Multiple environmental stresses and rapid social change reinforce the need for better evidence – evidence that is robust and the product of interdisciplinary and intersectoral collaboration. 
 The potential benefits to health from sound environmental policies are significant. 
 Human health is a key indicator of sustainable development. We need to monitor changes in human population health in order to evaluate progress on global sustainability.  
  Global health refers to health  issues that transcend  national borders and whose  solutions require international  cooperation. 
 Global health  issues include both the major killers  of the past (malnutrition, infant  mortality and diarrhoeal diseases) and  of the future (cardiovascular disease,  chronic lung disease, cancer and  diabetes). 
 It also includes preventative  activities (targeting populations) and  clinical care (for individuals), as well as  the interrelationships among humans,  domestic animals, wildlife and  ecosystems. 
 Health equity – access  to good health for all – is a central  aspiration of global health, which  is therefore transdisciplinary and  requires scientific evidence beyond  that of the traditional health sciences.