? How many gallons of oil? So, you’ll need to keep receipts for these purchases. Or maybe just do it for a year, and then just assume it stays the same if you haven’t changed anything.

US style corporate management promotes senior managers who see staff in terms of their job grade, like parts in a machine. So if two people happen to be in the same job grade, therefore they must be interchangeable.

As a kind of LOTR fan, I have to nitpick the phrasing and clarify that the reason why the One Ring was the least dangerous with a hobbit, is because hobbits just want to live life and get along, ie hobbits aren’t tempted to “rule them all”.

The option that isn’t carbon offsetting

There is a third carbon capture option that a lot of environmental activists like. This is to donate money to NGOs that fund ecosystem restoration, like rainforests and mangroves. An example is the Rainforest Trust.

If we go back to our dinner analogy, this is like eating at one of those ‘pay whatever you like’ restaurants. It’s based more on how much you appreciated the meal, rather than how much it cost to make it.

Are these projects helpful? Yes. From a biodiversity standpoint, from a coastal protection standpoint, even from a global warming standpoint, because priority ecosystems like forests and mangroves also absorb carbon dioxide.

But are these projects carbon offsetting? No. Because there is no link between what you donated, and the carbon removed from the atmosphere.

Foliose coral amongst branching coral in the Great Barrier Reef
Ecosystem restoration is important, but is not necessarily the same as carbon offsetting

Why does this matter?

Doesn’t it ultimately remove greenhouse gases from the atmosphere anyway? Why do we need to correlate a purchase with CO2 equivalent (CO2e) removed?

The reason is because carbon offsetting is not truly about cancelling our personal emissions. It is about modifying our modern civilisation so that the impact of carbon emissions is considered in energy systems.

So yes, for the big picture, support ecosystem restoration. Shift towards a plant-based diet. Take public transport. Bike more. But also offset your carbon emissions. (And help hold these projects accountable.)

For preparatory reading, and links to other articles in this Carbon Offsetting series, see articles below:

The elephant in the room for travellers

A question that is especially pertinent for travellers is whether air travel itself has become unethical. After all, you can see from my carbon emissions summary that flight emissions take the lion’s share of my carbon footprint. Even if you take into account that my other emissions would increase if I’d stayed home, the increase would still not be anywhere near my flight emissions.

Here’s where I’d like to talk about Step 2 in one of my earliest articles, Two Simple First Steps to be an Effective Sustainable Traveller, and the effect of intention.

How often do I travel, and why?

Travel does contribute a lot of flight emissions. But travellers create connections between people. And those connections are crucial because our pressing problems today are global in reach. But just because it needs to happen, doesn’t always mean that you need to do a lot of it.

A lot of friends assume that because I have a travel blog, and post travel content on its social media channels, I must travel a lot. Here’s my carbon footprint from 2018:

Teja on the Horizon personal carbon footprint 2018
Only 1 fewer Pacific trip nearly halved the flight emissions.

I only took two trips that year, 1 trip to the Pacific and 1 domestic. The flight emissions are almost entirely due to the Pacific trip. And the Pacific, of course, is a region that is very difficult to visit without air travel.

Yet, despite taking only two trips in 2018, I still have a writing schedule that easily extends into 2021. If I take into consideration my 2019 trips, it goes further. How can this be?

You see, after my odyssey in Nepal, and after writing about it, I discovered unexpected things.

Knowing that I would be blogging about it, I had paid more attention. Because I was more intentional, my enjoyment improved, and I tried more things. And so I had more stories.

Because I have so many stories to tell, I find that I don’t crave to travel as much. And because travelling differently changed me, and because I now don’t crave travel as much, I can give back to projects at home, e.g. training to be an EcoDiver.

A small thing, intention. Yet how powerful it is, when repeated.

When you focus on intention, frequency takes care of itself.

We fly for many reasons. Some of them are trivial. Take a flight out on the weekends just for a night out on the town, or a meeting you could have done virtually.

Perhaps for those who previously lacked the awareness to feel shame, the flight shame movement is good for raising mass awareness to think about the purpose of their air travel. However, this is an introspection that is largely only relevant to the privileged 1% of humanity.

Some of us have international businesses. Some travel for work. Still others visit families separated by vast distances. And some nations can only be reached across oceans.

Air travel forms crucial links for mountainous or archipelago regions, and often is the most sustainable means of transport for these destinations. Substituting air travel with rail in some regions would entail opening up valuable forest land. For other regions, the alternative to air travel are cruise ships, which are worse than flying.

But if you know why you’re going, then that is not a wasteful trip. If you know why you’re going, you can make better choices for how. And if you know why you’re going, you may realise you need to make some life decisions to eliminate the travel – for example, move to the people you love, or invest to enable more remote working for your business. And if you can’t, at least you can look ahead to when you can.

So I repeat my two simple steps for a sustainable traveller: Reflect on your intention, and know your carbon emissions.

Wind turbine field in the Atacama desert
Wind power in Chile


*There is also a new, more expensive, option to achieve the same emissions offset. These are via projects that actively draw down past carbon emissions from the atmosphere to immobilise them. At the moment, I haven’t chosen these projects, as I personally want to support efforts in structural change of the energy systems. But eventually I would probably start choosing a mix of both.

**2023 update: I no longer have to do this part of the calculator, because Malaysia’s national power provider has launched a subscription for renewable energy, with Renewable Energy Certificates (RECs). As my home energy consumption is very low, it is very affordable for me to subscribe to the programme, which means I am virtually buying 100% renewable energy at home.

This is an example for how to use carbon offsetting correctly. First, as one of the tools to drive energy systems towards renewable projects. Eventually, they become the more financially viable ones. Then they start becoming a normal part of the energy system. This is when you switch to sourcing it directly (rather than continue sourcing legacy energy and offsetting its emissions).

This article is not sponsored by Terrapass or CHOOOSE or any entity cited. If you found it useful, please share widely.

"2 Best Ways to Offset Your Carbon Emissions - Based on Personality!" Article on sustainable travel blog Teja on the Horizon

8 Responses

  1. Ranvijay Singh says:

    Thanks a lot for this is such a well-explained article. It’s really helpful.

  2. Pete says:

    As someone in the aviation industry I found this a very interesting read – a lot to think about!

    • Teja says:

      Aviation is one sector that definitely needs considerable thought and work to decarbonise, similar to steel and cement. Thanks for coming by and commenting!

  3. This is such a well-explained article. I loved the read. Thanks!

  4. Ashley says:

    Great article! I think it’d be great if we could all keep track of our energy footprints, this would probably push more people to be greener. Thanks for sharing!

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