Weather forecast: More permanent droughts

Green transition 11 December 2015 Søren Hvilshøj

Much less rain and snow has become the norm in many areas around the world. The latest studies conclude that California will be among the regions hardest hit by water scarcity. We may not be able to control the weather, but with engineering we can control how water flows.

8 min

As reservoirs run dry, crops are abandoned and cities work to meet mandatory water cuts, drought-weary Californians are counting on a saviour from the Pacific: El Niño. The periodical warming of the tropical part of the ocean could well bring heavy precipitation to parts of California this winter (2015-16), but it will not change the new climate reality that confronts the state.

This is the conclusion reached by a prominent group of scientists, headed by Alton Park Williams of Lamont-Doherty Earth Observatory, Columbia University, whose findings were published recently in the scientific journal Geophysical Research Letters.

Droughts have always plagued California – as so compellingly depicted in works like John Steinbeck’s book ‘Grapes of Wrath’ or Roman Polanski’s film ‘Chinatown’.

But the UN Climate Panel and countless other scientists warn that climate change will worsen droughts in drought-prone regions, even rendering some areas permanently arid.

Another recent study on California – published in the Proceedings of the National  Academy of Sciences (PNAS) – shows that global warming has doubled the odds of the hot, dry conditions that are intensifying and prolonging the current drought. This drought now holds the record not only for lowest precipitation and highest temperature but also for the lowest spring snowpack in the Sierra Nevada in at least 500 years.

“These changing odds make it much more likely that similar conditions will occur again, exacerbating other stresses on agriculture, ecosystems and people,” conclude the scientists behind the PNAS study, Noah S. Diffenbaugh, an associate professor of earth system science at Stanford University, and Christopher B. Field, Director of the Department of Global Ecology at the Carnegie Institution for Science.

The scientists unanimously recommend that governments enhance the climate resilience of their countries and build protection for the future.

Collecting rainwater

But what can we do to change the weather if rain dancing or cloud-busting are improbable options?

Not much. But experts point out that we can affect how water flows.

In fact, saving water would be the most efficient means of increasing the water supply, especially if the agro  industry lowered the tremendous amounts of water it consumes. For example, California currently produces more than 80% of the world’s almonds, and each little nut takes  four litres of water to grow.

However, water conservation is much more politically controversial in the USA than in Europe, and increasing or introducing other restrictive measures would be likely to result in legal action.

Therefore, you have to resort to collecting rainwater, for example.

Having visited California this autumn (2015), I have seen the almost empty reservoirs and other signs of the drought firsthand. American experts are tackling the problem, but I believe Scandinavian experts also have a lot to offer.

Scandinavian companies have gained a lot of experience collecting and using surface water rather than letting it run off in sewers – as is the tradition in the USA.

Ramboll, for example, has carried out much of the Danish National Groundwater Mapping Programme, an initiative encompassing multidisciplinary hydrogeological projects.

So, first, we can conduct 3D-surveys to identify where collecting surface water is cost-effective. We understand the geology and how to measure and prevent contamination risks. Second, we’ve done many holistic projects in Sweden, Finland, Romania and now also Dubai, where rainwater from roads or big parking lots is collected and filtered, so it ends up as potable groundwater.

And prominent politicians in California are listening:

“As chair of the California State Senate’s Natural Resources and Water Committee, I was quite interested in tapping Ramboll’s expertise in water and energy sustainability,” says senator Fran Pavley, who visited Ramboll’s Head Office in Copenhagen this September (2015).

“California is facing a fourth year of record drought, and our delegation benefited greatly from what we learned in Copenhagen about the interplay between smart infrastructure investment and high-tech conservation practices. The combination can help us adapt to climate changes,” the Senator observes.