The Hidden Climate Impact of Hydrogen Leaks: Hydrogen's Potential as a Greenhouse Gas
By Cora Scott
Background
Hydrogen gas has been an increasingly popular energy source meant to serve as an alternative to currently widely used energy sources, particularly fossil fuels. Unlike coal, oil, and natural gas, hydrogen can be used to generate electricity through fuel cells, producing water as a primary byproduct rather than carbon dioxide. Hydrogen has particularly been investigated as a replacement energy source for methods of heavy transportation (aviation and shipping), steel and chemical manufacturing, long-term energy storage, and certain industrial heating applications. Despite this process producing less toxic byproducts, the problem with hydrogen as an energy source is that its merely an energy carrier, not a primary source, meaning that it must first be produced utilizing another energy source. For instance, green hydrogen is produced through water electrolysis via renewable energy (solar or wind power), blue hydrogen is produced through methane steam reformation and carbon capturing, and grey hydrogen is also produced from natural gases but without the process of capturing carbon dioxide. Though it inherently reduces CO2 emissions and produces less toxic byproducts, research has shown that leakage during the production and transportation could enhance global warming by allowing the radical gas to react with already present greenhouse gases, such as methane and hydroxyl radicals. This can lead to a perpetuation of these pollutants in our atmosphere, worsening the climate effect these greenhouse gases can have.
Journal Article
A research study conducted in 2025 by Ouyang et al. investigated the global hydrogen budget, accounting for the processes that release hydrogen into the atmosphere and the processes that remove it. They investigated the hydrogen sources and sinks between 1990 and 2020, but particularly the time between 2010 and 2020, compiling multiple data sets, atmospheric observations, emission inventories, and mathematical models and using a bottom-up approach to estimate the global production and removal processes of this gas. This included the production of H2 through methane oxidation and biological nitrogen fixation, gas being released via fossil fuel and biofuel combustion, leakage from its production and transportation, and removal processes such as atmospheric reactions with hydroxyl radicals and soil microorganisms. This study utilized an earth system model of how the changes in atmospheric H2 concentrations influenced global surface temperatures.
Fig. 1: Summarized sources and sinks of hydrogen gas in the atmosphere.
The study found that the concentrations of H2 have increased across the globe, concluding that the average surface concentrations increased from roughly 523.4 ppb in 1992 to 543.5 ppb in 2020, showing an increase in H2 by roughly 3.8%. They also estimated that the average global hydrogen sources during 2010-2020 were 69.9 Tg/year and the global hydrogen sinks were 68.4 Tg/year. They concluded that much of this increase could be traced back to human activity and industrialization, with the largest production factor being the intentional photochemical production of the gas, contributing to about 56% of the source, but the other 44% came from additional sources. Furthermore, they found that the primary H2 removal process was soil uptake via microorganisms, containing enzymes called hydrogenases, contributing to ~73% of the global H2 removal. They also found that between 2010 and 2020, the hydrogen leakage from industrial processes and storage was 0.7 +/- 0.4 Tg. Though this is small, the study concluded that transitions to using hydrogen energy more could dramatically expand this problem and noted that hydrogen leakage remains poorly constrained due to relatively few direct measurements, worsening this issue. They also concluded that this increase in H2 in our atmosphere has increased the global air surface temperature by 0.020 +/- 0.006 ℃, modeling under different conditions and socioeconomic scenarios. This study analyzed the natural and man-made impacts of H2 concentrations and showed that this directly contributes to global warming. However, they do not state that the potential of hydrogen as an energy source should be abandoned, but instead state that understanding hydrogen emission control is necessary to prevent and negate further harm to our environment.
Fig. 2: The spatial sources (top) and sinks (bottom) of hydrogen gas across the globe.
