A climate warming of 1.5 degrees higher, the desirable limit established in agreement cop21 Paris last year, would be a transformation of Mediterranean ecosystems unprecedented since the beginning of human civilization, 10,000 years ago, according to research European climatologists.
Regional temperatures in the Mediterranean basin are currently 1.3 ° C higher than during the period 1880-1920, compared with an increase of 0.85 ° C worldwide in the same period, according to a study published in the journal Science.
This extra increase in temperature is relevant, since the ecosystems of the Mediterranean are an important area of global biodiversity (at least 1,500 endemic species) and provide many services such as clean water, flood protection and carbon deposits, so an additional temperature escalation would drastic effects.
The difference between 1.5 degrees and 2 degrees take us from an almost normal to the scale of the last 10,000 years, an extreme situation situation, the researchers believe, as important changes in less than a hundred years is a phenomenon not It is unprecedented.
Sediments and scenarios
The researchers used sediment cores pollen Mediterranean to reconstruct climate variability and ecosystem of the last 10,000 years. Then they used this information in different models to predict future changes in the temperature of the ecosystem.
Each sample pollen provides a picture of the vegetation of the past. With these data, and using different simulation models, the scientists could infer the climate for each type of vegetation.
Some of the scenarios conducted with these data drew the future of the Mediterranean region if nothing is done to stop global warming. A second set of simulations were done assuming that the goals set by governments in the Paris Conference cop21 are respected. This conference was marked as objective not exceed 2 ° C of temperature increase above pre-industrial levels, as ideal limit, 1.5 ° C.
In both scenarios, the ecological change is expected far exceeds what occurred during the Holocene, the interglacial period in which the temperature was milder and different icecaps disappeared or lost volume, which caused a rise in the level of sea over 10,000 years ago.
In the early stages of their simulations, if nothing is done to limit global warming, throughout southern Spain will become a desert, deciduous forests invade the mountains and thickets replace most of the deciduous forests of much of the Mediterranean basin.
Even worse: if the temperature is 5 to 6 degrees not reduce CO2 emissions, the desert would reach half of the Iberian Peninsula, according to the researchers.
This warming is manifested mainly by increasingly frequent droughts affecting agriculture and forests, whose impact is already being felt in the Mediterranean region. In addition, mild winters turn favor development of parasites affecting trees and contribute to their mortality.