Fall Webinar Series: The History and Future of the Atmosphere

Join colleagues for the first Fall 2025 Webinar Series

The History and Future of the Atmosphere: Historical Emissions Data and CMIP7

Dr. Steven Smith
University of Maryland, Center for Global Sustainability

Thursday, August 28, 2025
from 4 to 5 p.m.
Via Zoom --  Register here

Abstract: Emissions of reactive air pollutant species and aerosols impact human health, ecosystesm, cloud formation and evolution, and Earth's radiative balance. The talk will present estimates of global anthropogenic air pollutant emissions from 1750 to 2024 produced by the Community Earth atmospheric Data System (CEDS). On a global level, emissions of some air pollutant species have been generally declining for several decades, (SO2, CO), while others have been decreasing only within the last two decades (NOx, BC, OC), with some stable or still increasing (NMVOC, NH3). The trends of these emissions will be discussed.

CEDS emissions will be used as the historical forcing data for the next phase of CMIP, CMIP7, with historical simulations starting soon. The design of CMIP7 will be discussed, including how CMIP7 is different from previous rounds, including a near-term set of CMIP7-Fast Track simulations, and a change to how historical data is used designed to facilitate extension of CMIP7 historical model ensembles. 

The future scenario datasets for CMIP7-Fast Track are now being developed and will be released over this fall for use in foundational Earth system model experiments designed to explore a range of possible forcing tajectories over the 21st century and beyond. New scenarios from GCAM, developed by an international collaboration will also be briefly discussed.

BIO: Dr. Steven J. Smith is an Earth Scientist at the Joint Global Change Research Institute College Park, MD, and a Research Professor at the University of Maryland, Center for Global Sustainability. Smith's research has focused on long-term socioeconomic scenarios, the interface between socioeconomic systems and the Earth system, and interactions between air pollution and forcing. Smith is co-principal investigator of the Community Earth atmospheric Data System (CEDS) project that produces global historical air pollutant emissions over the industrial era (1750-present). CEDS provides the historical forcing data for Earth system models participating in the Coupled Model Inter-comparison Project and other modeling and analysis efforts around the globe. Smith also works with the Global Change Analysis Model (GCAM), which he and collaborators are using to examine multi-sector interactions between the energy system and air-pollutant emissions from global to regional scales. Smith also contributes to national and international assessment activities, and is a member of hte scientific steering committee for hte Global Emissions InitiAtive (GEIA).