Droughts in the Anthropocene

Peru – Diverse landscapes and monitoring challenges

Few countries in the world offer as much geographical diversity as Peru. Twenty-eight different climatic zones can be found throughout the country, including large desert areas, a coastline stretching along the Pacific Ocean, lush rainforests and the staggering mountain peaks of the Andes. Peru is considered one of the world’s megadiverse countries, harbouring a high number of endemic species and hosting 84 of the world’s 104 known ecological regions [1]. The coastline of Peru is the driest area in the country. Wind patterns over the South Pacific Ocean and the proximity to the mountains make this region a place where rainfall is sparse. The area is prone to water scarcity caused by seasonal meteorological drought, standing in stark contrast to the Amazon Basin of the country, which is highly prone to flooding. The movement of the Intertropical Convergence Zone (ITCZ) – an area where the northeast and southeast trade winds converge – causes a wet season followed by a dry season in Peru. During the summer months, the easterly trade winds transport humid air from the tropical Atlantic towards the Amazon Basin and the Andes, creating a wet season in most of the country. During the winter, these windsmove further north, creating a dry season with significantly less precipitation. However, in the summer months, the Andes function as a barrier for the winds coming from the Atlantic side, creating conditions where the eastern side of the Andes receives above 500mm/year of precipitation and the western side receives far less, with some areas as low as 150mm/ year on average [2]. These diverse precipitation regimes have made the creation of a national water plan for Peru highly challenging. Being able to accurately predict drought and events of water scarcity is of great importance to secure people’s livelihoods and the function of the economic sectors that depend on water. Of the

33 million inhabitants of Peru, about one-third reside along the desert coastal belt in the west part of the country. About one-fourth of the population are employed in the agricultural sector. Peru is also the second largest producer of copper in the world [3], and as such, a great portion of the population is employed in an industry highly dependent on the availability of fresh water. Accurate predictions are also important to make better informed policies and plans for the mitigation of and adaptation to the impacts of drought. The varied climate and topography of the country makes this a complex task, as there are huge challenges with using statistics and algorithms to produce climate models in areas with high variability in rainfall and climate. However, in recent decades, new algorithms have emerged, making predictions for these areas much more accurate. The National Meteorology and Hydrology Service of Peru (SENAMHI) has produced the Peruvian Interpolated data of SENAMHI’s Climatological and Hydrological Observations (PISCO), a gridded data set using information from 1981 to the present day, with a 0.1-degree spatial resolution [2]. The monitor is based on meteorological data taken from both observed and satellite information. The algorithm used to produce this data set combines geostatic and deterministic interpolation methods with a variety of rainfall sources, including visually measured, radar-gauged and infrared precipitation estimates. Different drought indexes and scales were tested based on the country’s situation. The data set operates on the national level and builds on six years of research in this area, using available information on the regionalization of droughts, characterization of duration, severity and intensity, hazard assessment and identification of dry periods [4]. The future of the project will focus on the relationship between hydrological

and meteorological droughts, the response of vegetation to droughts and the establishment of an early warning system in the next few years. UNESCO has also supported efforts at the national level to establish a drought observatory in Peru, where a consortium of partners developed the National Drought Observatory (ONS) [5]. The ONS has been fully integrated in the National Water Resources System (SNIRH), becoming a cornerstone of its drought management strategy. The system collects daily levels of rivers, reservoirs, streamflow, hydropower production, precipitation, temperature and vegetation conditions, as well as information on past droughts and near-future seasonal forecasts.

LATIN AMERICA AND THE CARIBBEAN

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