Global aviation emissions in 2019 far exceed official reports, reveals study

This discovery reveals a significant under-reporting issue that could have profound implications for international climate policy.


A groundbreaking study has exposed a staggering discrepancy in aviation emissions reported for 2019, revealing that actual emissions were nearly 300 million metric tons higher than figures provided to the United Nations. This discovery reveals a significant under-reporting issue that could have profound implications for international climate policy.

The United Nations Framework Convention on Climate Change (UNFCCC), established in 1992, mandates member countries to report their annual emissions. While developed countries (Annex I) have stringent reporting requirements, developing nations (non-Annex I) are not obligated to submit aviation emissions data, though they may opt to do so. This bifurcation in reporting standards has led to substantial gaps in global emissions data, particularly from rapidly industrializing nations.

In a meticulous analysis, scientists evaluated over 40 million flights from 2019, involving 197 countries. Their research, published in the journal Environmental Research Letters, utilized a high-resolution aviation transport emissions assessment model to calculate a more accurate figure of 911 million metric tons of CO2 emissions—over 50% higher than the 604 million metric tons reported.

The United States topped the list of countries with the highest aviation-related emissions, encompassing both international and domestic flights. Surprisingly, China, which did not report its flight emissions in 2019, emerged as the second-largest emitter, highlighting a critical data omission in global reporting.

The study not only recalculated carbon dioxide emissions but also included other harmful pollutants such as nitrogen oxides, sulfur oxides, unburned hydrocarbons, black carbon, and organic carbon. This comprehensive approach sheds light on the broader environmental impact of aviation, which extends beyond simple CO2 metrics.

The model used by the researchers represents a significant advancement in environmental science, allowing for almost real-time monitoring of aviation emissions. This capability marks a significant shift from traditional methods that rely on annual reports from statistical offices, which can lag by a year or more. Anders Hammer Strømman, co-author of the study and a professor at the Norwegian University of Science and Technology, highlighted the potential of this technology, stating, “This model allows us to do instant emissions modeling—we can calculate the emissions from global aviation as it happens.”

The revelation of such vast underreporting in aviation emissions has ignited a call for urgent reevaluation of how emissions data are collected and reported. Accurate and timely data are crucial for setting realistic climate goals and ensuring that countries are held accountable for their environmental impact. The study’s findings are particularly timely, given the growing pressure to meet the net-zero emissions targets by 2050 set by the International Energy Agency.

With the new data, policymakers and environmental groups are advocating for a standardized, transparent reporting mechanism that includes non-Annex I countries in the emissions reporting process. Enhanced global cooperation and technology transfer might enable these countries to implement the necessary monitoring and reporting infrastructure.

Helene Muri, co-author of the study and a research professor at the Norwegian University of Science and Technology, said: “Now we have a much clearer picture of aviation emissions per country, including previously unreported emissions, which tells you something about how we can go about reducing them.”


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Ruth Milka started as an intern for NationofChange in 2015. Known for her thoughtful and thorough approach, Ruth is committed to shedding light on the intersection of environmental issues and their impact on human communities. Her reporting consistently highlights the urgency of environmental challenges while emphasizing the human stories at the heart of these issues. Ruth’s work is driven by a passion for truth and a dedication to informing the public about critical global matters concerning the environment and human rights.