News Article
The CarbonBrief article by Ayesha Tandon does a relatively good job summarizing the findings of the study by Ouyang et al. (2025). In particular, the article accurately describes the atmospheric chemistry involved in higher H2 concentrations, explaining it in a way that’s quite digestible for less knowledgeable audiences. Tandon thoroughly discusses the interactions between hydrogen gas and hydroxyl radicals in the environment, explaining that this directly correlates to longer lifetimes for methane–a destructive greenhouse gas–as the radicals are less available to break down methane as they choose to break down H2 instead. Tandon also makes sure to directly include data from the study, particularly regarding how this increase in methane’s atmospheric perpetuation directly leads to global warming. Furthermore, Tandon analyzes the impacts of largely switching to hydrogen gas as an alternative energy source, touching on some of the main conclusions of the study as well as demonstrating some of the hesitation scientists have regarding the wide use of H2.
However, this article could have done a better job touching on the limitations and uncertainties present in the research. For example, Tandon does not extensively discuss the uncertainties associated with estimating hydrogen uptake by soil microorganisms, which Ouyang et al. (2025) identified as one of the largest sources of uncertainty in the global hydrogen budget. Additionally, the headline may lead readers to overestimate the magnitude of hydrogen's warming contribution, since the study estimated a relatively small temperature increase of approximately 0.02°C. The article could also more clearly distinguish between hydrogen produced through natural atmospheric processes and hydrogen released through industrial production and leakage.
Overall, I’d rate this article as an 8/10 because it successfully communicates the main findings of the study while making the information understandable and relevant to the general public. Although some scientific limitations could have been discussed in greater detail, the article provides a digestible overview of the environmental chemistry involved in these energy processes and the associated implications for climate change.
References
Ouyang, Z.; Jackson, R.B.; Saunois, M.; Canadell, J.G.; Zhao, Y.; Morfopoulos, C.; Krummel, P.B.; Patra, P.K.; Peters, G.P.; Dennison, F.; et al. The global hydrogen budget. Nature 2025, 648, 616–624. DOI: 10.1038/s41586-025-09806-1.
Tandon, A. Hydrogen emissions are ‘supercharging’ the warming impact of methane. CarbonBrief [Online], December 17, 2025. https://www.carbonbrief.org/hydrogen-emissions-are-supercharging-the-warming-impact-of-methane? (Accessed October 24, 2026).
I thought it was interesting that hydrogen can still contribute to global warming even though it is considered a cleaner energy source. I also didn't realize that hydrogen leaks could affect how long methane stays in the atmosphere. It makes me wonder how much of an impact this could have as more industries start using hydrogen. Do you think companies should be required to have stricter leak detection systems before switching to hydrogen as an energy source?
ReplyDeleteHi Bryanna, I think this is a wonderful question! Rob B. Jackson from Stanford, one of the authors on the journal article, puts this in a really good way actually. He summarizes a lot of the information the study concluded, including that Hydrogen is a great source of energy to replace fossil fuels, but if used on a large--or even global--scale, the chances of leakage would be very high. He attributes this in particular to the size of H2, stating that we could expect very large leakage since there is already a leakage problem for methane (which is larger). I think that since hydrogen gas is a very small molecule that perpetuates methane lifetimes (which also contribute positively to hydrogen concentrations), further studies of large-case hydrogen energy and leakage prevention would be necessary. I do think this would likely lead to necessary legislation or restrictions regarding its use/management.
DeleteHey Cora, I love that you touched on a source of energy that could be used as a cleaner energy source. Unfortunately, even the sources that seem cleaner can have their downsides. I am wondering if there are studies being done to target those leaks and how they could potentially be lessened overall. As you mentioned with the uncertainties of hydrogen uptake by microorganisms, do you believe that we would be able to utilize organisms such as plants or other flora to be able to combat these hydrogen leaks or do they require solely man-made solutions?
ReplyDeleteHi Anika, I actually really appreciate this question as it was one of the aspects of this study I found to be the most interesting! The journal article actually touches on the need for further study regarding this soil and microorganism uptake of hydrogen. Ouyang et al. really outlines that much of the research regarding this has many different errors associated with it, and so one of the biggest struggles regarding this topic is limiting those errors to get truly reliable data. I do think that this shows a lot of promise though, and I've seen some other studies outside of this one investigating similar topics!
