The earth is getting hotter, and scientists overwhelmingly agree that temperatures will keep going up if we fail to dramatically reduce global warming pollution. The consequences of a warmer world range from dirtier air and water to more severe floods and droughts to a rise in human health problems and the spread of tropical illnesses. Learn what's in store for our planet over the coming century.As earth's thermostat climbs, threats to human health will mount, from tropical diseases to an increase in allergies and asthma.