Autumn will be hotter and drier than it should be. The drought is here to stay and the water war with Spain is just beginning

“Hot” and “dry”. These expressions accompany the monthly bulletins of the Instituto Português do Mar e da Atmosfera (IPMA) for practically every month of the year 2022, often accompanied by an alarming “extremely”. In the first eight months, March was the only one that registered normal temperature and precipitation values ​​- the reference is the period between 1971 and 2000 -, which shows major anomalies in a year that was, almost always, hot and dry. And in autumn, what will it be like?

The new season of the year starts this Friday and, according to IPMA forecasts, there will be a combination of positive anomaly in temperature and negative in precipitation. The same is to say that it will be hotter than expected and it will rain less than normal, following the trend of the year, and that it will extend to the rest of 2022. The institute’s long-term forecast indicates that these anomalies will continue in October and November, months that will also be hotter and drier than normal.

“In the average monthly air temperature, a positive anomaly is expected over the mainland, 0.25 degrees to 1 degree, for the months of October and November”, says the IPMA note.

Source: IPMA

Note: the values ​​are compared with the climatic normals of 1971-2000

New drought in spring?

These figures help to explain why Portugal has been experiencing a drought for several months. We are currently living between a severe drought (60.4% of the territory) and extreme drought (39.6%), the only two scenarios that the country has known since July, in a year that did not have values ​​considered normal in any part of the mainland. . September was even a month of “significant amelioration” of the drought situation, but the scenario is far from over. Incidentally, the last time this happened was in the Minho region and near Serra da Estrela, in 2021.

The professor of Meteorology at the Faculty of Sciences of the University of Lisbon, Ricardo Trigo, explains that these values ​​are in line with what experts have been predicting for two decades, saying that the problem is not only in the fact that it rains less, but also in the greater evaporation of water from soils. Basically, it’s as if climate change contributes to drought in two different ways.

“The PDSI [índice que mede a situação de seca] takes into account precipitation, but also what the soil loses. In the last three decades, the temperature has increased significantly in Portugal. The fact that it rains less increases the probability of water stress, but the heat waves have increased more in relation to the decrease in precipitation”, he says. In practice, evaporation means that there is “less water in the soils, rivers and dams “.

Outlining a scenario for what is to come, Ricardo Trigo has no doubts: “Either it rains much above average in the coming months, or at the end of spring we will have the country again in a very leveraged drought”. And even if that rain does come, it will hardly be in the best way, as our best chance of avoiding a short-term drought is new phenomena like Storm Danielle.

“There will have to be successive storms, because moderate and prolonged rains are less expected, especially in the south of the country”, he says, noting that this scenario is far from ideal, not least because “to avoid drought, a set of days with moderate rainfall, which is better for dams, agriculture”. In the background, “little and moderate rain makes more recharge of soils and aquifers”.

And if the lower occurrence of moderate and prolonged rainfall is an increasingly visible scenario, climate change is largely responsible. Ricardo Trigo says that for each degree that the average temperature increases in a given period, there is 6% to 7% more water in the atmosphere. Now, that water will eventually have to fall, and it does so in the form of a storm. In the case of Storm Danielle, for example, “in much of Portugal, it rained at or above the average of September in just three days.” If this seems like good news at first, look at the example of Serra da Estrela, which was heavily affected by fires this summer: “When large areas burn, when the rains come, there is no capacity to retain water”. That’s why landslides happen.

“It may rain a little less when we count at the end of the year, but the rain tends to fall more concentrated”, stresses the Meteorology professor, pointing out that “any mechanism brings more water than 40 or 50 years ago”. “Precipitation is higher, more intense, which also causes soil erosion”, precisely as happened in the lands adjacent to the largest Portuguese mountain range.

an announced war

This scenario does not only affect Portugal, but all of Europe. Spain is experiencing one of the worst droughts in history, which is leading to desperate situations. For this reason, farmers who work close to the border decided to come together this week in León, coming from Salamanca or Zamora, to ask for the volume of water destined for Portugal to be stopped, which was agreed under the terms of the Convention on Reservoir. It has long been warned that climate change is moving climate systems to the north, which will slowly make the Iberian Peninsula more like the Sahara. Being part of the instability in that region of Africa related to the lack of water, is this war coming here?

The chairman of the board of the Confederação dos Agricultores de Portugal tells CNN Portugal that “there are still conditions for the flows to have to come from Spain to Portugal”. Even so, Eduardo Oliveira e Sousa warns: “The wolf, which is Spain, is right up there. If they have their hands on the tap, on the day the water starts to run out, I have no doubt, they’ll turn off the tap” .

The reason is that Spain’s water reserve is only a third of its capacity – it has 18,810 cubic hectometers of water when the storage capacity reaches 56,136, according to the most recent Hydrological Bulletin. A clear sign of worsening, since this value was, at the same time in 2021, 22,646, with the 10-year average still set at 28,656 hectometers. In Portugal, this storage capacity is more controlled – around 53%.

Source: Portuguese Environment Agency (Portugal) and Hydrological Bulletin (Spain)

But the real problem may not even have started yet. The anomaly forecasts made for Portugal extend to Spain, and even in a potentially more serious scenario – the European forecast system points to an even darker spot for the center of the Iberian Peninsula in the month of October, which means a temperature anomaly. even bigger there. Something corroborated by the State Meteorological Agency of Spain, and all after the hottest summer in the last 61 years.

Spanish farmers know this, which is why they decided to mobilize with slogans such as “no to the transfer [de água] to Portugal”. In practice, what they want is to prevent the sending of 400 hectometers of water through the Douro River, one of the four rivers shared between the countries, and which are part of the Albufeira Convention. This volume of water must be sent to Portugal until 30 September, as part of the agreement that provides for the sharing of 570 hectometres of water during the summer, which led the approximately 3,000 Spanish farmers present in Leão to shout “if they take our water, they take our bread”.

If the varnish has already broken in the Douro, the same could happen in the Tagus, where in the region of Cáceres there is already pressure so that the amount of water to which Portugal is entitled is not released. The problem, experts say, is that the levels of the agreement are already outdated. When it was signed in 1998, the Albufeira Convention provided for an irrigation area of ​​100,000 hectares in Leão. Today, throughout Spain, there are already 3.8 million hectares of irrigated land, which contrasts with the capacity of its reservoirs: Guadalquivir is at 22%, Guadiana at 24.5%, Tejo at 37.7%, Douro at 37.8% and Ebro at 43.3%.

“They have less water than us, they just did their homework. They store 70% or 80% of the run-off they have, we store 20%”, says Eduardo Oliveira e Sousa.

Portuguese farmers on the Tagus understand the Spanish attitude, not least because, as they say, the water resources to which Portugal is entitled end up being misused most of the time. Therefore, they tell CNN Portugal, better management is needed: “We need our Government to understand us and that there is a change in the management of water resources”, says Mário Antunes, from Agromais.

This same management of water resources is pointed out by Ricardo Trigo as one of the keys. The specialist recalls that more than 60% of the water used in the Iberian Peninsula is for agriculture, noting that “there are already ways” to make better use of water, such as drip systems.

“If we invest less in golf courses and in a certain type of agriculture, we will save water. If we insist on a very demanding agriculture, it is difficult to guarantee water for everyone”, he says.

Even so, he says, the war for water could become something seasonal: “in a year when it rains above average people forget that”, but only until the next drought, when the problem will reappear.

Therefore, underlines the professor of Meteorology, a better bet is needed on technology that allows a better use of water, not least because “there is a lot of water loss in the channels, in the pipes, there is a large percentage of water lost”.