Our planet is currently being challenged by dramatic changes to earth and human systems under the influence of climate change and variability. These include changes of population and environmental dynamics that impacts human health. Thus, climate change is considered the biggest threat to human health in the 21st century. Health impacts can be direct typically related to extreme weather events; indirect with linkages to climate change induced environmental alterations and damage or in relation to displacement, conflict and social disruption. This presentation provides a series of examples of changes of environmental and social determinants of health with negative or positive health impacts. These include impacts on communicable diseases, non-communicable diseases and mental health of importance in particular in vulnerable urban and rural settings as well as among sensitive community groups exposed to variations in temperature and precipitation patterns.

Infectious diseases have a specific, ethiological cause, e.g. a microbe such as tuberculosis caused by Mycobacterium tuberculosis. However, most people exposed to TB does not develop the disease. What determines this may be poverty, weakening of the person by other diseases or smoking and alcohol. So-called life-style diseases are (also) determined by the way you live, and include prevalent non-communicable diseases such as type 2 diabetes and cardio-vascular diseases, but besides of risk factors such as smoking and drinking or over-eating, the living conditions matter equally and sometimes more. The environment, climate changes, urbanization, socio-economic factors all impact health and disease. When an individual grows older, patterns of his/her diseases changes: the same applies when a society grows ‘older’.

Previously infectious diseases previously caused the majority of ill-health and premature death globally, but in high- and middle-income countries during the 20.th century infectious diseases – with the exception of HIV – declined. Introduction of hygiene and discovery of microbes and later vaccines an antibiotics contributed to the decline, but changing living conditions with better housing, nutrition, water and sanitation were the main drivers of infectious diseases’ decline.

In this presentation the global burden of diseases – deaths as well as disabilities – jointly named DALYs – is presented and differences and similarities between lo-, middle-, and high-income countries presently and over time are presented. The strict division between non-communicable and communicable (infectious) diseases is also challenged, and propositions on how to manage them jointly are given. The double burden of NCD+overnutrition and CD+undernutrition in societies in fast transition is presented. The present vs. the expected global burden of diseases by the year 2030 are also introduced.