Food Insecurity
This lab will use data from the Famine Early Warning System (FEWS), a system used for predicting and monitoring food insecurity. We will be looking at FEWS data layers in Google Earth to examine the threat of famine in southern Somalia in late 2010 and early 2011. A majority of Somalia's population is rural and engaged in nomadic pastoralism, a type of agriculture that focuses on the raising of livestock. Pastoralism is dependent on seasonal rains that provide grass feed for livestock.
Located close to the equator, Somalia has seasons that would be unfamiliar to most of us. Temperatures are hot year-round, and seasons are defined based on rainfall:
- Jilaal is a dry season that normally lasts from December to March
- Gu is the main rainy season that normally occurs from April to June
- Hagaa is a dry season that normally lasts from July to September
- Dyer is a secondary rainy season that normally occurs from October to December
If the dyer rains fail to come, then dry conditions can persist from one gu to the next gu. Low rainfall during the dyer season will prevent the growth of rangeland grasses that livestock depend on. Starvation of livestock can result in famine for pastoralists who depend primarily on livestock products for their daily caloric intake.
A severe famine occurred in Somalia in 1991 and 1992, affecting more than 1 million people and killing an estimated 200,000 people. The famine was greatly exacerbated by a civil war during that time. Continuing political instability has made providing aid to Somalia in subsequent famines very difficult.
FEWS combines satellite data with expert analysis to monitor climatic and political factors that contribute to food insecurity. We will be looking at three types of FEWS data layers:
- Rainfall Estimate approximates the amount of rainfall received in a location. Rainfall Estimate can be expressed as either the amount of rainfall or as an anomaly from average rainfall. Negative anomalies indicate lower than average rainfall. Positive anomalies indicate higher than average rainfall.
- Land Surface Temperature can be expressed as temperature or as an anomaly from average temperature. Positive anomalies indicate hotter than average temperatures. Land Surface Temperature can be used to estimate evapotranspiration.
- Water Requirement Satisfaction Index is a comparison of the water needs of a particular crop to the amount of water supplied by rainfall. In this lab, we will be looking at the WRSI for rangeland grasses. High WRSI values will indicate that grasses should be growing vigorously. If minimal precipitation is received during a wet season, then WRSI values will be very low, indicating that growth of rangeland grass may not have started.
Begin by opening "Rainfall Estimate.kmz". This file contains 12 monthly rainfall estimate layers for 2010. Use the time slider to examine each of the monthly rainfall layers.
1. How does the spatial pattern of rainfall shift over Africa during the course of a year? Why does this change occur?
The difference between the Rainfall Estimate layers and average rainfall will give us the rainfall anomaly. Uncheck the Rainfall Estimate folder so this layer is no longer visible, and load "Rainfall Anomaly.kmz". Use the time slider to examine the monthly rainfall anomalies during 2010.
For the remainder of the lab, focus your analysis on southern Somalia to the south and west of Muqdisho (Mogadishu).
2. During which months of 2010 did southern Somalia have higher than average precipitation? During which months of 2010 did southern Somalia have lower than average precipitation?
3. Examining both the Rainfall Estimate and Rainfall Anomaly layers, describe the dyer rainy season in 2010.
Make the Rainfall Estimate and Rainfall Anomaly layers invisible, and load "LST Anomaly.kmz".
4. During which months of 2010 did southern Somalia have lower than average temperature? During which months of 2010 did southern Somalia have higher than average temperature?
5. Based on rainfall and temperature anomalies, are rangeland grasses likely to be growing during the 2010 dyer season? Explain.
Turn off the Land Surface Temperature Anomaly layers invisible, and then load "WRSI.kmz". This file contains the rangeland Water Requirement Satisfaction Index values at the end of the dyer season. The layer "1995-1996" shows the WRSI from January 1996, following the 1995 dyer season. Use the time slider to examine post-dyer WRSI in each year, and answer the following questions.
6. Describe the WRSI in southern Somalia for the 2010-2011 layer. Based on this layer, was there a danger of famine in Somalia in early 2011?
7. Based on the WRSI layers, in which years was famine most likely to have occurred in southern Somalia? In which years was famine least likely to have occurred?