How warmer and drier will the Mediterranean region be at the end of the twenty-first century?

  • PDF / 3,697,210 Bytes
  • 12 Pages / 595.276 x 790.866 pts Page_size
  • 66 Downloads / 197 Views

DOWNLOAD

REPORT


ORIGINAL ARTICLE

How warmer and drier will the Mediterranean region be at the end of the twenty-first century? Philippe Drobinski 1 & Nicolas Da Silva 1 & Sophie Bastin 2 & Sylvain Mailler 1 & Caroline Muller 1 & Bodo Ahrens 3 & Ole B. Christensen 4 & Piero Lionello 5 Received: 1 October 2018 / Accepted: 14 May 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020

Abstract Nearly all regions in the world are projected to become dryer in a warming climate. Here, we investigate the Mediterranean region, often referred to as a climate change “hot spot”. From regional climate simulations, it is shown that although enhanced warming and drying over land is projected, the spatial pattern displays high variability. Indeed, drying is largely caused by enhanced warming over land. However, in Northern Europe, soil moisture alleviates warming induced drying by up to 50% due to humidity uptake from land. In already arid regions, the Mediterranean Sea is generally the only humidity source, and drying is only due to land warming. However, over Sahara and the Iberian Peninsula, enhanced warming over land is insufficient to explain the extreme drying. These regions are also isolated from humidity advection by heat lows, which are cyclonic circulation anomalies associated with surface heating over land. The cyclonic circulation scales with the temperature gradient between land and ocean which increases with climate change, reinforcing the cyclonic circulation over Sahara and the Iberian Peninsula, both diverting the zonal advection of humidity to the south of the Iberian Peninsula. The dynamics are therefore key in the warming and drying of the Mediterranean region, with extreme aridification over the Sahara and Iberian Peninsula. In these regions, the risk for human health due to the thermal load which accounts for air temperature and humidity is therefore projected to increase significantly with climate change at a level of extreme danger. Keywords Water cycle . Warming . Dryness . Clausius-Clapeyron law . Heat lows . Regional climate change . Human health . Europe . Mediterranean . HyMeX . MED-CORDEX

Introduction The Mediterranean region, i.e., the region of lands around the Mediterranean Sea that have a Mediterranean climate Topical Collection on Climate change impacts in the Mediterranean * Philippe Drobinski [email protected] 1

LMD/IPSL, Ecole Polytechnique, Institut Polytechnique de Paris, ENS, PSL Research University, Sorbonne Université, CNRS, Palaiseau, France

2

LATMOS/IPSL, UVSQ, Université Paris-Saclay, Sorbonne Université, CNRS, Guyancourt, France

3

Institute for Atmospheric and Environmental Sciences, Goethe-University Frankfurt, Frankfurt, Germany

4

Danish Meteorological Institute, Copenhagen, Denmark

5

CMCC, Lecce, Italy

(Köppen 1936), has been identified as one of the most sensitive and vulnerable regions in the world to climate change (e.g. Giorgi 2006), with a projected increase in interannual rainfall variability in addition to a strong warming and drying for 2080–99