This list shows the 25 sites in the oil and gas sector with the largest detected and quantified emissions rates worldwide, as seen by key satellite instruments in 2025. (We published an initial list in November here.)

These insights come from Carbon Mapper’s methane emissions data leveraging two space-based instruments: Planet Labs’ Tanager-1 satellite and NASA’s EMIT instrument on the International Space Station. The non-profit Carbon Mapper processes the raw data from these instruments to detect, quantify, and pinpoint methane plumes, publishing the results on its data portal. Using published Carbon Mapper data, we determined the oil and gas sector sources with the highest detected hourly emissions rates seen from Jan. 1, 2025, to Dec. 31, 2025. 

The 2025 data show 4,404 plumes observed at 2,489 oil and gas sector sites worldwide. These are sites in dozens of countries of all income levels and in all world regions. The sources on our “Top 25” list are responsible for the most acute hourly emission rates seen by these instruments globally – with emission rates ranging from 3.7 to 10.5 tonnes (metric tons) of methane per hour. Notably, the sources on this Top 25 list are concentrated in just a few countries, with the majority of the list consisting of oil and gas sites in Turkmenistan. Top 25 sites are also located in Venezuela, Iran, Pakistan, and the United States. 

The sources presented here have been observed at least twice, and the emission rate reported for each site takes into account the number of times a plume was detected at that site. As the ability and coverage of space-based methane monitoring expands, further assessment of these sites and their emissions will become more reliable Still, the list presented here is a snapshot showing where the largest sources of oil & gas methane emissions are likely located globally, and highlights opportunities for near term mitigation. 

In this iteration of our Top 25 list, we are including a new column: potentially responsible operator. This information was not obtained directly from Carbon Mapper. Instead, the information is the result of research conducted by our team at the Emmett Institute. Below, we explain the methodology for that research and welcome feedback.   

Notes to understand and interpret this data: 

How important are these sources of emissions in the global context? To illustrate how important these sources are, and what big opportunities they present for near-term reductions, consider that over a year, a source emitting 5 tonnes of methane per hour (in the middle of the pack of our “top 25” list) would contribute about as much to global warming as one million SUVs or one large (500 megawatt) coal-fired power plant. 

How did we calculate these emissions rates?  We didn’t do the calculations. We are reporting calculations done by Carbon Mapper and included on their public data portal, making some judgment calls about what to include or exclude from our list as we explain below. Carbon Mapper gives source emission rates by averaging the emission rates from each time an instrument observed a source (including times, if any, when no emissions were observed). Carbon Mapper’s methodology for calculating emissions rate is described in more detail here. We obtained source-level methane emission data from Carbon Mapper’s data portal for the year 2025. Then we sorted and selected for the 25 largest emitters in the Oil & Gas category. For those observations, we used an automated process to pull associated emission information and location data from Carbon Mapper. We then used that location data to manually attribute each observation to a specific potentially responsible operator, which we explain at greater length below. For more questions about our methodology, please reach out to Horowitz@law.ucla.edu.  

What do the two satellite instruments observe?  Tanager specifically images key regions of the globe where there are known oil & gas production activities, returning to those areas on a recurring basis (e.g., every few months). EMIT observes broad spatial areas in between 50°S - 50°N, including many oil & gas fields, as part of its broad earth science mission. 

Why do our emissions rates look a little different than those reported on the Carbon Mapper site, e.g., the largest source is 10.5K kg per hour on Carbon Mapper and 10.5 tonnes per hour on our ranking?  We are reporting the same emission rates but are translating them into a different unit to make it simpler. One tonne (aka metric ton) equals 1,000 kilograms. Because the Carbon Mapper portal has to provide consistent formatting for hundreds of sources whose emissions rates vary from very small to very large, it uses the smaller unit (kg/hr). Since the Top 25 sources all have emissions rates in the tonnes range, we state them as tonnes, to make it simpler and to avoid having to say “10.0 K Kg.” Our emission rate for any given Top 25 site may also diverge over time from Carbon Mapper’s number for that same site, as Carbon Mapper updates its database to include additional observations of that site.  

Does the list include every big emissions event the satellites saw?  No. Because of differences in the satellites’ orbits, some of these sources were seen many times in 2025, others just a few times. To be careful, we only included sources that were observed at least twice. So, there are a few oil and gas sector sources with extremely high emissions rates that appear on Carbon Mapper’s portal, but that we excluded from this list because they were observed only once. 

Where can I learn more about methane observation from satellites?  To learn more about remote observation of methane and the opportunities and limitations presented by the new satellite data, see the Emmett Institute’s “Remote Sensing of Atmospheric Methane: A Primer for Policymakers on the Science of Methane Satellites.” 

How did we determine potentially responsible operator information? In this iteration of our Top 25 list, we are including a “potentially responsible operator” column. This information was not obtained directly from Carbon Mapper. Instead, the information is the result of research conducted by our team at the UCLA Emmett Institute. We drew our conclusions from a holistic review of the best publicly available evidence. The amount of information available to us was heavily dependent on the emission source’s location.  

Take, for example, the emissions in Stanton, Texas. Based on geodata and satellite imagery, we were able to confirm this source as either the Lenorah or Red Lake plant, which are both owned and operated by Energy Transfer. Detailed location and ownership data sourced from the Texas Commission on Environmental Quality helped us reach that determination.  

In other instances, our determinations were based on a process of elimination. We assigned all sites in Turkmenistan to either Turkmengaz or Turkmennebit, the state-owned natural gas and state-owned oil companies, respectively. Due to a dearth of publicly available data, we have no direct confirmation that these sites are operated by Turkmenistan’s state-owned firms. However, we do know that the state largely restricts non-state-owned firms from operating onshore projects. Of the third-party firms that operate onshore oil and gas wells, only the Italian firm Eni appears to operate in an area near our detection sites. The Emmett Institute reached out to Eni, which confirmed that they had no active operations at the coordinates where plumes were detected. This leads us to conclude that state-owned firms are the potentially responsible operator for the sites included in this list. We welcome questions about our methodology, including questions about supporting evidence for operator information. 

Something on the list doesn’t look right. Think we’ve got something wrong? Do you know something about one of these sources that suggests there’s an error in Carbon Mapper’s observation and calculation or our compilation and interpretation? If so, please explain it to us here.