What is the biggest global health threat of the 21st century? Is it swine Flu? AIDS? Obesity? According to a group of 18 leading doctors from around the world in a recent letter to the British Medical Journal & Lancet it is climate change. Here are some of the ways that climate change affects human health: 1) Food Supply: Increased temperatures and unpredictable rainfall can reduce crop yields, affect livestock and compromise our food supply. 2) Extreme Weather Events: Climate change may cause more heat waves, cold waves, storms, floods and droughts. This can increase the risk of food and water shortages and water- and food-borne diseases. Heat waves can claim the lives of the weak, and elderly as in Europe’s 2003 summer heat wave which claimed the lives of over 30,000 people. 3) Disease: Many diseases carried by insects such as malaria, and dengue fever thrive in warmer climate conditions and climate changes can prolong and intensify the transmission of these diseases. 4) Air Quality: Warmer temperatures mean a higher frequency of smog which exacerbates respiratory conditions such as asthma and other chronic lung diseases. In recent years the polar bear has become the prominent face of climate change, but we need to refocus on the human faces affected by the changes in our environment. We must emphasize the children, families and communities whose health will be affected by these changes and concentrate less on the polar bears.