The wave of protests known as the Arab Spring did not take long to arrive in Yemen after the Tunisian Revolution. Yemen was a poor country with a government widely acknowledged to be corrupt, with a large amount of weapons in private hands. By 2011, the country was already facing challenges from al Qaeda-linked militants and separatists in the south and Zaydi Shia rebels in the north. Yemen had only been unified since 1990, and deep divisions persisted between the north and south.
Yemen's political instability has been compounded and partly caused by the severe ecological crisis in the country. The average Yemeni has access to only 140 cubic meters of water per year for all uses, (101 gallons per day) while the Middle Eastern average is 1000 m3/yr, and the internationally defined threshold for water stress is 1700 cubic meters per year. Yemen's groundwater is the main source of water in the country but the water tables have dropped severely leaving the country without a viable source of water. For example, in Sana'a, the water table was 30 meters below surface in the 1970s but had dropped to 1200 meters below surface by 2012. The groundwater has not been regulated by Yemen's governments. Even before the revolution, Yemen's water situation had been described as increasingly dire by experts who worried that Yemen would be the "first country to run out of water". Agriculture in Yemen takes up about 90% of water in Yemen even though it only generates 6% of GDP - however a large portion of Yemenis are dependent on small-scale subsistence agriculture. Half of agricultural water in Yemen is used to grow khat, a narcotic that most Yemenis chew. This means that in such a water-scarce country as Yemen, where half the population is food-insecure, 45% of the water withdrawn from the ever-depleting aquifers is used to grow a crop that feeds nobody.
This water insecurity has a direct impact on political stability. Outsiders hear most about the proxy war between factions supported by other countries, but according to the Yemeni newspaper Al-Thawra, 70% to 80% of conflicts in the country's rural regions are water-related. The country's Interior Ministry has estimated that across the country, water and land related disputes kill 4,000 people a year - more than terrorism. In Al-Jawf Governorate, a dispute over a well's placement has led to a blood feud that has continued for more than 30 years In 2007, Yemen's minister of Water and Natural Resources suggested that the Sana'a might have to be evacuated if it runs out of water. Although the government was unable to move the capital in an orderly and peaceful way, the war and political crisis has rendered Sana'a and most of Yemen into a battleground that people have been forced to flee.
Additional environmental catastrophes have battered Yemen as the war has progressed. In late 2015, two historic cyclones struck the country. The first of these, Cyclone Chapala, struck the island of Socotra before hitting the port of Mukalla on Yemen's south coast, where it caused catastrophic flash flooding. This storm, combined with the following Cyclone Megh, left enough moisture in the soil for locusts to breed. These locusts can fly 100 miles in a day and destroy any crop they encounter.