Paper Reviewed
Huerta, A. and Lavado-Casimiro, W. 2020. Trends and variability of precipitation extremes in the Peruvian Altiplano (1971-2013). International Journal of Climatology DOI: 10.1002/joc.6635.

Alarmists frequently claim widespread changes in climate are already underway in response to rising atmospheric CO2 concentrations over the past two centuries. With respect to precipitation, models have predicted both increases and decreases in this key parameter depending on location. They also forecast CO2-induced changes in precipitation variability and extremes.

To validate (or invalidate) such claims, robust data sets are needed from multiple locations across the globe to investigate precipitation trends on decadal to centennial time scales, or longer. The study of Huerta and Lavado-Casimiro (2020) performs such an analysis for the Peruvian Altiplano region of the Central Andes, South America.

Focusing on the drainage basin of Lake Titicaca (approximately 14°-17°S, 69°-71°W), the two researchers examined eleven extreme precipitation indices (EPIs) from 15 locations during the wet period (November-April) from 1971 to 2013. The eleven indices included (1) number of precipitation days, (2), maximum consecutive number of wet days, (3) mean consecutive number of wet days, (4) maximum consecutive number of dry days, (5) mean consecutive number of dry days, (6) number of very wet days, (7) total amount of precipitation on very wet days, (8) maximum 1-day precipitation, (9) maximum 5-day precipitation, (10) total amount of precipitation divided by the number of wet days, and (11) total precipitation.

Results of their analysis revealed, in the authors' words, that "there are no significant trends in EPIs towards wet or dry conditions in the Peruvian Altiplano during the study period 1971-2013." Such absence of trends is quite illuminating; it indicates supposed CO2-induced climate change has failed to alter the eleven key precipitation indices examined in this study despite an approximate 22% rise in atmospheric CO2. Thus, there is no evidence to conclude rising atmospheric CO2 is having any current impact on precipitation in the Peruvian Altiplano.