Founded in 1992, SPARC (Stratosphere-troposphere Processes And their Role in Climate) has coordinated high-level research activities related to understanding Earth system processes for over two decades. In order to broaden the range of topics to the whole atmosphere, it was decided by the SPARC Scientific Steering Group to move to a new era of the project now called APARC (Atmosphere Processes And their Role in Climate) starting on January 1, 2024.

What is APARC?

APARC is a core project of the World Climate Research Programme (WCRP). More specifically, APARC promotes and facilitates cutting-edge international research activities on how chemical and physical processes in the atmosphere interact with climate and climate change.

APARC activities are organised under three overarching themes and result from an integration of process studies, observations, and modelling. Research is largely bottom-up driven and contributes significantly to international assessments, such as the assessments of ozone depletion by the World Meteorological Organisation (WMO) and United Nations Environmental Programme (UNEP), as well as the climate assessments of the Intergovernmental Panel on Climate Change (IPCC). APARC products include scientific assessment reportsjournal publicationsnewsletters, and datasets.

Much of the science APARC is coordinating relates to the WCRP Grand Challenges (GC), particularly the GCs on Clouds, Circulation and Climate SensitivityNear-term Climate PredictionClimate Extremes, and Carbon Feedbacks in the Climate System. Grand Challenges are both highly specific and highly focused, identifying specific barriers preventing progress in a critical area of climate science. They enable the development of targeted research efforts with the likelihood of significant progress over 5 to 10 years.

The Scientific Steering Group (SSG) provides leadership for APARC and represents a broad spectrum of disciplines and nationalities, including both junior and senior scientists. The APARC SSG is supported by the APARC Office and activity leaders. All scientists involved in APARC initiatives work on a voluntary basis and often spend time and resources outside regular office hours on APARC activities. The continuing success of APARC relies on the essential contributions of this community.

What does APARC do?

Scientific research coordination: APARC brings together the world’s experts to address key questions in atmospheric and climate research.

APARC workshops, meetings, and general assemblies: To facilitate high-level science, APARC organises many workshops and meetings related to APARC activities and themes. The APARC General Assemblies (APARC GAs) are held approximately every four years and are key events in the APARC calendar, bringing together scientists from the international community to discuss APARC-related research.

APARC science: SPARC/APARC is well known for its comprehensive scientific reports, which assess current knowledge and understanding on topics within APARC research themes.  These reports are strictly peer-reviewed and of high scientific quality, having been widely cited and influential in the WMO/UNEP Ozone Assessments and IPCC Assessments. Results from APARC activities are also often published in special issues of scientific journals.

APARC communication: APARC’s biannual newsletters are well cited in peer-reviewed publications reflecting their high scientific quality and visibility. They include:  (i) reports of the annual APARC Scientific Steering Group meetings as well as WCRP Joint Steering Committee meetings and other activities related to WCRP;  (ii) reports of scientific workshops, related meetings, and activities supported by APARC;  (iii) summary articles on new research activities, measurement campaigns, and programmes related to APARC. APARC also communicates regularly with the community through its eNews bulletins.