Refreezing poles to help reverse climate crisis is possible, scientists claim
Independent article (via Yahoo news)
Environmental Research Communications article
This scientific article is a bit different than some of the others we've talked about thus far, as it presents a plan rather than a finding. The authors open by emphasizing the dire threat global warming poses to the Arctic, warming at nearly twice the global average due to a combination of decreased albedo, increased cloud cover, increased energy transport from lower latitudes, and a rise in black carbon and soot aerosols which absorb heat. However most aerosols are believed to have a net cooling effect due to their reflective and scattering properties (although its extent is not yet fully understood). To increase the reflectivity of the atmosphere, the authors propose stratospheric aerosol injection (SAI) as a supplemental method to combat climate change. Specifically, they aim to inject sulfate aerosol into the polar and subpolar regions.
In Reflecting sunlight: Recommendations for solar geoengineering research and research governance; The National Academies Press: Washington, DC, 2021.
The ERC article cites a couple studies that modelled SAI deployment in the Arctic and at the equator, including a 2021 model which indicated that a springtime injection would reduce Arctic temperatures by nearly 50% more than a year-round injection. A drawback is noted: Arctic deployment of SAI may move the Inter-Tropical Convergence Zone (ITCZ) southwards, affecting precipitation patterns. This is a motivating factor in following up any Arctic injection with an Anarctic one, therefore minimizing shift in the ITCZ. They plan to deploy SO2 gas at an altitude of 13 km and target latitudes of 60°N and 60°S, delimiting zones including all of Greenland and Antarctica. The annual sulfur mass deployed would be 13.4 Tg SO2. The article spends a lot of time comparing and contrasting different aircraft and their potential costs, with plan rounding out to ~$11 billion USD annually.
The study is calibrated to reduce the year-round average Arctic surface temperatures by 2°C. The authors do note that some of the aerosols would flow towards the equator, so the cooling would be detectable throughout the Northern Hemisphere, and likely the high latitudes of the Southern Hemisphere. They do recognize that an increase in aerosol concentrations may also lead to an increase in heterogeneous reactions leading to halogen activations, but breeze over it since the aerosol would be present during the summer. They also bring up the potential worsening of the ozone hole as a result of injecting ozone-depleting aerosols into the stratosphere, but say that more research is needed to evaluate it. The deployment would emit the equivalent of 12-25 millions of metric tons of CO2 into the atmosphere, in addition to contrail formation and the release of NOx.
They conclude the ERC article by saying it has not been established whether the SAI project would have a net positive effect on the world, but it would be logistically feasible (with substantial international cooperation) to cool the polar and subpolar regions.
The Independent article, written by Maryam Zakir-Hussain, provides a one-sided but mostly accurate overview of the concept of SAI. The article is clearly written for an audience that understands and accepts global warming as a climate crisis, draws readers in with the concept of refreezing the poles, and sprinkles in a classic "polar bear on a melting ice cap" photo. Zakir-Hussain states that aerosol particles "could reverse ice loss by partially blocking sunlight", which while not scientifically inaccurate certainly lacks nuance. At this point it would have been helpful to contrast greenhouse gases with aerosols and differentiate their climatic effects. The article then goes on to emphasize the large carbon footprint of the study, emphasizing that this only treats a symptom of the climate crisis, and should be used to buy us time for further mitigation.
I appreciate that Zakar-Hussain pulled quotations from scientists concerning the study, but she only included assenting views. The main reason cited for the plan's controversy is the greenhouse gas emissions from the aircraft fleet, but this is one of many problems. The Independent article doesn't mention the ozone depletion or halogen activation effects touched on in the ERC article. There is no discussion of human health effects, even though particulate matter has been linked to cardiovascular and respiratory disease. Additionally, if acidic sulfate particles spread out all over the globe, an increase acid rain seems like an inevitability. Any one of these points (or plenty of others) could have been expounded upon, but Zakar-Hussain focuses on the need for immediate action urged by like-minded scientists that she quotes.
I rate the Independent article 7/10 for providing a mostly accurate summary of the scientific article, with points taken off for a too-brief discussion of drawbacks and a lack of citation of scientists with opposing viewpoints, even though the idea is presented as controversial. However, my main gripes are with the ERC plan itself, whose authors seem to have taken a brazenly brief look at the literature in the sulfated aerosol field and write off many potential negative climatic impacts with a shrug of their shoulders.
