Snow and ice are an important component of the water cycle. Snow stores the precipitation of the cold season and releases it during summer, whereas glaciers can have the same effect over a much longer time horizon. Water from today’s glaciers is the result of the melting of ice that has been accumulated over the last decades to centuries.
With the steady rise in global air temperatures, concerns about future water availability are emerging. During summer, the situation could become critical, especially for regions with limited precipitation. This is because an earlier onset of the melting season will cause the winter snowpack to deplete early in the year, and because the total amount of ice melt is expected to decline considerably due to glacier retreat.
People outside the specialists’ community often approach us with the question: ‘Could it happen that glaciers start to re-advance one day?’ Our usual answer is that yes, glaciers will almost certainly re-advance one day, but that this is likely to be so far into the future to be of hardly any relevance to us. The initiation of a new ice age would require a massively lower greenhouse gas concentration in the atmosphere, and a recent study suggests that anthropogenic emissions will prevent a new glaciation for the next 50,000 years at least. Current glacier extents are so far out of balance with present climate that even if global air temperatures would be stabilised immediately – a highly unrealistic scenario – glaciers would continue to retreat for large parts of the 21st century.
If glacier retreat and its negative consequences are inevitable over the foreseeable future, one may want to ask whether the expected effects could at least be mitigated. In our most recent publication, we addressed this question, and assessed how much of the impact that glacier retreat has on water availability could be offset through a technical solution.
Our basic idea was quite simple: As glacier models predict increasing runoff during winter and spring, we investigated if this additional water could compensate for the water loss expected during summer. Additionally, we assessed whether the construction of new artificial dams, virtually placed at the snout of today’s receding glaciers, would be sufficient for seasonally transferring the water volume. We focused on the Alps, the ‘water tower’ of Europe.
The main result was that the proposed strategy could offset as much as two thirds of the expected changes in summer water availability, and that the potentially installable artificial storage volume is largely in excess of the required one.
So, is the problem solved, and future water availability in dry summer months secured? Unfortunately, the answer is no.
First, we only considered the water yield from the presently glacierised area. For the European Alps, glaciers provide about 5.3 cubic kilometres of water per year (about one and a half times the annual freshwater consumption of the United Kingdom). This is only a fraction of the total water available on the continent. For large-scale water availability, the total amount of precipitation is crucial, and much uncertainty is associated with current precipitation projections. Climate models often even disagree on the direction of the change, thus leaving unanswered whether we should be prepared for a dryer or a wetter future. Improving our capabilities of predicting such changes is crucial and requires investments in the according research.
Second, our analysis only addressed the mitigation that could be achieved in summer. Basically, our approach shifted water from one season to another. This can obviously not compensate for an overall decrease in meltwater. Our results indicate that due to glacier retreat, about 0.7 cubic kilometres of water could be missing from annual supplies in the Alps by the end of the century. Replacing this supply is a challenge that cannot be met by constructing new dams, and efforts for a more efficient water use will be required instead. Trends towards a lower per-capita consumption, as observed in the water use statistics of many European countries, are encouraging in this respect, but signals from fast growing economies are far less reassuring.
Third, our analysis assumed that the future water demand for winter and spring will remain unaltered. This can be questioned. On the one hand, the steady increase in population partly offsets the decreasing per-capita use. On the other hand, keeping the same level of water consumption might be in conflict with specific interests. Hydropower companies operating in high alpine areas, for example, transfer water from the summer months to the winter in order to produce electricity at better market prices. For this particular industry, the expected increase in winter water availability could thus be an appreciated effect. Accounting for the different interests of the many stakeholders involved in water policy issues must be a priority when considering active measures such as the one suggested by our study.
The most important point to us, however, is that even if a technical solution can be found, we should not disregard the necessity of societal change. And this is not only true for the consequences of glacier retreat, but also for many of the most pressing challenges that we will face in the near future, such as climatic change, water availability, biodiversity preservation, food security, or overexploitation of resources.
In our opinion, too much hope is often laid on technologies yet to come. For water management, new dams are hoped to temporarily store water, whilst refined industrial processes or new irrigation infrastructures should reduce water requirements from industry and agriculture. For food security, genetically engineered crops and specifically designed fertilisers are expected to boost yields from cultivated areas. For climate change, carbon sequestration techniques promise to one day remove the greenhouse gases that are currently emitted into the atmosphere. And so on.
Although we examined a technical solution in our study, we are convinced that technology alone won’t be sufficient for addressing all challenges we need to face. Instead, we have to reconsider our actual needs, and the way we deal with resources. Current lifestyles in Europe require about 150 litres of water per day from the tap: are they all necessary? Statistics tell that some countries require much less than that. Is the diet of most western countries really required? In a recent study, the year 2011 was reported to be the first in which the global population counted more obese than underweight adults. Should we keep our demand for mobility as high as today? For the period between 1983 and 2001, the US Department of Transportation reports a 60 per cent increase in the daily distance travelled by car by US citizens.
Propagating western lifestyles at a global level is not a sustainable option. Our planet has limited resources, and no technical solution will ever be able to satisfy a steadily increasing demand. It is surprising and alarming that this trivial consideration is so often disregarded. To us, breaking the ‘growth at all costs’ logic of the present economies is the only way to allow planetary resources to be preserved for the next generations, and to promote fairer opportunities for all individuals. Regulations enforcing a more circular use of resources in a less consumptive economy could be a first step. Yet, increasing the overall awareness that every resource is finite, remains a much-needed, longer-sighted strategy. This awareness will necessarily pass through education and, probably, the questioning of materialism as the only way to well-being. We sometimes dream of a world in which this is recognised soon.