#insights

Climate change directly affects the weather, and extreme events such as floods and droughts. Given the certainty that it is occurring and that it will have multiple serious consequences, we are now finally considering what actions have to be taken to offset its effects.

Climate change today is different in two ways compared to how it was before; on the one hand, one of the causes is the emission of greenhouse gases derived from human activity and, on the other, the high speed at which the change is taking place, which is forcing nature and human societies to adapt quickly.

The focus right now is on the magnitude of climate change and on the actions that have to be implemented to address its consequences.

Predicting the future weather

To adapt to climate change, we must first estimate what the future climate will be like. To this end, Global Climate Models (GCMs) and Regional Climate Models (RCMs) have been developed. The first ones are the main tool available to simulate the processes that make up the climate at a global level, while the second ones analyze the climate in a region in sufficient detail for impact assessment.

One of the variables handled by GCMs is the concentrations of greenhouse gases that could be reached in the future. Since these are not known, several scenarios are proposed depending on the success in controlling them; these are called representative concentration trajectories (RCP). Although there are several, the most common are:

• RCP 4.5: a scenario in which greenhouse gas emissions increase, but moderately during the first half of the century before stabilizing. This is an intermediate situation that keeps emissions under control. The amount of global warming would be around 1.7 ºC to 3.2 ºC.

• RCP 8.5: a much less favorable scenario in which no additional efforts are made to reduce greenhouse gases. Global warming would reach 3.4 ºC to 5.4 ºC.

Once the climate projections for the RCPs that we want to analyze are obtained, the impacts can be estimated and the measures that can be taken are proposed.

In this field, Sener has conducted, based on specific climate forecasts, an Analysis of the Effect of Climate Change on Flooding in the Autonomous Community of the Basque Country, which can be used to predict the possible impacts that the flooding that is estimated to occur will have on the coast and in the rivers. Sener thus makes it possible for prevention, protection, preparedness and recovery measures to be proposed, in coordination with the Flood Risk Management Plans. We were also able to analyze the uncertainties involved in order to adequately define both the projections and the proposed measures, thus facilitating the decision-making.