The environment poses a constant threat to people. At any moment a natural disaster such as a hurricane, tsunami, or earthquake could cause devastating property damage, injury, and death. In the last century, humans have made the environment more dangerous by polluting the air and water, cutting down forests, and depleting important natural resources. In recent years, environmental agencies have acknowledged that carbon dioxide emissions have created ongoing changes in the global climate. Climate change would make temperatures around the world more extreme more often and could give rise to floods and droughts. In decades to come, these changes will impact all aspects of human activities and influence the welfare and economic well-being of people throughout the globe.