If we all ate more vegetables and less meat, and cut down on bananas, chocolate and coffee, we could free up significant areas of land for restoration and save hundreds of the world’s species from extinction, finds a new Cambridge study.

A recent study published in National Science Review has introduced a policy-specific assessment framework featuring a novel Synergy Index, designed to uncover how air pollution control and carbon mitigation can move in harmony or fall out of step. Drawing on China’s on-road transportation sector as a case study, the research quantifies both the realized and untapped synergies in reducing greenhouse gases (GHGs) and improving air quality. The findings paint a compelling picture: from 2010 to 2020, China’s on-road transportation emission control policies achieved lower GHG emissions, cleaner air, and substantial public health benefits. However, behind this progress lies an unexpected finding showing that policy synergies have been weakening, highlighting the urgency of robust structural transitions to maintain long-term carbon and air-pollution co-control, to advance a sustainable pathway toward the Sustainable Development Goals, and to fullfil the newly announced NDC target.