In 2020, the world’s largest reef, the Great Barrier Reef in Australia, experienced its third mass bleaching event in the last five years (Nelson, 2020). Exacerbated by climate change, extreme heat waves bleach coral as their thermal tolerance and photosynthetic symbionts are exceeded (Hoegh-Guldberg, 1999). While bleaching does not always lead to organism death, it reduces growth rates and increases the chance of mortality. As coral reefs are considered the rainforests of the ocean due to their immense biodiversity, it is crucial that we protect them (McIntyre, 2010). To do so, geoengineers are working on a temporary solution by brightening clouds to act as a ‘atmospheric sunscreen’.
Many researchers throughout the world are modelling the effects of brightening clouds on the temperature of the water below them. As brighter, whiter, clouds reflect more sunlight, they can prevent extreme heat waves from impacting the marine temperature (Figure 1) (Nelson, 2020). Instead of making new clouds, they work to brighten the existing clouds that lie low in the atmosphere above the reefs. Cloud brightness is determined by the number of droplets which form the cloud condensation nuclei (Latham et al., 2014). The number of droplets is determined by the number of particles (known as seeds) in the air, as every droplet in a cloud requires a tiny particle floating around it in order to condense. Thus, these machines spray seawater upwards as tiny droplets to allow for water evaporation. Then, the miniscule salt crystals leftover float into the air. By evaporating seawater into these salt crystals, additional cloud droplets are formed which enhance the cloud droplet concentration and thus its brightness and albedo (Latham et al., 2014).
While the process may be theoretically simple, the execution is logistically very difficult. Dr. Daniel Harrison, an oceanographer at the Southern Cross University in Australia, along with his team have become the first to test the methods out in the field (Figure 2) (Nelson, 2020). While their experiment was successful, it was only 1/10th of the scale necessary to make a real difference on cloud brightness. To make a large-scale difference, it is estimated that it would require 800 seawater spraying stations (Nelson, 2020). While they have tested them on ships, this contributes to emissions, which furthers the environmental impact of the project. Some proposed solutions include dedicated barges for the technology in the summer or placing the sprayers on existing boats that travel in the area.
Nevertheless, brighter clouds are a temporary solution. They require a lot of costly infrastructure, and therefore can only be implemented in the direst of circumstances. While this possible solution is celebrated by many, it is important to note that while cloud brightening may help delay coral bleaching, if emissions continue to rise it will not be able to keep the water cool enough forever. We must therefore tackle climate change itself by initiating collaboration between scientists, policymakers, and individuals to foster systemic changes in how we interact with the environment.
References
CBC, 2021. Cloud-based sunscreen could help protect the Great Barrier Reef from future heat damage | CBC Radio. [online] CBC. Available at: <https://www.cbc.ca/radio/quirks/oct-9-nobel-prize-winners-in-physics-and-chemistry-a-super-hot-planet-with-calcium-wind-and-more-1.6203540/cloud-based-sunscreen-could-help-protect-the-great-barrier-reef-from-future-heat-damage-1.6203554> [Accessed 26 Nov. 2021].
Hoegh-Guldberg, O., 1999. Climate change, coral bleaching and the future of the world’s coral reefs. Marine and Freshwater Research, 50(8), pp.839–866. https://doi.org/10.1071/mf99078.
Latham, J., Gadian, A., Fournier, J., Parkes, B., Wadhams, P. and Chen, J., 2014. Marine cloud brightening: regional applications. Philosophical Transactions: Mathematical, Physical and Engineering Sciences, 372(2031), pp.1–11.
McIntyre, A., 2010. Life in the World’s Oceans: Diversity, Distribution, and Abundance. John Wiley & Sons.
Nelson, J., 2020. Scientists trial world-first ‘cloud brightening’ technique to protect corals – Southern Cross University. [online] Available at: <https://www.scu.edu.au/engage/news/latest-news/2020/scientists-trial-world-first-cloud-brightening-technique-to-protect-corals.php> [Accessed 26 Nov. 2021].
Scientists push for combating global warming with cloud brightening. 2012. News Direct. Available at: <https://www.youtube.com/watch?v=cgJyw2cTrW4> [Accessed 26 Nov. 2021].
Comments
9 Responses to “SPF 1000?”
Hi iSci!
As I would love to see the Great Barrier Reef one day, I found this topic really interesting as scientists are becoming very innovative to tackle the effects of climate change. I am interested in climate science and policy, as I find it is inherently interdisciplinary; geoengineers, chemists, and biologists all are working together to develop solutions such as atmospheric sunscreen. Thank you for taking the time to read my post, please let me know any suggestions!
– Teagan
Hi Teagan,
I really liked the topic of your post and how you presented it. It’s also on my bucket list to scuba dive on the Great Barrier Reef one day so I really hope this solution (even though it’s temporary) can be implemented at full strength.
I have a few suggestions you may want to consider:
– In your second paragraph, I would change the flow of ideas from “What, How, Why” to “What, Why, How” (as in the order you present the components in the paragraph) by changing the order/structure of your sentences. “Throughout the world … atmosphere above the reefs” is a fantastic “What”. For the “Why” section you can start with “cloud brightness … cloud condensation nuclei. The number … the air because every droplet … tiny particle to condense around.” Finally, you can take the sentence “[To increase the number of seeds, the researchers] take the seawater … float into the air” and put it right before your last sentence to serve as the “How” section. Structuring the paragraph this way gives context to the “How” section and gets rid of some awkward transitions like “the idea behind this stems from the fact that”
– If there is a figure showing cloud droplet condensation around a seed I think including it would help the reader form a better picture of the whole process. (I also had no idea that cloud droplets needed seeds to form, I thought they were just water droplets!)
