Travel Sustainably is a Teja on the Horizon article series reviewing my efforts to travel more responsibly. This first edition reviews new things I tried in my attempt to be sustainable while travelling in CAIRNS, AUSTRALIA – whether by pre-planning, or from the opportunities I found while there. It covers what I did well, what I would keep doing/using, what I would do differently next time, and what I failed to do.

Planning Sustainable Travel to Cairns, Australia

I’ve been to Australia already, before this trip to Cairns. However, in those trips, I hadn’t seriously made the sustainable travel transition, partly because I began by testing out the kit options at home. So I didn’t have anything interesting to say on the topic yet, until Cairns.

Aside from reaching my current defaults re: zero plastic waste travel toiletries (which I’ve chosen to consolidate in my Travel Sustainably article for Tonga), I also make a point to travel with the right sunscreen for a coral reef destination. Especially this one. After all, my reason for coming to Queensland was to see the Great Barrier Reef.

1. Use reef-safe sunscreen for a sustainable tropical vacation

If you’re travelling to a tropical marine destination such as the Great Barrier Reef, one of the most important sustainable travel decisions is to bring reef-safe sunscreen.

Ever since I saw a tank experiment video showing the clear toxicity effect of sunscreen on coral, I’ve switched to sunscreens that have either titanium dioxide or zinc oxide as its UV filter ingredient. But if you were to ask me then, how well the experiment’s result would translate to real-life conditions on the reef, where there will be much more water exchange and distance between swimmer and coral, I would not have been able to say.

Then, the Wandering Redhead became interested in the topic after reading some medical papers on the health effects of oxybenzone. She found a couple of environmental papers on its effects on corals* and, remembering that I’m an environmental scientist in my day job, asked me what I thought.

Of course, I was delighted to get the papers. Journal papers are often behind paywalls and it’s great when a friend just hands over copies!

Yes, non reef-safe sunscreen is bad for corals. And not just a little bad.

It’s gradually becoming common knowledge that certain chemicals in sunscreen are toxic to corals. Many sustainable travel articles, for example the one I linked above, may even tell you how the chemicals affect corals. But it wasn’t until I read the two papers that I understood how bad.

You see, most toxicity experiments look for negative effects at high doses, or over a long period of time. This is because, contrary to popular belief, most things aren’t very toxic. So you need to be exposed either to a lot of it, or for a very long time, and experiments are about trying to find where the line is. How the results would relate to real life, therefore, requires some context adjustment.

However, these particular sunscreen experiments were carried out not in the laboratory, but in the sea. They mimicked the scenario of sunscreen leaching from tourists quite well, and very conservatively. The amounts tested were in parts per billion, i.e. the equivalent of a few drops into an Olympic sized swimming pool. The experiment in one of the papers even tested down to parts per trillion, which is beyond the testing capacity of all but the most advanced laboratories.

In other words, these were gentle experiments. The sunscreen really had the best chance to pass. And it still failed. I don’t mean ‘not super obvious but statistically significant result’ either, which is more common in toxicology experiments. It failed obviously.

View of the main beach of Fitzroy Island resort and other islands beyond from the island jetty. The island rises steeply on the left, covered by green foliage. There is a tourist boat and a floating inflatable platform in the water on the right.

A. It’s bad because of the way it’s toxic.

I’ll come to which chemicals failed in a minute.

Now, bear in mind that studies should be replicated to really have confidence in the results. I haven’t personally read additional papers on that. However, the results reported in these papers were definitely concerning. Despite the extremely low levels of exposure, the damage was still clear and serious. The effect is worse in the presence of light – which is when we would be out swimming on the reef with our sunscreen on.

Some highlights:

  1. The sunscreen caused DNA damage to the coral itself, and cellular damage to the zooxanthellae, which the corals expelled (i.e. ‘bleaching’). Corals will bleach under stress, for instance when experiencing high temperature. But if the stress does not last very long, it can re-absorb its zooxanthellae symbiote. However, if the symbiotes themselves are damaged from sunscreen-induced bleaching, they may not be able to return to the coral, and the coral will starve and die.
  2. The sunscreen was also toxic to the juvenile life stage of coral, which is free swimming (not yet forming reefs that stay put). Cell death was measured at parts per billion levels, which are levels that have already been measured in some marine parks. Needless to say, if this life stage is disrupted, it affects the ability of coral to recover from various other stressors like sewage discharges and global warming.

B. It’s bad because of how fast it’s toxic.

Because these sunscreen chemicals aren’t very toxic to us humans, we tend to assume that even if it’s toxic to another species, it would require sustained exposure at least. It’s an understandable tendency; I assumed it too.

But these experiments show that the effects described above happened very quickly. Cell death of 50% of coral juveniles happened in only 4 hours, whereas the effects on adults and their symbiotes took only 24 hours.

Snorkeler's view down to a coral reef corner around sandy sea bed

What are these reef-toxic sunscreen chemicals?

