(1) Human societies had equally high birthrates and death rates during most of history. But over the past century, population growth in the United States, Japan, and much of Europe slowed dramatically. Demographers developed a hypothesis to explain this shift. According to this hypothesis, these countries have completed the demographic transition, a dramatic change from high birthrates and death rates to low birthrates and death rates. The demographic transition is divided into three stages. (2) To date, the United States, Japan and Europe have completed the demographic transition. Parts of South America, Africa, and Asia, are passing through stage II. (The United States passed through stage II Between 1790 and 1910.) A large part of human population growth is happening in only ten countries, with India and China in the lead. Globally, human population is still growing rapidly, but the rate of growth is slowing down. FuFuttuurree PPooppuullaattiioonn GGrroowwtthh (3) To predict how the world’s population will grow, demographers consider many factors, including the age structure of each country and the effects of diseases on death rates, especially in Africa and parts of Asia. Current projections suggest that by 2050 the world population will reach 9 billion people. Will the human population level out and become stable? This may happen if countries that are currently growing rapidly complete the demographic transition. (4) Current data suggest that global human population will grow more slowly over the next 50 years than it grew over the last 50 years. But because the growth rate will still be higher than zero in 2050, our population will continue to grow. The word shift in Paragraph ((1) is closest in meaning to …………………
Why will the population continue to grow in 2050?