Revealing the Truth About the World’s Greenhouse Gas Emissions

Washington Post journalist and Pulitzer-Prize winning reporter Chris Mooney gave a talk entitled “Revealing the Truth About the World’s Greenhouse Gas Emissions” Friday December 10th 2021, sponsored by the Yale Center for Environmental Communication and the Yale Environmental Data Science Initiative at the Yale School of the Environment. 

Mooney discussed his months-long Washington Post investigation into the world’s climate-warming emissions, which found that countries are dramatically under-reporting their climate impact—by as much as 13 billion tons of greenhouse gasses annually. The Post drew on satellite and atmospheric analyses, independent scientific inventories of greenhouse gasses, and a dataset built by the paper itself to hold the entire world accountable for what it is truly emitting. 

Here are some key takeaways: 

  1. Countries are massively underreporting their GHG emissions by more than 10 billion tons annually. That is the gap between what scientists estimate the world to be emitting and the aggregated reported emissions of each individual nation. Most of the gap in reported emissions comes from land-use, land-use change, and forestry (LULUCF). While part of the gap can be explained through factors including using out-of-date data; doubts about how to account for international shipping; and calculated differences between the global warming potential of different gases, it is mostly from incorrect reporting from nations. For instance, Malaysia claims that none of its natural forests have been converted to plantations despite conflicting satellite imagery (plantations release massive amounts of CO2).  Malaysia also claims that its forests uptake the same amount of CO2 as Indonesia, whose forested lands are five times larger. Generally, nations manipulate their LULUCF emissions reporting by (a) claiming natural CO2 uptake by forests is “man-made” and so should be considered to offset anthropogenic emissions from industry, (b) exaggerating the amount of CO2 being taken up by forests, and (c) minimizing the CO2 emitted from deforestation and forest degradation.
  2. Countries can get away with this because reporting to the UNFCCC is both irregular and poorly reviewed. Annex 1 nations, about 40 developed nations mostly in the global North, regularly and fully report. Yet developing nations, which number over 140 and include the majority of tropical forested nations such as Brazil, Congo-Kinshasa, and Indonesia, report irregularly and often in different formats and with different units. Not only does this hamper data aggregation and analysis, but updated understandings of scientific concepts are present in some and absent in others. For instance, the estimate of the global warming potential of methane has been updated from 21 to 28 times that of CO2 in recent years. But not all countries are using the latest estimate in the reports they submit to the UNFCCC. While it is a part of the Paris Agreement to make these reports more regular and uniform under the “Enhanced Transparency Initiative,” inconsistencies will likely persist for a long time. The impact of such discrepancies on countries’ commitments to reducing emissions is unclear, but will likely make it more difficult for them to faithfully fulfill their GHG reduction pledges.
  3. The method of reporting utilized to generate these insights are an example of Data Journalism. A growing number of major news outlets are creating data journalism groups, including the Washington Post. Mooney’s starting point for this project included reviewing the existing scientific literature on GHG emissions, and then identifying inconsistencies between scientific findings and nations’ reported CO2 emissions. Mooney explained that investigative reporting of this kind involves both reviewing public databases and aggregating data sources into new data sets, which is exactly what he and his team did in this case. Chris Mooney is both lecturing in the Yale School of the Environment (YSE) and working with the YSE’s Data Science Initiative on similar endeavors in the spring of 2022.


The talk was moderated by Dr. Jennifer Marlon, a Research Scientist at the Yale School of the Environment and the Yale Program on Climate Change Communication (YPCCC).  She studies public perceptions of and responses to environmental change, particularly extreme weather events. 

Chris Mooney is a Pulitzer Prize winning reporter on energy and the environment at The Washington Post.  He is also a lecturer at the Yale School of the Environment for this academic year. He has authored four books about science, politics and climate change.