Spanish road network destroyed by climate change

By 2050 the maximum and minimum temperatures will show more extreme values, the number of heat waves will double and the number of intense rainfall events will increase, most likely evoking floods. All of these climate changes cause problems for infrastructure. The ground transportation network in Spain is not generally adapted to the forthcoming impacts due to climate change, the road conditions are highly sensitive to the evolution of the maximum and minimum temperatures. CLARITY is working with key stakeholders of Spanish companies as Acciona to provide essential information and strategies how to face this problem. Within its project CLARITY wants to adapt 26,038 km of the Spanish highways and railways to future impacts due to climate change.

Starting with some facts, the Spanish road network includes more than 2,000 km of toll motorways, almost 9,000 km of free motorways and more than 14,000 km of conventional one-way roads. Around ten percent of the total network is composed of toll highways, which are managed by companies as Acciona. 3.6% of the roads are concessions to companies for the conditioning, maintenance and operation.


Spanish managers and users already worked on the project ‘Needs to adapt to climate change of the Spanish transport infrastructures backbone network’, in terms of planning, design, construction, maintenance and exploitation. The Spanish Meteorological Agency (AEMet, Ministry of Environment) has already developed a collection of climate change regionalized scenarios called PNACC (Plan Nacional de Adaptación al Cambio Climático).

CLARITY works together with MeteoGRID, Acciona and CEDEX. CLARITY wants to adapt a subset of the Spanish highways and railways to future impacts due to climate change. The selected roads are of national ownership, in total 26,038 km, representing 15.7% of the Spanish network. And they actually include 3,143 km of the high-speed train network (AVE).

Detailed studies need to be tailored to the extension of some relevant roads, in particular the important transport axis connecting Madrid and Barcelona, for which Acciona is the operator. This four-lane highway section is 73 km long and provides a good example of the network conditions in central Spain, which eventually can be extrapolated to others.


The emission scenarios in terms of climate change for the horizons of 2050 and 2100 show the following facts:

  • The average air temperature will increase about 2ºC in summer and 1.2ºC in winter.
  • The maximum and minimum temperatures will show more extreme values and the variation will be higher than for average temperature.
  • The number of frost days will be reduced.
  • The daily thermal oscillation will be broader.
  • It is expected that around the next mid-century the number of heat waves will double.
  • The relative humidity will generally diminish by 5%.
  • Total cloudiness will be reduced for all regions, with the exception of those in the Northeast of Spain.
  • Annual accumulated precipitation will decrease in all regions: about 5% in the North and in the East, and around 10% in the South and in the West.
  • The number of intense rainfall events will increase, most likely evoking floods.
  • The number and length of drought episodes will increase, particularly in summer.


The chosen region where to make the adaptations has a typical Continental-Mediterranean climate with long, dry and very hot summers, and equally long and severe winters. Springs and autumns are short and mild. The road conditions are highly sensitive to the evolution of the maximum and minimum temperatures as well as their daily oscillation. The main impacts considered due to climate change are those related to maximum temperatures in summer (expected increase of about 5ºC by the end of the century) and minimum temperatures in winter (expected decrease of around 3ºC). Ensuring safety and profitability entail adaptations or re-designed routes.


Transport infrastructures are designed to provide operation for over 100 years and more. Planning and designing new infrastructures, or re-designing and adapting existing ones, must rely solidly on sound projections of climate and on estimations of associated potential risks and impacts to ensure safe and profitable use. This assessment also includes other aspects such as environmental, socio-economic or technical, which will be provided by other platforms through an inter-operable data and models interchange environment. In that way, CLARITY is part of a compound modelling of future climate-driven impacts in the ground transport network.

The use of long-term climatic indicators and risk estimations will help companies to accurately estimate the required resources and budget for the adaptation tasks in the process of tendering for new concession bids. This will lead to higher competitiveness and efficiency and contribute to the infrastructure exploitation sustainability.


CLARITY will provide access to climate variables and indicators tailored for the assessment in the climatic short (seasonal) and mid (yearly) terms. Although, not extensively considered in the climatic domain, seasonal projections (two to four months) are frequently demanded by infrastructure operators. These services will help to activate seasonal campaigns and preventive works (due to frost, winds, heat waves, dramatic thermal oscillation, extreme temperatures, heavy precipitation etc.) including the scheduling of maintenance activities, selection of materials, equipment and methods in order to keep safety standards and ensure profitability and sustainability beforehand. This is particularly useful for companies holding concessions for roads maintenance and exploitation which will fine-tune and adapt strategic decisions in advance.


To summarise, CLARITY´s short-, mid- and long-term climate services have a broad collection of end-users. This demonstration case can help managers, whether they are public administration or licensed companies, to the efficient and cost-effective planning of resources and budget for the design and implementation of climate-driven impacts adaptation measures in the railway and highway networks worldwide. CLARITY climatic services provides data access and indicators to assess climate-proofing in all phases of the mentioned infrastructures’ lifecycle, namely:

  • Planning and design of new infrastructure, routing,

  • elaboration of construction regulations and recommendations,

  • selection of construction materials and methods,

  • infrastructure building phase planning,

  • long and mid-term maintenance scheduling, and infrastructure exploitation.

The CLARITY climate service is serving planners with decision-support as well as giving operational staff at stake-holder organizations a possibility to train and develop routines that permit a better preparedness for droughts, extreme precipitation, flooding, heat, air and water pollution events. Evaluating adaptations for urban planning projects, CLARITY develops its own strategy on how to help companies and cities. Through network and feedback we are able to achieve a great result together.