Talk Title: From Land Carbon Sink to Net Zero Emissions: How can Land be Part of the Climate Solution?

The land biosphere plays a major natural contribution to climate stability by removing around one third of anthropogenic CO2 emissions from the atmosphere each year. However, anthropogenic disturbances of the land biosphere such as reactive nitrogen enrichment have altered ecosystem carbon and nitrogen cycling, and the resulting increases in the emissions of non-CO2 greenhouse gases (CH4 and N2O) in particular can contribute to climate change. By integrating all three major GHGs (CO2, CH4 and N2O) together, our study shows that the cumulative warming capacity of concurrent biogenic CH4 and N2O is a factor of about two larger than the cooling effect resulting from the global land carbon sink. Land-use intensification using today’s practices to meet food and energy demands increases anthropogenic GHG emissions, which is not consistent with stabilizing the climate at low temperature scenarios. To achieve net-zero GHG emissions, it is essential to adopt climate-smart agriculture, forestry and land use practices to enhance carbon storage as well as reduce non-CO2 GHG emissions. The future role of the land biosphere on achieving Net-Zero emissions will depend on future land-use intensification pathways and on the evolution of the land carbon sink. Therefore, how we manage the global lands needs to become a central part in our strategy to mitigate climate change.

About the Presenter:

Dr. Hanqin Tian is Schiller Institute Professor of Global Sustainability and Professor of Earth and Environmental Sciences at Boston College. Dr. Tian has worked across the disciplinary lines of earth system science, ecology, biogeochemistry, hydrology, earth system modeling, remote sensing and data science. His research on global carbon and nitrogen cycling and greenhouse gas emissions is at the leading edge of the field. His research has resulted in 360 peer-reviewed research articles published in most prestigious journals including over 30 papers in Nature, Science, PNAS and their sister journals. Dr. Tian is a Highly Cited Researcher ranked by Clarivate Web of Science. He was also ranked among the world’s most influential climate scientists by the Reuters List. Dr. Tian is a coordinating lead author for the International Nitrogen Assessment and a contributing author for IPCC AR6. He has served on the Steering Scientific Committee of Global Carbon Project (GCP) and Co-Chair of the International Scientific Committee for Global Nitrous Oxide Budget Assessment. Dr. Tian is elected Fellow of American Association for the Advancement of Science (AAAS), American Geophysical Union (AGU), and Ecological Society of America (ESA). He was named an Andrew Carnegie Fellow (Brainy Award) in 2019.