DeleteThis was a very informative post. These articles illustrate that reducing carbon footprint does not always directly minimize greenhouse effect. The relation between the two, with respect to hydrogen emissions, is complex in that hydrogen will extend methane half-life, yet methane is second place to CO2 for contribution towards global warming. I had thought that the primary carbon footprint of hydrogen was concentrating it and compressing it into a liquid. Do you think that hydrogen will catch on as an alternative energy source for consumer use, or will it remain a niche business tied to the success of fossil gas?
ReplyDeleteHello Alex! I think there's a lot of nuance to your question that I really appreciate. It's hard to know how much this type of energy could catch on as the fossil fuel industry maintains quite a tight grip on our energy economy, which was something previous blogposts touched on! The news article points out many quotes from Professor R. B. Jackson, one of the authors of the journal article, of which he touches on this question. He believes that hydrogen energy would be a really good replacement to fossil fuels, but he does note that the leakage potentials are alarming. He does note though that much of this increase in leakage is actually likely due to energy from coal and natural gases, so if we were to replace these fossil fuels with hydrogen energy, there may be some hope regarding this. Ultimately, I think that as we continue to reach a point where the climate can't handle much more of our current practices and fossil fuels continue to run out, many countries will likely have to turn to sources like hydrogen gas but further research may be necessary to get the ball rolling.
DeleteLiked the post, and the topic of choice is very interesting. I thought it was quite interesting that even 'clean' energy sources/carriers aren't as clean as we may think they are. It's also quite interesting that hydrogen protons and hydrogen radicals are both produced in hydrogen production methods, do you think that there are any ways to limit the production of H radicals and selectively produce the preferred form of hydrogen?
ReplyDeleteHello Carson, this is such an interesting question and I really like where you're going with this! In the conventional hydrogen production methods necessary to provide the hydrogen for this energy process, such as electrolysis, the protons actually act as intermediates that are reduced to form the hydrogen gas. The hydrogen radicals are then actually produced when the hydrogen gas makes its way into the atmosphere, interacting with hydroxyl radicals, which then leads to this hydrogen radical formation with water as a byproduct. Since these hydroxyl radicals present in the atmosphere are necessary for the breakdown of methane, the ability for the hydrogen gas to compete with methane for interactions with these radicals inherently leads to larger concentrations of methane in the atmosphere. I think then that the important intervention here would actually be to find a way to capture this hydrogen gas so that it can't reach the hydroxyl radicals, or it would be to find a way to chemically modify the hydrogen gas so that it's less competitive.
DeleteThis is a very interesting topic. It really highlights the fact that there are always good and bad attributes to each energy source and you must think of it holistically. I found it incredibly interesting how the lifetime of methane is affected, and how the hydroxyl radicals react with H2, and then consequently do not break down methane. Understanding and controlling hydrogen emissions will be important while we continue exploring it as an alternative energy source, especially given the uncertainties surrounding current leakage measurements. I would be interested to learn more about where most hydrogen leakage occurs and what technologies or strategies could be used to prevent it. One would think if we could identify the sources/impacts a little more there would be more regulations in place. Are there steps being taken to do this?
ReplyDeleteThe topic of hydrogen leaks was a very interesting read, because it underlines the common theme we see in class of the anthropogenic affects of emissions into our atmosphere having large global warming potential. I am wondering your thoughts on "water splitting"/hydrolysis and if you believe these harmful residuals can be tackled by an increase in hydrogenase-containing microbes (like cultivating large-scale colonies of these bacteria) for example?
DeleteHi Olivia, thank you so much for your question! I agree that understanding where this leakage is occurring and taking the steps to prevent it would be of utmost priority if we want to make hydrogen energy an effective replacement for fossil fuels without further contributing to global warming. It seems that the articles implied that the two main sources of hydrogen gas in the atmosphere were leaks and methane oxidation. The leakage seems to largely be due to transport and storage, and the authors for both articles state that further investigation into how to prevent this is necessary. They note that the smaller size of the gas exacerbates this problem, so I would assume that much further experimentation and instrumentation development would be necessary to mitigate this.
