Increased rainfall over extended periods will mainly lead to river flooding, while short, intense cloudbursts can cause pluvial floods. Due to changing climate, many parts of the world are already facing more frequent severe and longer lasting droughts. Droughts often have knock on effects, for example on agriculture, forestry, water resources and biodiversity. They reduce water levels in rivers and ground water, stunt tree and crop growth. Further human, animal and plant health are also threatened by climate change. While climate change may not introduce new health hazards, it will worsen and amplify existing one.