You don’t have to go back to biblical times to find a more verdant Iraq. Well into the 20th century, the southern city of Basra was known as the “Venice of the East” for its canals, plied by gondola-like boats that threaded through residential neighborhoods.

Indeed, for much of its history, the Fertile Crescent — often defined as including areas of modern-day Iraq, Israel, Lebanon, Syria, Turkey, Iran, the West Bank and Gaza — did not lack for water, inspiring centuries of artists and writers who depicted the region as a lush ancient land. Spring floods were common, and rice, one of the most water-intensive crops in the world, was grown for more than 2,000 years.

But now nearly 40 percent of Iraq, an area roughly the size of Florida, has been overtaken by blowing desert sands that claim tens of thousands of acres of arable land every year.

Climate change and desertification are to blame, scientists say. So are weak governance and the continued reliance on wasteful irrigation techniques that date back millenniums to Sumerian times.

A tug of war over water — similar to the struggles over the Colorado River in the United States, the Mekong in Southeast Asiaand the Nile in northern Africa — has also intensified water shortages for tens of millions of people across the region.

Another culprit is common to large regions of the world: a growing population whose water demands continue to rise, both because of sheer numbers and, in many places, higher living standards, increasing individual consumption.

Here in Iraq, the fallout is everywhere, fraying society, spurring deadly clashes between villages, displacing thousands of people every year, emboldening extremists and leaving ever more land looking like a barren moonscape.