– Your final sentence seems to end rather abruptly and it kind of cuts off the message I think you are trying to get across. You may want to add on something like: “and individuals [to foster systemic changes in how we interact with the environment].” Adding something more to the end will really drive home your message about temporary vs lasting solutions.
I hope you find these suggestions helpful, and happy editing.
Matthew
Hi Matthew,
Thank you very much for your detailed feedback! I have taken another look at my second paragraph and tried to improve the flow. I really like your idea about my last paragraph, and have implemented your suggestion. With regard to the figure, I agree that a figure may be useful, however unfortunately all those that I found seem to include mostly verbal explanations with background images that don’t really add value.
Thanks again,
Teagan
Hi Teagan!
Your blog post is well-written and researched, and I think your topic is pertinent! We’re seeing more extreme weather patterns as climate change gets worse, and sometimes we forget that there are extreme changes occurring out of sight! There are a few things I thought your post could benefit from when you edit it!
1. I think moving Figure 1 above the second paragraph might be easier for the reader to navigate. As I was reading your post, I kept finding myself scrolling down to look at the picture and back up for the explanation! It’s a great figure, but moving it slightly would increase the readability of your post.
2. The research being done at Southern Cross University in Australia is incredible! I like that you included the methods they have been testing out! Consider including “(Figure 2)” at the end of your fourth sentence in your third paragraph as Figure 2 represents the water sprayers.
3. At the beginning of your post you talk about coral bleaching events. Consider looping back to this idea at the end of your post. Is the method Dr. Harrison is using affecting the rates of those bleaching events? How long will it take before we see those changes (whether on the micro or macro scale)?
Overall, I loved your post. I enjoyed learning about new research in this field this evening! Best of luck on the editing process!
Best,
Aoife H
Hi Aoife,
Thank you so much for your suggestions! I am going to move my figure 2 in-text reference like you suggested, however think I am going to leave figure 1 below the second paragraph. I have heard that you are supposed to have the figure after you speak about it. While I think it would be great to loop back to the coral bleaching, upon looking into it there has not been much research on the overall effects as this was a preliminary study.
Regards,
Teagan
Hey Teagan,
This was a really great post! I loved how you integrated a large array of topics and ideas from biological with the ecosystem destruction, to chemical and geoengineering with the potential solutions for coral bleaching. You had a great flow to the piece, and it was really well written and informative. Great Work! Here are a few ideas to consider as you begin the editing process:
1) I think you can remove the comma after ocean (“rainforests of the ocean…”) in the second last sentence of your first paragraph.
2) Do you mean that “geoengineers are working ON a temporary solution”? Consider revising.
3) This may be personal preference, but I think you can remove the transitionary “Throughout the world” leading into paragraph 2, or if you want to keep the idea say “Many researchers globally…”
4) Ironically, I think you could use a transitionary “Nevertheless” or “However” at the start of your final paragraph as you are transitioning from solutions of how to use/continue the brightening to how it cannot continue forever.
Overall great work! I loved how you ended the post with a call-to-action of sorts too! Great work and I cannot wait to read your final draft. Happy editing!
-Sarah
Hello Sarah,
Thank you for your great ideas and feedback! I have corrected the mistakes with regard to the comma and the word “ON”. I have also changed my transition words to those you suggested.
I appreciate you taking the time to comment.
Best,
Teagan
Hi Teagan,
Really interesting blog post! I had the great gift of scuba diving in the Great Barrier Reef march break of 2020 just before our world was strongly hit by COVID, and it was magical!! I really hope it continues to survive and can thrive with the conditions we alter.
Here are a few suggestions:
– Should there be an apostrophe here? “In 2020, the worlds largest reef” change to “In 2020, the world’s largest reef”
– I feel your explanation of the cloud brightening could be a little clearer. Try changing it to this: “Instead of making new clouds, they work to brighten the existing clouds that lie low in the atmosphere above the reefs. Cloud brightness is determined by the number of droplets which form the cloud condensation nuclei (Latham et al., 2014). The number of droplets is determined by the number of particles, known as seeds, in the air, as every droplet in a cloud requires a tiny particle floating around it to condense around. Thus, these machines spray seawater upwards as tiny droplets to allow for water evaporation. Then, the miniscule salt crystals leftover float into the air. Therefore, by evaporating seawater into salt crystals, additional cloud droplets are formed, which enhance the cloud droplet concentration and thus its brightness and albedo (Latham et al., 2014).
– In the paragraph above, many add one sentence about what a high/low albedo means with reflection/absorption of light. I know it was in RP1 but it would still be nice to have a definition and see how this property applies to the clouds.
– I think it would be nice to have a greater “although” moment in your conclusion here, “While this possible solution is celebrated by many, it is important to note that while cloud brightening may help delay coral bleaching, if emissions continue to rise it will not be able to keep the water cool enough forever. Tackling climate change and its impacts will require immense collaboration from scientists, policymakers, and individuals.” maybe change to “While this possible solution is celebrated by many, it is important to note that while cloud brightening may help delay coral bleaching, if emissions continue to rise it will not be able to keep the water cool enough forever. We must therefore tackle climate change itself and its impacts require immense collaboration from scientists, policymakers, and individuals.”
Overall terrific work!
– Clara
Hi Clara,
Thank you so much for your suggestions. I appreciate you taking the time to reword some of my phrasings. I added the apostrophe in the first sentence and applied your changes to my second and fourth paragraphs. With regard to albedo, unfortunately, I had to omit my description as I do not have enough word count and I believe the cloud droplet formation explanation is more novel to the audience.
Once again, thank you for taking the time to provide such valuable feedback.
Regards,
Teagan