The greenhouse effect occurs when atmospheric gases trap heat from the sun’s rays, warming the Earth and the lower atmosphere. The most well-known greenhouse gas, as well as the most abundant, is carbon dioxide (CO2), but non-CO2 greenhouse gases have global warming potential as well. While carbon dioxide accounts for 71.6% of anthropogenic greenhouse gas emissions (1), methane accounts for 20.7%, and N2O accounts for 6.9%. The potential contributions to the greenhouse effect of these gases are quantified in their global warming potential (GWP), usually reported in CO2 equivalents. Methane has a global warming potential of 26-28 CO2 equivalents over 100 years, or 84-87 equivalents over 20 years, due to its shorter lifetime, greater insulating effect, and potential to participate in ozone synthesis in the troposphere (2). Anthropogenic methane sources include industrial agriculture (mostly cattle farming), the fossil fuel industry, other industrial activities. While agriculture contributes the most to anthropogenic methane emissions according to the EPA (1), the fossil fuel industry is an important contributor as well.
An article entitled “Fossil Fuel Industry’s Methane Emissions Far Higher Than Thought” was published in The Guardian on October 5, 2016. The article references the compilation of the largest database of worldwide methane emissions, published in Nature on October 5, 2016 (3). It focused on the result that the methane emissions from the fossil fuel industry (after being adjusted for natural gas methane seepage) are 20-60% larger than previously inventories had suggested. The ‘extra’ methane emissions were compared to those from the Aliso Canyon gas leak (the largest in US history) and shown to be 300 times larger than the emissions from that event. Obviously, the fossil fuel industry’s methane emissions are emitted all over the world and on a much larger timescale than a single gas leak in a single location, so this comparison is not very useful past illustrating sheer volume of emissions.
The lead author of the Nature paper, Stefan Schwietzke, was quoted in the article. Schwietzke emphasized the importance of methane in attenuation of the anthropogenic greenhouse effect and climate forcing in his comments. He went on to say that the models on methane emissions were very sensitive to the data inputs, which is why this new model of worldwide methane emissions is so important. Also quoted was Dr. Grant Allen, from the University of Manchester, in a supposed Nature commentary (which was not linked), stating that climate prediction models need to be reassessed in light of the new data on anthropogenic methane emissions. The article briefly touched on the methodology used in the Nature paper, describing the examination of isotopic ‘fingerprints’ of methane sources over thousands of measurements.
The Nature article, “Upward revision of global fossil fuel methane emissions based on isotope database,” examined worldwide methane emissions by compiling thousands of measurements, and emphasized the increased estimation of methane emissions from the fossil fuel industry (3). It noted that fossil fuel methane emissions are not increasing over time, but are 60-100% larger than previously estimated. After accounting for natural gas methane seepage, the emissions from natural gas, oil, and coal production and their usage are 20-60% larger than estimates. The authors referenced the impact this might have on mitigation of anthropogenic climate forcing due to the fossil fuel industry. The authors used an atmospheric box-model to interpret their database of δ13Csource measurements, choosing their included data to give maximum constraints and therefore greater certainty in their predictions.
The Guardian article includes a figure titled “Emissions from the fossil fuel industry contribute 30 to 45% of atmospheric methane” (shown below), apparently sourced from the Nature paper, but did not include any links. The 60-100% increase over the previously estimated 15-22% range for fossil fuel methane emissions was used to create the figure, but this increase is not adjusted for natural gas methane leakage. The Guardian article references the adjusted range (20-60%) within the first paragraph, so it may be unclear to the reader that the numbers in the figure are from unadjusted estimates. The figure is helpful to demonstrate the fraction of methane emissions that come from the fossil fuel industry, compared to the other sources, but is simplistic and does not accurately portray the findings in the Nature paper.
Overall, I would give the Guardian article an 8 out of 10. It gave good background, quoted scientists involved with the project, and concisely pointed out the implications of their findings. The figure they included was not the best, but communicated more information than it missed due to inaccuracy in either calculation or description. They also did not mention that the fossil fuel industry is a large contributor to CO2 emissions as well, which already informs policy decisions about mitigation of greenhouse gas emissions. In their discussion of how curbing methane emissions would have beneficial effects on climate forcing sooner than CO2 regulations would, they did not mention the largest worldwide contributor to methane emissions, industrial agriculture. Other than that oversight of the (slightly) bigger picture, it was much better than many popular science articles published online.
- Summary Report: Global Anthropogenic Non-CO2 Greenhouse Gas Emissions: 1990 - 2030 (Rep. No. 430-S-12-002). (2012, December 01). Retrieved October 10, 2016, from https://www3.epa.gov/climatechange/Downloads/EPAactivities/Summary_Global_NonCO2_Projections_Dec2012.pdf
- Understanding Global Warming Potentials. (2016, August 09). Retrieved October 10, 2016, from https://www.epa.gov/ghgemissions/understanding-global-warming-potentials
- Schwietzke, S., Sherwood, O. A., Bruhwiler, L. M., Miller, J. B., Etiope, G., Dlugokencky, E. J., . . . Tans, P. P. (2016). Upward revision of global fossil fuel methane emissions based on isotope database. Nature, 538(7623), 88-91. doi:10.1038/nature19797
Great choice on The Guardian article. I thought that the author of The Guardian article stated key facts that are important for the reader to understand from the Nature paper, however some key facts were left out. For example, I think it is important for the reader to understand that many other studies need to be conducted to interpret the individual leak types and their contribution, specifically from natural gas production.
