Problems of the world economy

Some economic problems affect all states and can be solved only together. War sets the economy back by decades, and military spending takes money that could go to education, health and production. Economic activity pollutes air, water and soil and changes the climate; the Paris Agreement adopted within the UN in 2015 aims to keep global warming well below 2 °C above pre-industrial levels, and to 1.5 °C if possible (the book’s figure of 175 signatory states is outdated: today almost every country in the world is a party). Oil, gas and coal are limited and unevenly distributed, so alternative sources such as solar, wind and hydro energy and saving energy are growing in importance. The gap between rich and poor countries is large: a big share of income goes to relatively few people, and the poverty line is set by organisations such as the World Bank and revised from time to time. Causes of hunger are low income, drought, conflicts and supply problems; Malthus predicted that population grows fast and food slowly, but this prediction did not fully come true because yields and technology grew, though distribution and resource problems remain.