I use ‘reef-toxic’ because something that’s toxic to one species isn’t necessarily toxic to other species. Please do not panic if you still have a random bottle of sunscreen that you want to use up.

That said, the chemicals studied in these experiments were oxybenzone, octinoxate, titanium dioxide, zinc oxide, as well as other common chemical ingredients in sunscreen (e.g. preservatives, such as paraben). The chemicals that were toxic to corals were oxybenzone and octinoxate, and to a lesser extent, paraben. Titanium dioxide and zinc oxide did not cause the same effects, and that is why they are considered to be acceptable and ‘reef safe’.

Oxybenzone, octinoxate, titanium dioxide, and zinc oxide are all sun blockers. That’s why sunscreen usually just has one of these. When shopping for sunscreen, I personally look for titanium dioxide or zinc oxide, instead of avoiding oxybenzone and octinoxate.

The reason is that the latter may sometimes be listed under different chemical names, because these are shorthand for their ‘official’ chemical names. For example, another name for oxybenzone is benzophenone-3. As someone not particularly partial to chemistry, I choose the easier route!

For a more comprehensive guide to sun protection (sunscreen is really the last resort), check out this article. It’s especially useful for people who are at higher risk of sunburn or skin cancer.

Mineraw reef safe sunscreen
Caveat: ‘Chemical free’ isn’t a real thing. But my point is, look for reef-safe sunscreen.

*The papers were Donovaro et al. (2008), and a Haereticus lab press release referencing a paper by Downs et al. (2015).

How easy is it to get reef-safe sunscreen while in Cairns?

It depends. Pharmacies in Cairns do sell reef-safe sunscreen, but I don’t know if this is a default throughout Queensland. It was also available for free in jumbo size pump bottles at the YHA and was included in my liveaboard package.

On the other hand, this wasn’t the case on the day tour I took. Unlike places like Palau, Cairns does not ban tourists from bringing in non reef-safe sunscreen, so people were using them on these tours. 


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Teja on the Horizon is at Great Barrier Reef.
Teja on the Horizon

Damn it. I was born too early. Marine science has become way more exciting.#coralreef #OceanDecade #ThursdayTales ... See MoreSee Less

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2. Volunteering in the Great Barrier Reef

The Great Barrier Reef is an extremely lucrative tourism destination, but is under threat from global heating as well as other stressors such as agricultural runoff and overtourism. On the other hand, it also has a dizzying amount of organisations working to support it – way, way more than we can dream of in Southeast Asia’s Coral Triangle.

I discovered this because I visited partially as a volunteer. In my travel research I came across many websites, the Great Barrier Reef Marine Park Authority, and the Great Barrier Reef Foundation, Virtual Reef Diver where you can submit your underwater photos to help monitor the reef, and various others.

In terms of volunteering, I signed up with Oceans2Earth. I think they’re the only ones who offer volunteer tourism programs in Cairns. That being said, you don’t have to volunteer to have a sustainable trip to Cairns. You can also help by being a sustainable tourist (see #4 below).

3. Zero waste travel

As far as zero waste travel supplies go, Cairns is a conventional destination. Try not to have to re-supply in Cairns. You can typically get clean drinking water refills anywhere, so it isn’t hard to avoid plastic bottled water.

That said, if you’re dining at budget places, or places that are more geared for takeaways, plastic utensils etc. are still the default. So you’ll get plastic even if you’re dining in at those places. I brought my own containers while going around to have the option to get takeaway without plastic packaging, but this doesn’t always work out perfectly.

What I did realise in Cairns, however, is how easily dehydrated I got there. Yes, even me, who is genetically adapted to tropical climates, and never experienced this as a problem before. It wasn’t too serious; but in hindsight, I’d pack electrolytes in my travel kit.

4. Supporting local businesses in Cairns

If you’re self-catering on your trip to Cairns, where you shop for groceries can make a big difference to how sustainable you can be.

You would most likely look for the main supermarket, which will be the Coles and Woolworths inside Cairns Central mall. But actually, if you plan to shop on a Thursday-Sunday period, the indoor local farmer’s market is just one street across. It’s called Rusty’s Markets, and here you can get fresh, local Queensland produce from local farmers. The variety is fantastic, and it is also much easier to shop zero waste here than in the mall.

When you’re browsing between reef tour packages, you could make a point to look for tour providers that advertise as locally owned. I heard that this means, ‘Cairns local’. Something that may not be very visible to tourists, is that local tour boats have been progressively bought up by corporations, so that these tourist trips aren’t actually local Cairns businesses anymore. They may not even be Australian businesses anymore.

This was a surprise to me, because I thought this sort of thing only happened to us in Southeast Asia. But, the day trip boat I took, Passions of Paradise, is among the last locally owned boats in Cairns.

Additionally, you can also look for the Advanced Ecotourism badge on the tour brochure. Find out what this means on the website.

When shopping for souvenirs, especially souvenirs related to Australia’s Aboriginal people’s culture, check out Ancient Journeys. They’re right on the Esplanade, and are 100% Aboriginal owned, retailing ethically sourced products and artwork from Aboriginal creators.

