PRODUCTION of plant-based illicit drugs has surged in recent years, according to the UN Office on Drugs and Crime. The world’s output of opium rose by 65% in 2017, reaching its highest level since records began. Of the 10,500 tonnes made last year, 9,000 came from Afghanistan, a country wracked by violent conflict and rural poverty. Global cocaine manufacturing also reached a record high in 2016 (the latest year for which data are available), rising by 25% year on year to 1,410 tonnes. More than half of this amount originated in Colombia.

The White House Office of National Drug Control Policy published estimates for production of cocaine and cultivation of coca, the raw material for cocaine, in Colombia last year. It said that production rose from 772 tonnes in 2016 to 921 tonnes last year. The area under cultivation increased by 11%, to 209,000 hectares.

The increased cultivation of coca in Colombia defied expectations that the government’s peace deal with the FARC guerrillas, who relied financially on drug trafficking, would curtail the cocaine trade. One explanation is a textbook example of the law of unintended consequences. The peace agreement required the government to make payments to coca farmers who switched to growing other crops. This wound up creating a perverse incentive for people to start planting coca, so they could receive compensation later on for giving it up. The government also scaled back its aerial crop-spraying programme as peace talks progressed, which allowed cultivation to expand. As the FARC became less active, and eventually disarmed, other armed groups took over the cocaine trade.

In Afghanistan, poppy cultivation rose following the American invasion in 2001. After a dip around 2010, it has reached new record highs. The United States has spent more than $10bn on anti-drug efforts in the country, mainly on setting up eradication teams, giving cash to Afghan peasants to grow wheat instead of poppies and rewarding local politicians from areas where opium production fell. However, rather than reducing poppy output, this campaign seems to have merely relocated opium production to areas controlled by the Taliban—enriching the very group America has sought desperately to defeat.