The invention and availability preventing drugs and vaccines avoid and withstand infectious disease successfully; moreover, treatments for the common illness such as cardiovascular disease and pneumonia also have contributed to the reduction of death rates (Francis). Hence, since that medical technology well developed, the average global life expectancy has also increased. According to the publication entitled Global Health and Aging, published by the National Institutes on Aging, most developed countries had population aged 65 or older to rise from 7 percent to 14 percent in last 100 years, and even in the less developed countries are "experiencing a rapid increase in the number and percentage of older people, often within a single generation" (8). Nowadays, humans can live longer and healthier than before around the world, even in some underdeveloped countries. This trend is a contributing factor to overpopulation because the older generation is not dying off as early as they did in the past and babies continue to be born. Therefore, there are more people on the planet at the same time than there have been in previous generations. .
Secondly, advancement in agriculture also contributes to the overpopulation, because its technological revolutions that allow for more food to reach more people. Both the agricultural and industrial revolutions were followed by population booms ("Human Overpopulation"). The agricultural revolution increases food production which means human makes a transition from a hunter-gatherer lifestyle to a farming lifestyle. A writer, Elizabeth Kolbert, wrote an article, post on The New Yorker claimed that in recently years, technological interventions, such as use of pesticides, genetic engineering and fertilizers have supported farmer to grow plants that are resistant to insects and environmental stressors and are therefore able to produce an enormous amount of food ("Head Count").
