Periodic Reporting for period 1 - FORM (Quantification of FOssil methane emissions using Radiocarbon measurements of atmospheric Methane)
Okres sprawozdawczy: 2022-05-01 do 2024-04-30
Methane (CH4) is the second most important anthropogenic greenhouse gas (GHG) but has a lifetime much shorter than carbon dioxide (10 yrs compared to millennia). This means that mitigation strategies could have a rapid effect on global warming, making methane one of the main targets of climate policy. A sudden increase in the atmospheric CH4 concentration has been observed during the last decade but there is still no consensus on the causes of this rapid CH4 growth. This is an immense challenge to society - if CH4 sources are not clearly identified and their emissions controlled, it will be very difficult indeed to meet the goals of the United Nations Paris Agreement on Climate Change adopted in December 2015, including limiting global temperature rise “well below 2 degrees Celsius”.
Several studies found that observations highly differ from the inventories estimates, especially in the attribution of the emissions to specific source sectors.. Therefore, new constraints are needed to accurately attribute emitted methane to fossil fuel sources or other anthropogenic sources or natural processes.In this context, radiocarbon (14C) is a very powerful tool as 14C measurements provide the most accurate way of identifying fossil fuel-derived methane in air. Fossil carbon is entirely depleted in 14C, having lost it all after millions of years of radioactive decay during burial underground (14C half time is 5730 years). When emitted into the atmosphere, fossil-derived methane will cause a strong decrease into the atmospheric radiocarbon ratio 14C/C (Δ14C) that can be quantified. Despite their incredible usefulness, at present there are very few published Δ14CH4 measurements, because ambient methane levels are low (~ 2 ppm) and hundreds of litres of air need to be sampled and processed to obtain enough CH4 for 14C analysis.
Within the FORM project, the researcher aimed to produce new Δ14CH4 measurements to yield answers to these fundamental scientific questions:
Q1) Which methane sources need to be targeted for a more effective reduction of methane emissions?
Q2) How accurate are methane emissions estimates for urban environments?
These scientific questions were answered by developing a portable methane sampling device for analysis of small-sized carbon samples, a key feature for ambient air samples containing typically only 2 ppm of methane.
Several studies found that observations highly differ from the inventories estimates, especially in the attribution of the emissions to specific source sectors.. Therefore, new constraints are needed to accurately attribute emitted methane to fossil fuel sources or other anthropogenic sources or natural processes.In this context, radiocarbon (14C) is a very powerful tool as 14C measurements provide the most accurate way of identifying fossil fuel-derived methane in air. Fossil carbon is entirely depleted in 14C, having lost it all after millions of years of radioactive decay during burial underground (14C half time is 5730 years). When emitted into the atmosphere, fossil-derived methane will cause a strong decrease into the atmospheric radiocarbon ratio 14C/C (Δ14C) that can be quantified. Despite their incredible usefulness, at present there are very few published Δ14CH4 measurements, because ambient methane levels are low (~ 2 ppm) and hundreds of litres of air need to be sampled and processed to obtain enough CH4 for 14C analysis.
Within the FORM project, the researcher aimed to produce new Δ14CH4 measurements to yield answers to these fundamental scientific questions:
Q1) Which methane sources need to be targeted for a more effective reduction of methane emissions?
Q2) How accurate are methane emissions estimates for urban environments?
These scientific questions were answered by developing a portable methane sampling device for analysis of small-sized carbon samples, a key feature for ambient air samples containing typically only 2 ppm of methane.
A new sampling system is now available for routine measurements of 14CH4. The new system enables extraction of carbon from CH4 while sampling in the field, reducing the sample processing in the laboratory and allowing collection of a hundred liters of air onto a 0.5 g zeolite trap. This new system greatly facilitates 14CH4 measurements, and it represents a break-through into the detection and quantification of methane emissions. An image of the methane sampling device is attached. The whole system fits well into a box of 80 x 40 x 30 cm and runs either on 115/230 V AC or 48 V DC provided by a battery pack.
Major parts of the system are: 1) Nafion dryer (mostly hidden underneath), 2) Pumps (partially hidden), 3) CO2 trap, 4) Flow controller, 5) Furnace for CH4 combustion, 6) Sample trap with Peltier coolers, 7) CO2 sensor
The new sampler is novel and one of its kind. The main features are 1) the CH4 carbon extraction while sampling, which greatly reduces the sample processing at the radiocarbon laboratory; 2) the system portability; 3) the fact that the sampler enables collection of several samples a day, and 4) that it is interfaced directly with leading-edge accelerator mass spectrometry facilities for radiocarbon measurements in the Ion Beam Physics group.
The use of the new sampler opens a new research field. 14CH4 measurements were not carried out routinely, and only by very few laboratories worldwide, due to the complexity of such measurements. The system, being very user friendly and enabling collection of small samples, will expand the capacity of 14CH4 measurements, providing insights into the methane budget. The sampler also enables high precision measurements (5‰), better than the most recent methodologies used for 14CH4 analysis, and therefore allows a more accurate quantification of methane emissions. The system is currently available at LIP, laboratory of Ion Beam Physics, and it will be employed in future PhD and master projects at ETH.
A first inter laboratory comparison has been performed, between the extraction system for 14CH4 analysis at ETH and at the University of Bern. The 14CH4 values measured from the same reference gases are comparable, showing that the new technology developed in this project produces results as accurate as previous techniques, which have been already published.
