The joint efforts of Cape Town's residents continue to push back the arrival of Day Zero, which was originally set for early next month but now might not happen at all this year. If we wish to continue to foster this sort of co-operative behaviour, it's crucial that we signal to citizens that their communal efforts are working.
This is the lesson from the field of behavioural economics, which tells us that people will continue to rally around a public good - like conserving water - if they believe they are working together to achieve a common goal. But if they believe others are not co-operating, it will undermine trust and trigger selfish hoarding behaviour that will lead to overuse of the remaining water. And when the taps run dry for one, they run dry for all.
Last month Capetonians were asked to ration their daily water use to just 50 litres per person. They were also told that Day Zero was imminent: an emergency measure that the city would take, should the dams drop to the last usable 13.5%, that would mean cutting off running water to homes and businesses. Critical services like hospitals would receive running water, but residents would need to collect a daily ration of 25 litres per person from communal distribution points around the city.
In spite of the appearance of panic and finger-pointing about wasteful water use in Cape Town in response to these announcements, our analysis of water use across the city over the past four years indicates that this apparently divided city is showing unprecedented levels of co-operation. Capetonians have reduced their water use by almost 50% in this time; and richer households have brought their use down to the same levels of poorer households, who have little room to reduce their already low consumption rates.Our team of behavioural economists at the Environmental Policy Research Unit recently did an analysis of water use across 400,000 free-standing households to see how people had responded to the various interventions introduced by the municipality: water restrictions, media campaigns, dramatic tariff increases and interventions by the mayor to target high consumers.
Our team also worked with the city to run a series of "behavioural nudges" to encourage voluntarily water-wise behaviour among residents, for example, sending targeted messages comparing a household's consumption to the average consumption in their neighbourhood.
Capetonians have responded remarkably well: residential water use dropped by nearly 50% in just three years, from 540 litres per household per day in January 2015 to 280 litres in January this year.
As restrictions tightened, people have worked harder to meet the city's targets. Since the introduction of the recommended consumption of 10.5 kilolitres a month or less, per household, in July last year, on average 63% of households were reaching that target. Even before the new recommendation of 6kilolitres per household came into effect last month, 30% of households were already reaching this target.
Media reports might suggest that there has been a great deal of finger-pointing as people blame one another for wasteful water use, noncompliance and apparent free-riding. But our analysis tells a different story, one that shows just how much the drought has brought Capetonians together, rallying them around this common cause.Four years ago, water use across households in different income levels was considerably different: richer households were drawing much greater volumes from the municipal system than poorer households were. But in recent months, we've seen a dramatic change in consumption, particularly among the higher-income households, while lower-income groups, who don't have as much scope to cut their use further, have always had rather low levels of water consumption.
This reduction is partly explained by the fact that wealthier households are able to move partially off municipal supply, through drilling boreholes and well points, and investing in rainwater tanks, which has helped push Day Zero back.
Behavioural economics theory warns us that we need to continue to foster the belief that the joint efforts of all are helping to avert Day Zero.
Behavioural economics theory tells us that we need to signal to citizens that the joint efforts of all are helping to avert Day Zero. If people start to believe the blame game that dominates the media now, cooperation will break down and people will stop conserving water and threaten this common resource pool.
Professor Visser is a behavioural economist at the University of Cape Town's School of Economics. Additional research by Johanna Brühl, behavioural economist and researcher with the Environmental Policy Research Unit at the UCT School of Economics...