Better understanding of the impacts of global change (such as changes in anthropogenic emissions, climate, land use and land cover etc.) on atmospheric chemistry and air quality as well as the interactions between them is an emerging priority for research and policy. Both regional and global climate change are highly interrelated with atmospheric chemistry. Climate change could have large impacts on atmospheric chemistry and air quality by changing a suite of meteorological variables which can affect the emissions, transport, chemistry, and deposition of various species. The perturbations to atmospheric chemistry and composition can also affect climate in important and complicated ways. The changes in abundance and distributions of many species can either directly or indirectly influence the climate.
We invite presentations that use modeling, field, laboratory and satellite approaches to better understand important mechanisms for chemistry-climate interactions on global and regional scales and for past, present and future climates.

Another topic to cover in this session is on the appropriate and useful metrics to inform climate and environmental policies and assessments.
Metrics can be generally defined as a quantitative measure of climatic and environmental effect or impact used to evaluate mitigation measures, the state of the environment, or risk to human health or ecosystems. An emission metric in the climate context is an index to designate relative weights of the emissions of different greenhouse gases and related components in climate and environmental policies and assessments. The Global Warming Potential (GWP) and the Global Temperature change Potential (GTP) are currently most commonly used, while a number of alternative metrics have been proposed and are being developed. An air quality metric is, on the other hand, an indicator of the state of air pollution levels (often a legally binding target value) typically designed to protect human health. As interest in the role of air pollutants on climate increases, the desire to compare climate gases with so called 'short-lived climate forcing pollutant' has added an extra dimension of complexity to the issue of metrics. Challenges include: i) to clarify differences in economic costs arising from the choice of metrics, ii) to explore regional/local dimensions, iii) to determine effective metrics to make use of co-benefits for air pollution and climate change mitigation while avoiding trade-offs, iv) to understand political feasibility to implement new metrics. The body of relevant literature has grown rapidly over the past few years. The policy side has an increasing interest in new developments. To keep up with the challenges the session aims to cover studies in the areas of metrics.