How can we protect water?

Johannes Cullmann I think it’s basically a good thing that the media have become attentive to the topic of water, because the entire debate about sustainability and resilience is strongly connected to water. About 80 percent of all natural disasters are related to water. Climate change is always a process of water change as well. Our societal and economic resilience also depends on water. How can we continue to engage in agriculture? Who is suffering the greatest long-term damage as a result of hydrological changes? Unfortunately, the media generally focus on spectacular events. These are unavoidable, and they will increase in the next 60 to 100 years. But droughts and floods are only one part of the overall picture.

At the causes that underlie these catastrophes—and at the consequences that ensue. First of all, we need to slow down the water cycle. As a result of human beings’ shaping of our landscape, the water cycle has been accelerated more and more by construction measures. That started to happen as long ago as the Roman Empire. For a long time, we’ve been trying to keep water away from our direct surroundings, either because we’re afraid of floods or because we want to use the land for agriculture, for example. When there are periods of no rain, the increased rate of drainage heightens the risk of droughts. At the same time, flooding situations are dangerously exacerbated because too much water is flowing at once to the same point.

The second important point is that we need to reintroduce more water into our overall system. With the help of satellites, the US-German space mission Grace is monitoring the places where we are losing freshwater all over the globe. To a large extent, this is in the form of snow and ice, which are melting and flowing into the oceans. But this is also happening in warmer regions where there is no snow and ice, such as Brazil and parts of the USA. Here we are losing groundwater because agriculture is expanding without any regard for the natural resources. In Germany as well, the amount of water that is lost from our system every year is greater than the amount of water that Germans drink. All of these factors thus contribute to the proportion of the rise in the sea level that is not due to thermal expansion, which is defined as the expansion of the ocean water that already exists. We need to cre-ate additional reservoirs in order to compensate for these losses, whether it’s through biosystems and in the groundwater or by means of new infrastructure.

Because it still does not represent an urgent problem for most people. The ozone hole seemed directly dangerous to people because they were afraid of getting skin cancer. People are at least vaguely aware of the fact that climate change is an existential issue affecting their future. We still haven’t reached that point with regard to water. For most people, water is still affordable and available in practically unlimited quantities. But here we’re ignoring the fact that our water consumption far exceeds the amount that comes out of our faucets at home every day. Our total consumption is many times larger if we look at how much water is contained in all the food and other goods that we consume. This is what we call our water footprint.

For example, we have to provide people with more information about the conditions under which the inexpensive roses we buy in a discount store are grown in Kenya. The water that is needed for these roses is not available to the local population. We have to explain that the production of half a pound of butter requires about 1,400 liters of water, and that margarine may be a better alternative. We shouldn’t lay down any rules about who can consume what and when, but everyone ought to know what consequences result from their behavior.

We can certainly achieve a great deal through subsidies and taxes—for example, if the government generally supports processes in which water is reused. That could also have an effect on municipal sewage treatment plants, most of which have until now simply channeled the purified water into rivers. The purified water could also be used to reirrigate land or replenish groundwater—in other words, to slow down the water cycle and create reservoirs. No municipality does that of its own accord, because it costs more than the practices that prevail today. The difference in costs has to be offset in financial terms.

You’re right. There should be a global agreement to re-evaluate water as an economic commodity. At the same time, we need international agreements to prevent consumers from switching to products from neighboring countries where water is cheaper or even free of charge. However, making water more expensive across the board without enacting reasonable regulations would be dangerous, because this always affects the poorest people rather than the large-volume consumers. The situation for carbon dioxide is different. If you increase the price of CO₂, you’re not putting a dis-proportionate burden on lower-income groups. 

Together with the UN Climate Secretariat, in 1992 we succeeded in installing a mechanism in which all the countries of the world work together to limit global warming. The most important result of that was the Paris Agreement of 2015, in which 195 states committed themselves to limit climate change and restructure the global economy in climate-friendly ways. At the UN Water Conference this spring, the participants launched a process that will lead, among other things, to a committee in which the UN member states talk with one another and develop guidelines. However, we clearly cannot once again take 23 years to reach a consensus, as we did in the case of the climate agreement.