The Ministry of Ecological Transition, Fight against Climate Change and Territorial Planning of the Government of the Canary Islands has obtained climate projections for the remaining years of the 21st century. Through the work of the Earth and Atmosphere Observation Group (Gota), forecasts show an increase of up to 4.5 degrees in maximum daytime temperatures; a greater number of tropical nights; fewer episodes of extreme heat, but of longer duration; and a decrease of up to 30% in rainfall in a large part of the archipelago.
The regional minister responsible for the area, José Antonio Valbuena, points out that these figures are the result of a three-year agreement signed with the University of La Laguna (ULL), whose budget amounted to 300,000 euros from the regional accounts. This publication is presented in open format, with a grid resolution of 3×3 kilometres, with the WRF (Weather and Research Forecasting) mesoscale model for the climate change scenarios of the Intergovernmental Panel on Climate Change (IPCC). “It is essential that public administrations know the climate scenarios we will face in the coming years, in order to properly plan adaptation and mitigation actions in the Canary Islands”, explains Valbuena. “Always based on the knowledge and work of the Canarian universities,” he said.
Among other conclusions, the projections drawn from this initiative determine that daily minimum temperatures could rise, on average, between one and three degrees by the end of the century in the most unfavourable scenario. In such circumstances, an increase in the number of tropical nights – when the minimum temperature does not fall below 20 degrees – is not ruled out. In the worst-case scenario, the increase will average 45 days for the whole region: the highest values would be in the eastern islands and coastal areas.
Another relevant indicator is daily maximum temperatures, which could rise by as much as 4.5 degrees Celsius in highland areas of the islands by the end of the century in the worst-case scenario. Another parameter that would be modified by this value would be that of warm episodes. These projections show that the number of extreme heat events decreases, but the duration of these events will be longer.
With regard to rainfall, there is a greater dispersion in the data, although everything points to an overall decrease in annual rainfall, with the highest areas of the islands being the most affected. It is estimated that the decrease could be around 30% by the end of the century in a large part of the territory. The various simulations coincide in the fall in the number of days with precipitation, both light and heavy rainfall, which will contribute to an increase in the risk of drought. All these variations in temperature and precipitation will have an effect on other aspects such as soil moisture, relative air humidity, evapotranspiration, aridity of the terrain and the forest fire season.
WRF is a state-of-the-art mesoscale numerical weather forecasting formula designed for operational forecasting and for use in atmospheric research. It is applicable on scales ranging from metres to thousands of kilometres and allows researchers to make “real or idealised simulations”. It has “operational prediction capabilities, a flexible and robust platform and incorporates advances in physics, numerical-mathematical and data assimilation, contributions from many scientific developers”.
The climate projections obtained as a result of this collaboration agreement are now available on the digital portal.
The State Meteorological Agency (Aemet) describes that many climate change impact, vulnerability and future risk assessment analyses are based on impact archetypes that require quantitative climate data scenarios at an appropriate spatial and temporal resolution: “Obtaining territorialised climate change projections is subject to a number of sources of uncertainty that affect all steps of the process”.