Sustainable Travel Discoveries in Cairns

When I was in Cairns, there were a few things of notable interest to sustainable travellers. Not necessarily relevant for trip planning, but interesting nonetheless. For instance, Cairns has hosted a Sea Walls: Artists for Oceans ARTivism project, so you can look for the mural series all around the city. Without particularly trying to find them all, I think I still managed to see half.

Selection of the Sea Walls murals in Cairns:

Here are other sustainable topics, and the nuances around them, that I came across while in Cairns.

1. Fish feeding in the Great Barrier Reef

Given the stressed condition of the coral reef at Fitzroy Island, I was surprised that the resort fish feeds at the jetty twice a day. Now, as I wrote when I saw this practice in the context of Rangiroa, fish feeding doesn’t always lead to algae overgrowth over coral. It depends on the context, and the overall ecology.

In Fitzroy, unlike in Rangiroa, it wasn’t just locals chucking leftovers that they might have sometimes to the fish. It’s regular, and seems to be done so that the reef fish flock close to the jetty to delight arriving tourists. However, judging from what I’ve seen of the coral around the island, it seemed to me like the island’s reef needs all the grazer fishes it can get, to graze the algae instead of the fish feed. It doesn’t seem like a good idea to me.

On the other hand, before my visits to Fitzroy Island, I saw another example of fish feeding. Further out in the Coral Sea, my dive liveaboard stopped at a place called Cod Hole. It’s a great dive location because potato cods are known to hang out there. Spirit of Freedom will take down a bit of food to feed the potato cod who are interested, and some of them were.

They explained that they’re one of the few operators still allowed to do so. This is because the practice pre-dated the ban for tour operators, and it’s extremely low impact, as the practice happens so infrequently that the cod are not dependent on it. Licenses for specific reef areas of the Great Barrier Reef are also portioned out among tour operators, so it isn’t something that’s going to be multiplied by a dozen tour operators either.

Diver feeding a tame potato cod at Cod Hole, Coral Sea, during a Spirit of Freedom liveaboard tour on the Great Barrier Reef.

2. Sustainable fishery tours in Cairns

Something I didn’t expect when I came to Cairns, was the mangrove forest. This isn’t just a bit of mangrove fringe, but a long strip wrapping around the coastline of Yarrabah peninsula. It was thick as well; you could boat into it through river channels and it would be all mangrove. I think it was the biggest mangrove forest I’d ever seen – and mangroves are common in my own country.

Mangrove forest edge in Cairns

I saw how extensive it was, because I decided to take a crabbing tour. The tour guide slowed down near the mangroves and I asked to look closer. He obliged and told me about the crocodiles that could be spotted among the mangroves.

I thought it would be great to look for crocodiles and go crabbing, but it was the wrong tide for it. Crocodile tours are done at low tide, the better to spot the crocs. Whereas high water is better for fishing and crabbing.

When you book a crabbing trip, they would have laid the cages overnight. On my trip, this yielded five crabs. We went to check the locations licensed to the tour operator (there are only so many crab pots that can be laid). After hauling up the catch, he released three because they were below size limits. Inspecting the remaining two, he released one, explaining to me that it was a female and those can’t be taken either.

This is why they still have crabs, people.

3. Overtourism in Cairns

When I arrived in Cairns, I was blown away by the sheer number of tourism-related businesses. I mean, as a Southeast Asian, I’ve seen worse. But, it is a lot, and I understood why my colleague in Brisbane disparaged Cairns as ‘touristy’.

The bulk of it is related to the Great Barrier Reef, but tourism in Cairns is also about the Wet Tropics rainforest and the Atherton Tablelands. On top of that, Cairns City also seemed overdeveloped. There seemed to be a lot of accommodations vacant and open for rental. Not all the business premises were occupied.

On the other hand, after spending three weeks there, I think it’s not very fair to say Cairns is over-touristed. The reason is because Cairns itself is not the tourist destination. It’s just the hub for the actual tourist destinations, which are around it. Aside from the near reef zones, which really do seem heavily touristed, the mid-zone and outer reefs are not crowded at all. This is down to how large the Great Barrier Reef is. Even just the Far North Queensland part is huge; you can divide it up between the tour operators. Which they do.

In any case, remember that you can also explore the Great Barrier Reef from numerous cities down the Queensland coastline. This way, you can spread the tourism footprint a bit more, and alleviate the stress on the reef (which is highest in the warmer north).

4. Eye on the Reef app

If you’re going to Cairns, or anywhere on the Great Barrier Reef, you can download the Eye on the Reef app. This app gives a map of the reef according to its usage zones, and you can submit your marine life sightings to help the Marine Park Authority monitor the health of the park.

Carbon offsetting information to Cairns, Australia

A return flight between Kuala Lumpur and Cairns via Singapore produces carbon emissions of approximately 4,383 lbs CO2e. It costs about $22 to offset this. 


Pin image for a blog article on reef safe sunscreen and sustainable travel tips for Cairns, Australia.

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