DeleteHello Megan, I love this question so much! I actually thought this was one of the most interesting parts of the article, and kind of like what I said when responding to Anika, the journal article touches on this a lot. Ouyang et al. did some slight studying with microbes ability to "eat" the hydrogen, and found that much of the hydrogen in the atmosphere is actually consumed this way. However, they did conclude there to many experimental errors and unknowns within their study, and found that it's hard to know the true potential of this method without reducing those. It seems that this is a very promising avenue, but further experimentation is necessary to truly understand its potential.
DeleteHi Cora. I thought your post was very interesting, and I have never heard of hydrogen energy before. I think it is very interesting on how hydrogen is a resource that we have been using, but we don't know much about regulating it, like the leaking you mentioned. I feel like that just goes to show the positives and negatives correlated with each new energy source we try to utilize. I also like how you mentioned that hydrogen is a byproduct created from something else so it is still causing global warming effects overall. I know you mentioned that the main absorption was from soil, does that effect microorganisms or agriculture negatively? Additionally, do you think the positive effects of hydrogen energy outweigh the negatives?
ReplyDeleteHi Tia, I'm glad to hear that you felt like you learned a lot from this blogpost! As far as my understanding goes, since much of the soil and microbes that are up taking this hydrogen contain hydrogenases--enzymes that have natural affinities for this gas--this uptake doesn't harm them. I'm not sure though if that would change if there were to be too much hydrogen in the atmosphere, if that could cause something similar to poisoning. This would be something that I think should be investigated when looking into the different impacts of widespread use of hydrogen gas for energy and is a wonderful point to have brought up! As far as if the positives outweigh the negatives, the articles also touch on this. Ouyang et al. actually concludes that since methane oxidation is one of the primary drivers of hydrogen formation in the atmosphere, if we were to reduce fossil fuel burning, it could result in low enough hydrogen levels--particularly in certain areas--leading to more positives than negatives. I would say that exploring hydrogen gas as a widespread energy source appears to be worth the investment and time.
DeleteReally interesting post! I hadn't considered that hydrogen leakage could indirectly contribute to global warming by reducing the availability of hydroxyl radicals to break down methane. I also thought your point about the uncertainty surrounding hydrogen uptake by soil microorganisms was interesting, especially since it accounts for such a large proportion of hydrogen removal. Do you think these uncertainties should discourage the widespread adoption of hydrogen energy, or should the focus instead be on developing better methods to detect and prevent leakage?
ReplyDeleteHello Madison, I really appreciate your question! It seemed to me that despite many of the uncertainties around utilizing soil and microbial breakdown of hydrogen gas, utilizing it as a main energy source would be worth the investment. I think this is because the authors note that much of the formation of hydrogen gas in the atmosphere is actually due to the oxidation of methane, so if we were to adopt hydrogen gas as a main energy source, this perpetuation of this cycle between methane and hydrogen would decrease astronomically. Furthermore, if we could find ways to prevent leakage and adopt microbial breakdowns on massive scales, we could further prevent hydrogen gas from contributing to global warming.
DeleteHi Cora, your explanation of the different hydrogen production methods made me wonder about how we compare their overall climate impacts. Even if green and blue hydrogen had the same leakage rate, their production processes could lead to different total emissions. It would be interesting to compare them across the entire life cycle, including the energy used for production, storage, and transportation. Do you think focusing on these differences would help identify which applications of hydrogen offer the greatest climate benefits?
ReplyDeleteHi Siyi, I completely agree that comparing the life-cycle emissions of different hydrogen production methods would be really valuable. Even if both production methods had identical hydrogen leakage rates, their overall climate impacts could differ because of the emissions associated with their generation, extraction, methane leakage, and the effectiveness of carbon capture. Since storing and transporting hydrogen gas requires additional energy and infrastructure, understanding the entirety of the life cycle is incredibly important to fully understand its impacts. I think that understanding the realities of renewable energy capabilities for different geographical locations and industries would vary how realistic hydrogen energy could be. I think understanding these nuances and variations would definitely be necessary to fully understand where hydrogen energy can provide the furthest benefit.