Secondments
The researcher has visited the AMS laboratory of the University of Bern (LARA), and she has been trained for the extraction of the sample for 14CH4 analysis. This secondment has been extremely useful, because it gave to the researcher the opportunity to compare different techniques and have a better understanding of what is needed for a greater accuracy of the measurements. With the secondment at EMPA , the researcher learnt the use of the atmospheric model FLEXPART. The researcher has now all the tools to run the model, although she is not very proficient due to the lack of time for running the simulations.
The system is currently available at LIP, laboratory of Ion Beam Physics, and it will be employed in future PhD and master projects at ETH.
Researcher's training
The researcher has been trained on the use of MICADAS AMS system for 14C analysis, on the sample preparation for the gas interface of the Micadas system, and on the construction of some parts of the system, such as a little furnace and sample traps of zeolite (T1). The researcher started also the training on the use of the model FLEXPART and she attempted few simulations (T2).
Major parts of the system are: 1) Nafion dryer (mostly hidden underneath), 2) Pumps (partially hidden), 3) CO2 trap, 4) Flow controller, 5) Furnace for CH4 combustion, 6) Sample trap with Peltier coolers, 7) CO2 sensor
The new sampler is novel and one of its kind. The main features are 1) the CH4 carbon extraction while sampling, which greatly reduces the sample processing at the radiocarbon laboratory; 2) the system portability; 3) the fact that the sampler enables collection of several samples a day, and 4) that it is interfaced directly with leading-edge accelerator mass spectrometry facilities for radiocarbon measurements in the Ion Beam Physics group.
The use of the new sampler opens a new research field. 14CH4 measurements were not carried out routinely, and only by very few laboratories worldwide, due to the complexity of such measurements. The system, being very user friendly and enabling collection of small samples, will expand the capacity of 14CH4 measurements, providing insights into the methane budget. The sampler also enables high precision measurements (5‰), better than the most recent methodologies used for 14CH4 analysis, and therefore allows a more accurate quantification of methane emissions. The system is currently available at LIP, laboratory of Ion Beam Physics, and it will be employed in future PhD and master projects at ETH.
A first inter laboratory comparison has been performed, between the extraction system for 14CH4 analysis at ETH and at the University of Bern. The 14CH4 values measured from the same reference gases are comparable, showing that the new technology developed in this project produces results as accurate as previous techniques, which have been already published.
Secondments
The researcher has visited the AMS laboratory of the University of Bern (LARA), and she has been trained for the extraction of the sample for 14CH4 analysis. This secondment has been extremely useful, because it gave to the researcher the opportunity to compare different techniques and have a better understanding of what is needed for a greater accuracy of the measurements. With the secondment at EMPA , the researcher learnt the use of the atmospheric model FLEXPART. The researcher has now all the tools to run the model, although she is not very proficient due to the lack of time for running the simulations.
The system is currently available at LIP, laboratory of Ion Beam Physics, and it will be employed in future PhD and master projects at ETH.
Researcher's training
The researcher has been trained on the use of MICADAS AMS system for 14C analysis, on the sample preparation for the gas interface of the Micadas system, and on the construction of some parts of the system, such as a little furnace and sample traps of zeolite (T1). The researcher started also the training on the use of the model FLEXPART and she attempted few simulations (T2).
Impact on the researcher's career
The researcher gained new laboratory and modelling skills, which made her particularly qualified in the field of atmospheric science. She has been offered a permanent position in a research institute in Italy (RSE, Research on the Energetic Systems), where she is now managing a laboratory of atmospheric science at Plateau Rosa, and she is providing technical support to the Italian government for the monitoring of greenhouse gases emissions.
Innovation and important benefits for society
The worked carried out has overcame the technical limitations related to 14CH4 measurements, and opened-up a new field of research. For the first time such measurements can be used as a systematic tool for source apportionment of methane emissions, addressing the increasing need of understanding the recent methane growth rate. Routine 14CH4 measurements will provide further insights into the main methane sources, helping with targeting specific emission sectors for greenhouse gases reductions. The new technology developed in this project will also create new collaboration opportunities for ETH and the researcher, both with governments and other universities.
This project constitutes an advancement in the field of quantifying methane emissions. As such it provides a new scientific tool for supporting countries in the Global Methane Pledge (GMP), a voluntary framework where nations commit to take action to reduce methane emissions by 30% from 2020 levels by 2030.
The researcher gained new laboratory and modelling skills, which made her particularly qualified in the field of atmospheric science. She has been offered a permanent position in a research institute in Italy (RSE, Research on the Energetic Systems), where she is now managing a laboratory of atmospheric science at Plateau Rosa, and she is providing technical support to the Italian government for the monitoring of greenhouse gases emissions.
Innovation and important benefits for society
The worked carried out has overcame the technical limitations related to 14CH4 measurements, and opened-up a new field of research. For the first time such measurements can be used as a systematic tool for source apportionment of methane emissions, addressing the increasing need of understanding the recent methane growth rate. Routine 14CH4 measurements will provide further insights into the main methane sources, helping with targeting specific emission sectors for greenhouse gases reductions. The new technology developed in this project will also create new collaboration opportunities for ETH and the researcher, both with governments and other universities.
This project constitutes an advancement in the field of quantifying methane emissions. As such it provides a new scientific tool for supporting countries in the Global Methane Pledge (GMP), a voluntary framework where nations commit to take action to reduce methane emissions by 30% from 2020 levels by 2030.