170 5. Poverty, disasters, and disease are still challenges today. The gap between rich and poor nations is growing. Half the world's population earns less than $2 a day. Poverty is a complex issue with many causes. Many poor nations owe billions in debt and have little money to spend to improve living conditions. POLITICAL UPHEAVALS, CIVIL WAR, CORRUPTION AND POOR PLANNING INHIBIT EFFORTS TO REDUCE POVERTY. Rapid population growth and urbanization also contribute to poverty.
Natural disasters cause death and destruction around the world. One example is the tsunami in the Indian Ocean in 2004. Other natural disasters include earthquakes, floods, avalanches, droughts, fires, hurricanes, and volcanic eruptions. Natural disasters can cause unsanitary conditions that lead to disease. Global travel makes it possible for diseases to spread quickly. When a disease spreads rapidly, it is called an epidemic. HIV/AIDS is an epidemic that has killed millions. Natural disasters can also cause famine. Wars and problems with food distribution also contribute to famine. Poverty, disasters, and wars have forced many people to become refugees.
International agreements, such as the Universal Declaration of Human Rights and the Helsinki Accords, have tried to guarantee basic human rights around the world. However, human rights abuses continue. Women in both the developed and developing world often lack equal rights. Worldwide, children suffer terrible abuses. In some nations, they are forced to serve as soldiers or slaves. Indigenous people around the world also face discrimination and exploitation.
Industrialization and the world population explosion have caused damages to the environment. Strip mining, chemical pesticides and fertilizers, and oil spills are all environmental threats. Gases from power plants and factories produce acid rain. Pollution from nuclear power plants is another threat. Desertification and deforestation are major problems in certain parts of the world. Deforestation can lead to erosion and is a special threat to the rain forests. One hotly debated issue is global warming. Many scientists believe that Earth's temperature has risen because of gases released during the burning of fossil fuels. Others argue that global warming is due to natural fluctuations in Earth's climate.
5. Compare the two theories about global warming mentioned in the Summary.