In Europa l’aria non è mai stata così secca. Lo rivela uno studio internazionale sugli anelli degli alberi condotto dall’Istituto federale di ricerca sulla foresta, la neve e il paesaggio (WSL).
Lo studio ha permesso di determinare la cosiddetta sete d’acqua dell’aria, cioè il deficit di pressione di vapore (VPD - Vapor Pressure Deficit) che descrive la differenza tra il contenuto d’acqua effettivo e quello massimo possibile dell’aria.
Il risultato? Negli ultimi decenni, la secchezza dell’aria è eccezionalmente elevata rispetto all’epoca preindustriale, in particolare nelle pianure dell’Europa centrale, nelle Alpi e nei Pirenei. L’aumento non sarebbe di tale portata, spiega il WSL, senza le emissioni di gas serra.
Il disco di una quercia di 200 anni proveniente da Büren an der Aare
Più è alto il deficit – afferma la ricercatrice Kerstin Treydte – “maggiore è il fabbisogno idrico delle colture”. Nelle foreste, aggiunge, “l’approvvigionamento di legno e il sequestro di carbonio sono compromessi, il che porta a incertezze sulla regolazione del clima e sul futuro stoccaggio di carbonio di questi ecosistemi”.
Spagna, siccità da record
Telegiornale 05.06.2023, 20:00
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