ReplyDeleteI agree with you when you say it's problematic that the Guardian author tried to compare the estimated methane emissions worldwide to a single gas leak. I suspect the purpose was to add shock factor for people that are just skimming this article. If the reader was actually paying attention to what he's writing, they would probably know that it's not shocking that the total worldwide industrial methane emission is 300 times higher than a single gas leak in the U.S.
ReplyDeleteNice job, Mairen! Thank you for picking up the latest article that draws our attention to the greenhouse gas methane. And I agree with Aubrey's comment, and when there tend to be mountainous data in the report, it is of great importance to illustrate each number clearly, otherwise readers will feel confused. The figure is helpful to demonstrate the fraction of methane emissions that come from the fossil fuel industry, compared to the other sources, but is simplistic and does not accurately portray the findings in the Nature paper. Otherwise, the article does provide a way for us to view methane from industry again.
ReplyDeleteI like and agree with the point that you made at the end of your post. A major downfall of the Guardian article is their failure to mention industrial agriculture as the "largest worldwide contributor to methane emissions." In terms of how to curb methane emissions in order to lead to beneficial effects, I think that their discussion would be more meaningful to readers if it were to include more factors than just the fossil fuel industry.
ReplyDeleteI agree that the Guardian article did a reasonable job conveying the main themes of the Nature paper. However, I think they could have provided a more robust background about greenhouse gases. For example, I think your explanation methane's of CO2 equivalents was much more useful than the explanation provided in the Guardian article that simply stated the increased global warming potential of methane. I think that in these types of articles it is important to educate the reader with facts and, as you pointed out, that the Guardian article could have been better about this.
ReplyDeleteI enjoyed reading the Guardian article and always find the most interesting parts to be quotes from the authors in mass media. In contrast with everyone else, I found the Aliso Canyon comparison to be a helpful jumping off point to think about the magnitude of emissions because I, I'm guessing along with the average reader of the Guardian, don't have much experience or concept of emissions huge magnitudes. For example, the linked Guardian article says the Aliso Canyon leak put out enough methane each day to fill a balloon the size of the Rose Bowl, or even more helpful, an output roughly equal to the annual output of a medium sized EU country- I can start to approach picturing what 300 times that amount might be.
ReplyDeleteAlso interesting to me was the chance to learn a bit about "natural geological seepage" which comprised a larger proportion than I expected. Thanks!
I think this is a really good blog post in terms of summarizing both articles, and you make quite a few points that I agree with. I agree with Liz that your explanation of methane's CO2 equivalents was well done, but I would have liked you to better specify what was meant by "natural gas methane seepage". I'm especially curious what is being done or what can be done to curb this source of methane in addition to the agricultural and fossil fuel industries.
ReplyDeleteA thought that crosses my mind when reading The Guardian article and the Nature publication is do we need to re-evaluate other greenhouse gasses? Being that this is a very recent publication, I believe it may have a large impact on the way scientists evaluate greenhouse gasses in general. It is good to see that scientists are continuously re-evaluating this field of research. These discoveries show that improvements can always be made. Hopefully this recent publication will spark others to re-evaluate there methods, which could lead to more accurate data/information. I'm glad The Guardian did not go into detail on the methods the publication used. This left the more interested (or scientifically minded) people to seek to publication. Great post Mairen!
ReplyDeleteI find it pretty interesting that all of the "new" methane emission levels seem to have some pretty substantial uncertainty with them. Was it ever commented on that or would you happen to know why the new levels are between 20-100% higher than previously thought? I think this difference of 60% is pretty substantial and how can we be sure that these new levels are accurate when there is such a divide?
ReplyDeleteI enjoyed your summary of both the Nature and Guardian articles. It was very concise and you had some thought provoking ideas about the Guardian article. You mentioned that the article didn't include the largest source of methane emissions, which is industrial farming.Since the article focused on anthropogenic sources of methane, I wonder if they thought that industrial farming didn't count as anthropogenic since cows are living organisms. Or if there was some kind of similar explanation for not including industrial farming in the article.
ReplyDeleteThe article also mentions that if methane emissions are reduced now then climate forcing will also be reduced in only a few years and these effects would not be seen as soon if there is a reduction of CO2 emissions now. While I think that it is important to reduce methane emissions, the article almost made it sound like it was unimportant to focus on reducing CO2 emissions as well. I think that is a dangerous idea since CO2 emission make up three-quarters of global greenhouse emissions.
