In the heart of France, at the Laboratoire des Sciences du Climat et de l’Environnement, a team of scientists led by Dr. Marielle Saunois has been meticulously unraveling the mysteries of methane, a potent greenhouse gas that’s second only to carbon dioxide in its impact on climate change. Their latest findings, published in the Earth System Science Data journal, offer a comprehensive global methane budget from 2000 to 2020, providing crucial insights for industries, particularly the energy sector, as they navigate the complexities of climate mitigation.
Methane, often overlooked in favor of its more infamous counterpart, carbon dioxide, is a significant player in the climate change game. Its atmospheric concentrations have been rising since 2007, and its shorter lifespan and stronger radiative effect make it a critical factor in temperature changes. “The relative importance of methane emissions compared to those of CO2 for temperature change is related to its shorter atmospheric lifetime, stronger radiative effect, and acceleration in atmospheric growth rate over the past decade,” Saunois explains. This acceleration, however, remains a topic of debate, with diverse and overlapping sources making it challenging to pinpoint the exact causes.
The research, a collaborative effort under the Global Carbon Project, integrates both top-down (atmospheric observations and inversions) and bottom-up (process-based models and inventories) approaches to quantify methane emissions. The results are striking: global methane emissions for the 2010-2019 decade are estimated at 575 Tg CH4 yr-1, with approximately 65% attributed to direct anthropogenic sources in the fossil, agriculture, and waste sectors.
For the energy sector, these findings are particularly relevant. Fossil fuel emissions contributed 115 Tg CH4 yr-1 in the top-down budget and 120 Tg CH4 yr-1 in the bottom-up budget. These numbers underscore the urgent need for the industry to address methane leaks and emissions, not just for environmental reasons, but also for economic ones. Methane, after all, is a valuable resource that, when captured, can be used to generate electricity or heat.
The study also highlights the importance of wetlands and inland freshwaters as natural methane sources, with combined emissions averaging 248 Tg CH4 yr-1 for the 2010-2019 decade. Human activities, through climate change, eutrophication, and land use, perturb these natural fluxes, making it even more challenging to quantify and mitigate methane emissions.
Looking ahead, the research identifies several priorities for improving the methane budget, including the development of high-resolution maps of water-saturated soils, intensification of methane observations, and improvements in transport models. These efforts could pave the way for more accurate methane tracking and mitigation strategies, benefiting industries and the environment alike.
The data presented in this study, published in the Earth System Science Data journal, which translates to ‘Earth System Science Data’ in English, is a significant step forward in our understanding of methane and its role in climate change. It’s a call to action for industries, particularly the energy sector, to take methane emissions seriously and to invest in technologies and practices that can help mitigate this potent greenhouse gas. As Saunois puts it, “The most important source of uncertainty in the global methane budget is still attributable to natural emissions, especially those from wetlands and inland freshwaters.” Addressing this uncertainty is crucial for developing effective climate mitigation strategies. The future of methane research, and indeed the future of our climate, depends on it.