I really enjoyed reading this series of articles because it offers a different point of comparison than what we have done in class thus far! In the Environ. Res. Commun. article the authors identified that there was a number of logistical challenges outside of the scope of their paper (e.g. inter-governmental coordination and agreement, funding sources, etc…). However, they did not identify a lot of these other challenges or provide any discussion on them. I am curious if in your research for this blog post or if you have thought of what some challenges other than what the authors identified in their paper could be for SAI strategies. Likewise, are there any solutions that could be undertaken. One challenge that jumped out to me right away is how to find common ground among different governing bodies to support this endeavor that would impact everyone.
ReplyDeleteYou're absolutely right about the logistical challenges in implementation. Although there may only be 12 countries whose airspace are involved in the plan, I found that many are worried about the lasting effects of SAI. Many scientists have called for research governance, as small field tests could still release a significant amount of sulfur into the atmosphere. A related worry is unauthorized covert deployment, which while incredibly costly is possible due to lack of restrictions. The prospect of large-scale SAI also feeds into weaponization concerns, particularly for weather modification in a military context. Interestingly enough, these fears have been around for decades, as the Environment Modification Convention (ENMOD) was drawn up in the late 1970s. It prohibits any environmental or geophysical modification to be used as a weapon of war and has the signatures of 78 states around the globe. Obviously, this wouldn't necessarily stop a hostile state, but proponents of SAI argue that the technique is not targeted enough to be effective for war.
DeleteSince the article is focused on the potential of increased reflectivity to lower global temperatures, could you elaborate on how a 'decreased albedo' is contributing to the increase? Google defines albedo as 'fraction of light that is reflected by a body or surface' but im not sure how that ties into it
ReplyDeleteAbsolutely! Albedo, i.e. surface reflectivity, is much higher for sea ice than water or land. This means that as the polar ice caps melt and the reflectivity decreases, the poles will absorb more heat, leading to accelerated warming. The SAI project aims to increase stratospheric reflectivity in part to combat this reflectivity loss due to sea ice melting at the earth's surface.
DeleteHi Cara,
ReplyDeleteI really enjoyed reading your write up. I have noticed that many relativity credible news sources such as the Guardian, Washington Post, or NYT have a very similar manner of presenting information pulled from scientific papers. For example, most all of the authors accurately present the findings of the paper yet tend to leave out detailed information about how the results were collected ultimately resulting in a lack of context for the readers. I also liked that the article you chose focused on a plan more so than a paper that summarizes the findings of a study - it essentially goes to show that regardless of how scientists present information, there is always a chance that the meaning could become slightly convoluted.
Hi Cara,
ReplyDeleteI found it interesting that the authors of the scientific article included a comment on how their suggested program was "easier sell to a skeptical world" than a global SAI deployment. I was struck by the rarity of appeals like this in the literature that I read. I think the inclusion of this comment in the Environmental Research Communications article points to the authors' understanding of the non-scientific community, and I appreciate their awareness that their proposed program may not be well-received by the general public. In climate change research specifically, do you feel there is a need for researchers to propose solutions that appeal to the general public?
That's an interesting point, Maddie.
DeleteIn general I think scientific research should remain to some degree insulated from public discourse. Public opinion need not bias scientific investigations too much. Nonetheless climate change researchers should consider feasibility, especially given the politicization of climate change in the US. In my opinion, the burden should fall more upon engineers and scientific policy makers than scientific researchers. There is still plenty of fundamental science to figure out, and researchers' time is best spent doing that. However, this ERC article made it very clear to me that communication between climate change researchers and engineers needs to be improved. To overcome the knowledge gap and take steps forward, both sides need to make an active effort to inform the other.
Great analysis Cara! One of the comments under the article reads "What could possibly go wrong??? Go for it." which I think really speaks to what you've pointed out about the lack of nuance when presenting SAI.
ReplyDeleteHi Cara, I appreciate the choice in articles! Very interesting, indeed. Their ideas and logistics could use some work, but I noticed in there that "the deployment would emit the equivalent of 12-25 millions of metric tons of CO2 into the atmosphere, in addition to contrail formation and the release of NOx." How do you think this would affect the atmosphere? In a positive or negative way?
ReplyDeleteI noticed the research article emphasizes the feasibility of a 'global cooling' plan such as this one, but neither the research article nor the Independent article do a very good job of analyzing the cost benefit analysis of a plan such as this one (because of the limited research on net positive impacts). I noticed in the comments of the Independent article there was a person bringing up chem trails--I'd assume other conspiracy theories such as this one would become popular if these articles were to reach a larger audience. Is it responsible for either the journalists or the researcher to publish such articles given the plan's questionable positive nature and the general public's tendency to sensationalize things?
ReplyDelete