Megadroughts in Portugal?


Portugal could be subject to “megadroughts” lasting for many years by the end of the century, according to climate models drawn up by researchers at Newcastle University.

The study, entitled ‘Assessing the threat of future megadrought in Iberia’, stated that under the worst projections, the area could see a 15-year period of rainfall at less than half the average level.

Researchers selected a total of 15 different climate models used by leading scientific bodies around the world, including Nasa, the UK Met Office and the Max Planck Institute for Meteorology.

According to the Independent, they found that, while the models produced a range of different results, “extreme future droughts” were predicted by ones which could accurately simulate what had happened in the past.

The researchers examined the three main river basins of the Iberian Peninsula, the Tagus, Douro and Guadiana.

Writing in the International Journal of Climatology, they said: “All models project an intensification of drought conditions for the Douro, Tagus and Guadiana.
“However they strongly disagree on the magnitude of these changes.

“Some project small increases in drought conditions but most project multi-year droughts reaching up to … eight years of mean annual rainfall missing (over a 15-year period) … by the end of the century.

“Despite the fact that the two models projecting the most severe future drought conditions overestimated historical drought, extreme future droughts were also projected by models that simulated historical droughts with similar conditions to the observations.”

According to a 424-page study published earlier this year by the European Environment Agency (EEA) entitled ‘Climate change, impacts and vulnerability in Europe 2016’, cash-strapped Portugal has suffered monetary losses of 6.8 billion euros as a result of climate change between 1980 and 2013.

The EEA study does not paint a bright picture for Portugal, and while it focuses on damage and cost of past weather events, the forecast remains bleak.

Southern and south-eastern Europe is projected to be a climate change hotspot, as it is expected to face the highest number of adverse impacts, the EEA report reveals.

“This region is already experiencing large increases in heat extremes and decreases in precipitation and river flows, which have heightened the risk of more severe droughts, lower crop yields, biodiversity loss and forest fires”, researchers found, warning further that more frequent heatwaves and changes in the distribution of climate-sensitive infectious diseases are expected to increase risks to human health and well-being.

In terms of the effects of climate change, in 2016, Portugal broke weather records in June, July, August and September, with temperatures reaching record highs, while rainfall was exceptionally low. Figures showed that July 2016 was the second hottest on record, and was only beaten by temperatures reached in 1989.

Average maximum temperatures were also the highest ever in July, with highs of 32.19 degrees, almost four degrees above what would normally be expected for the month of July.
June 2016 was also the hottest since records were first logged.

Overall, one in four weather stations on mainland Portugal recorded a temperature of 40 degrees on at least one occasion between the final fortnight of June and the beginning of July. Portugal has in recent years smashed a host of weather records. December 2015 had been the second warmest December in Portugal since records began in 1931, while the whole of 2015 was the second warmest in the past 15 years, and the fourth driest.

Average temperatures in Portugal have in the last 40 years increased at a rate of 0.5 degrees per decade – twice as fast as globally.