Non-CO2 greenhouse gases: the underrepresented, complex side of the climate challenge

When it comes to mitigating climate change, the focus tends towards carbon dioxide (CO2) emissions. However, human-induced emissions of non-CO2 greenhouse gases (GHGs) are important contributors to global warming. These include methane (CH4), nitrous oxide (N2O), fluorinated greenhouse gases (HFCs, PFCs and SF6) and ozone depleting substances. Other non-CO2 emissions, such as aerosols (e.g. black carbon (BC)) and pollutants that function as aerosol or GHG precursors, contribute to changes in the atmosphere’s energy balance. This editorial overview introduces a Special Issue (SI) of Journal of Integrative Environmental Sciences that includes contributions from the 8 Non-CO2 Greenhouse Gas Symposium (NCGG8), which took place in Amsterdam, June 10–15, 2019. NCGG8 covered recent scientific advancements in understanding non-CO2 sources, climate implications and mitigation challenges. The articles in this special issue highlight some of outcomes of these discussions.