evidence: The massive increase in world population in the 20th century was the fastest in human history. It came on the heels of the Industrial Revolution, and the combination of the two factors led to a huge increase in carbon emissions. The carbon dioxide level in the atmosphere in 1950 was around 300 parts per million, but just under 70 years later, that number had increased to 400 parts per million. This is a huge increase in a geologically minuscule period. During that same time, the world’s population increased by over 5 billion. These two facts are closely related. People need food to survive, and as the world’s population grows, so too does the demand for food. To meet this demand, agricultural development has caused deforestation on a large scale. The shrinking forests are unable to counteract the effects of the increasing carbon emissions, causing temperatures to rise. This, in turn, has caused desertification, especially in the already vulnerable Middle East and North Africa (MENA) region. The resulting loss of arable land means less food production, which threatens to leave millions undernourished. A related problem is water scarcity, caused by increased salinization and the drying up of rivers, lakes, and streams. [...] Earlier this year, the Intergovernmental Panel on Climate Change issued a report that included the following conclusion: "Globally, Gross Domestic Product (GDP) per capita and population growth remained the strongest drivers of CO2 emissions from fossil fuel combustion in the last decade."