How does rising atmospheric CO2 affect marine organisms?

Click to locate material archived on our website by topic

A 47-Year History of Meteorological Drought in Paraguay

Paper Reviewed
Benitez, J.B. and Domecq, R.M. 2014. Analysis of meteorological drought episodes in Paraguay. Climatic Change 127: 15-25.

Introducing their study published in Climatic Change, Benitez and Domecq (2014) write that "droughts are the world's costliest natural disasters, causing an average US$ 6 - US$ 8 billion in global damages annually and collectively affecting more people than any other form of natural disaster," citing Wilhite (2000). And in light of these facts, it was only natural that the Paraguay researchers should conduct a study "to determine if the frequency and/or severity of droughts has increased or decreased in the last years, in response to climate change" within their own country. So using the Standardized Precipitation Index, they did just that for the period stretching from 1964 to 2011. And what did they find?

In the words of the two scientists, "no undeniable increasing trend in drought frequency/severity was detected" (see Figure 1 below), in spite of the fact that they report that according to projections of a CMIP5 multi-model ensemble, "during the 21st century drought frequency and severity is expected to increase in Southern South America as well as in Paraguay," as reported by Penalba and Rivera (2013). In fact, they found initial telling signs of just the opposite coming to pass, reporting that "during the first years of the records, from 1964 to 1978, the frequency of drought was high when compared with the period 1976-1999."

Once again, therefore, we have a case where theoretical models do not support real-world data.

Figure 1. Decadal counts of severe drought lasting either 12, 6, or 3 months in duration obtained from 20 meteorological stations in Paraguay. Severe drought events were classified as a Standard Precipitation Index (SPI) value ≤ -1.50 as described in the text. Adapted from Benitez and Domecq (2014).

Penalba, O.C. and Rivera,J.A. 2013. Future changes in drought characteristics over Southern South America projected by a CMIP5 multi-model ensemble. American Journal of Climate Change 2: 173-182.

Wilhite, D.A. 2000. Drought as a natural hazard: concepts and definitions. In: Wilhite, D.A. (Ed). Drought: A Global Assessment," Evanston, pp. 3-18.

Posted 2 March 2015