“Even if the objectives of the Paris Agreement are met, Mediterranean landscapes will change, and the dryer biomes will advance toward the north,” says Joel Guiot, a French researcher from the European Centre for Research and Teaching in Geosciences (CEREGE). At the latest climate change summit, in December 2015, 195 countries committed to keeping global temperature rises between 1.5ºC and 2ºC by the end of the century. “If not, the changes will be greater and a higher proportion of areas will be affected compared to any other period in the last 10,000 years,” he adds.
While the global thermal rise has been 0.85ºC, countries in the Mediterranean basin have gone up by 1.3ºC
Guiot, a paleoecologist, last year published a complete reconstruction of the Mediterranean area during the Holocene, the current geological age, which was born after the last great glaciation and has borne witness to the rise of humans. To do so, he utilized tens of thousands of pollen samples trapped in sediments. “Pollen offers a unique archive of the historic dynamic of vegetation,” he explains.
Together with his colleague Wolfgang Cramer, Guiot has modeled how the different Mediterranean landscapes will look by the end of the century. The results, published in the journal Science, have once again confirmed a trend that had been seen in previous studies: the Mediterranean zone will warm up more than the global average. Since the industrial revolution, while the global thermal rise has been 0.85ºC, countries in the Mediterranean basin have gone up by 1.3ºC. Another of their conclusions confirms that the unusually high averages seen this century so far had never been registered during the Holocene.
As for the future of Mediterranean forests, the study shows that even if the Paris goals are met, trees and other vegetation would be confined to higher-altitude areas and the north. Only a temperature fall of 1.5ºC would see the Mediterranean stay as it is now.
University lecturer José Manuel Moreno Rodríguez
The worst-case scenario predicted by climatologists over the coming century is a concentration of CO2 that is three times higher than the current level of 400 parts per million, and a rise in average temperatures of over 4ºC. In that case, the southern third of Spain would be dominated by an arid landscape.
“If the Paris goals are met, we would see a temperature rise of close to 3ºC, which would mean significant changes in our environment,” explains Castilla-La Mancha University lecturer José Manuel Moreno Rodríguez. For this ecologist, who is one of the Spanish researchers from the UN’s Intergovernmental Panel of Climate Change Experts, “an increase of 4ºC would be a huge change, like bringing Casablanca to Madrid.”
English version by Simon Hunter.