Mairen, I agree with you. I think that the article should have mentioned the major contributors of methane gas through agriculture. Being from South America I can say that much of the population in this part of the world is engaged in this activity due to the fertile soil and temperate weather in most of the regions. Currently, this is one of the most productive sectors in this region. Due to the diversity of agricultural products and livestock, Latin American countries are trying to increase their international competition with European countries. Unfortunately, the high demand for agriculture makes Latin America one of the regions with the biggest production of this kind of emissions in conjunction with the Caribbean. It is regrettable that the authorities haven’t taken sufficient measures to reduce the emission of these pollutants. However, I believe that reducing the emission of methane and other air pollutants can be achieved through the adoption of improved production practices and by establishing controls on the emissions of these gases.
ReplyDeleteNice job! I agree with you when you say that the author did a good job on stating key points but I do believe the author did leave out some other key points. The article made it seem like all emissions were due to gas leaks which is not the case. the article could have been trying to gear towards telling people that this is a large factor in the production of greenhouse gases, but should have touched on the others. there are also so many different types of gas leaks. i feel the author could have done a better job elaborating more on this topic and the other sources of greenhouse gases.
ReplyDeleteVery thorough analysis, great job! Thanks for the background on the greenhouse effect and greenhouse gasses. This will be a very helpful precursor to this week's lecture. I also liked that you chose to focus your article on methane emissions, especially since when most people hear global warming, they by default think about CO2.
ReplyDeleteIt's alarming that methane emissions from fossil fuels could be double what we originally thought. This would definitely have implications about the accuracy of current climate prediction models. The underestimation of natural gas, oil, and coal production emissions makes me wonder if this could be due to unaccounted emissions from developing countries.
I agree with your rating for the Guardian article. I would've also given it a higher score if it had mentioned the largest worldwide contributor to methane emissions.
This is certainly an interesting choice of articles. Looking at the numbers they sight, it is remarkable that the greenhouse gas emission estimates were originally so low. Do they comment on why the original estimates were substantially lower? Perhaps it is because the instrumentation was not quite as sophisticated as they are today.
ReplyDeleteNicely done! I agree that the Guardian article did a fairly good job explaining the science to a someone with a non-scientific background. However, I think that the oversight with regard to the figure is actually a big problem. Consider how many people read a headline, skim a paragraph or two, and take a long look at the figures and captions. For anybody who does this in lieu of reading the article, they may not get important context and information. While not everybody does this, I think that makes it particularly important given today's lazy, headline and soundbite dominated culture. Overall, though, I agree with your assessment. Again, nicely done!
ReplyDeleteAfter reading the Guardian article, I found it hard to discern whether the author was trying to communicate that overall emissions were larger than thought, or if the percent of methane emissions attributable to the fossil fuel industry was greater than previously estimated.
ReplyDeleteGreat article choice! It was really cool to see a major news outlet commenting on the key facts of a scientific article and topic while making it relevant to the general reading audience. Though, like you had stated, this isn't perfect coverage, and most people reading the Guardian would have probably understood some of the more technical aspects, and the fact that there needs to be a variety of testing done and data points collected before any definitive statement can be made.
ReplyDeleteI agree that that Gaurdian article does a nice job summarizing the the important information from the Nature publication, without bogging the reader own with too many complicated details. It is important to be able to reasonably communicate scientific findings to the general public, and I think that this article did a nice job. I thought the last quote included in the Guardian article was interesting, though. The author quotes the Nature publication, noting, “a key message is that the number and comprehensiveness of measurements matter". This quote is almost ironic as some of the data provided in the article, such as failing to differentiate between adjusted and unadjusted measurements in the author's discussion, does not so the measurements justice, and may misrepresent some data. It is not just important to compile all of the data, but to interpret and explain it sufficiently. Overall though, I thought it was a very informative and accurate summary of the Nature paper.
ReplyDeleteI also appreciated how the Guardian article provided a clear summary of the research highlights from the Nature article. The author also included quotes/additional information from other sources, as well as more simplistic figures to illustrate the key findings from the paper, which was also pretty helpful for the general reader. Although, like you mentioned, a lot more data (especially regarding methane emissions from non-industrial sources) also needs to be taken into consideration before a definitive statement can be made about the dramatic increase in methane emissions. I also agree with Christopher's comment on the accuracy of instrumentation used today vs. 20 years ago.
ReplyDeleteI liked this blog post as I generally am most aware of CO2 emissions as being a major contributor to global warming due to how much humans release into the atmosphere. I was glad to read that efforts in reducing methane would also have a substantial impact on curbing global warming. I did not know this and I also thought it was especially interesting that methane has a larger effect over a shorter period of time due to its lifetime. I am mostly left curious as to the mechanism methane can play in ozone formation in the troposphere and on occasion, what you mean by "the fossil fuel industry." I was not sure if you were just referring to the methane sources you had mentioned, were talking about specific industrial processes that produced greenhouse gases in the general sense, or the industries that purposely generate fossil fuels for energy. Otherwise, very informative post!
ReplyDeleteAs I mentioned in class, why are we not more worried about this problem? The Nature publication is good in that it provides new data and techniques for collecting information and informing us. I just wish the publication made greater attempts at influencing policy. I also, in a bigger picture, am interested in what could be done about this issue of methane production. Do we just stop doing these processes or can we change, improve, or modify the process to reduce methane production? I wonder what the equivalent "montreal protocol" for increased temperature and greenhouse gas pollutants would look like and who will take on the task.
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