DeleteHi Cora this was such an interesting post! I thought it was really interesting how hydrogen, despite being considered a cleaner alternative to fossil fuels, can indirectly contribute to global warming by competing with methane for OH radicals. And that soil microorganisms account for such a large portion of atmospheric hydrogen removal. Since soil uptake is one of the biggest uncertainties in the study, I wonder how changes in soil conditions due to climate change could affect hydrogen removal in the future. Could this potentially create a positive feedback loop where warming reduces hydrogen uptake, allowing more hydrogen to accumulate and further extend methane's atmospheric lifetime?
ReplyDeleteHello Jasmine, I love this question so much! The journal article doesn't touch on this topic directly, but it does mention some of the characteristics that contribute to hydrogen uptake by soil and microorganisms. Some of these were the soil moisture, temperature, porosity/texture, and snow cover. They also identify many uncertainties regarding their measurements of these and understanding their impacts. I think that since we know climate change can lead to cases of extreme drought and temperature abnormalities, we can assume that inhibition of this process would be possible. I think further investigation into this topic would certainly be necessary because it could definitely create a positive feedback loop that could perpetuate hydrogen's impact on global warming exponentially.
DeleteHi Cora! Do you think there are viable methods currently available for quantifying hydrogen uptake by microorganisms? I think this is a really interesting article and can help bridge a gap to readers since hydrogen is a well known element just as existing broadly. I also think those visuals are incredibly interesting since they do illustrate that the H2 concentrations are not necessarily less in some places than others but rather there can be sinks where the hydrogen is going.
ReplyDeleteHi Samantha, thank you for your question! The study actually touches on this topic quite heavily, indicating that scientists currently can measure hydrogen consumption in individual soil samples and controlled laboratory environments, but extrapolating those measurements to global hydrogen uptake is much more difficult. Like I mentioned before in some previous comments, the study notes many different uncertainties regarding these studies, noting how hard it is to fully examine this issue. It seems like there are ways to directly measure this hydrogen uptake, but not currently any available methods that can viably analyze these findings on a massive scale. Further research, and likely instrumentation/software development, would likely be critical in being able to fully understand this topic and its involvement in hydrogen energy use because understanding where atmospheric hydrogen is being removed is just as important as understanding where it is being emitted. Improving our ability to measure these natural sinks will be essential for predicting how increasing hydrogen emissions could influence our atmospheric chemistry and future climate change.
DeleteHi Cora, does the article go into the differences between blue, green, and gray hydrogen in terms of impact on the environment through carbon emissions, cost, and leakage? Is there a certain method that would be easiest to make "leak-free" or implement on a massive scale? Thank you for posting! :)
ReplyDeleteHi Rain, thanks for your comment! The article gives basic definitions of the differences between blue/green/grey hydrogen and discusses that since blue hydrogen comes from renewable energy, it would have better long-term effects, but it doesn't discuss their relation to carbon emissions/cost/leakage in great detail. This is a good point, and I think it definitely could've strengthened the news article's analysis of the study! There also was no "one-way" method presented to solve the leaking of massive-scale problems related to hydrogen energy, but instead the study discussed the need for further research before that could be understood.
DeleteHi Cora! I really enjoyed reading your post, especially the discussion of how hydrogen can indirectly contribute to global warming despite being considered a cleaner energy alternative. I thought it was particularly interesting that soil microorganisms account for approximately 73% of atmospheric hydrogen removal, yet there are still significant uncertainties in estimating how effective this process is globally. It makes me wonder how changes in soil conditions, such as moisture and temperature, could affect the ability of these microorganisms to remove hydrogen as climate change progresses. Could changes in these natural hydrogen sinks potentially make it more difficult to control atmospheric hydrogen concentrations as hydrogen energy becomes more widely used?
ReplyDeleteThis was a very insightful look into how something as innocuous and seemingly clean as hydrogen can nevertheless have detrimental climate impacts. Your explanation of how hydrogen interacts with hydroxyl radicals was especially interesting because it highlights how an energy source that produces fewer direct emissions can still have indirect effects on climate change. Since hydrogen leaking was established as a global warming contributor, I'm curious if you think improvements in storage and transportation infrastructure would be enough to make hydrogen a sustainable energy source
ReplyDelete