CHG - Data - Climate Trend Analysis
DATA
Climate Trend Analysis
FEWS NET-related Climate Change and Food Security Trend Analyses

The Climate Hazard Group1, in collaboration with the director of the US Agency for International Development's Famine Early Warning Network2 (FEWS NET) and colleagues from the US Geological Survey3, has developed and are developing a unique series of trend analyses focused on supporting African climate adaptation, agricultural development and improved drought early warning. The goal of this program is to provide humanitarian and governmental decision makers with spatially detailed information about recent climate trends, assessments regarding the potential persistence of these trends, and evaluations of their potential impacts on food and water security. The work combines 'top down' large scale climate attribution analysis and diagnostics with local scale 'bottom up' climate trend mapping (based primarily on interpolated station data). The goal of this approach is to identify where and why climate has been changing recently (i.e. over the past twenty years). This information can be used to guide development towards climatically secure regions, identify emerging areas of water and food insecurity, and help identify, in advance, when and where combinations of large scale climate conditions and local fragility may combine to produce food crises4.

Local trend analyses

The FEWS NET monitoring system was put in place after the tragic Ethiopian famine in 1983/85. FEWS NET's extensive information about livelihoods and insecure populations helps focus CHG analysis at the local scale. This framework, combined with high resolution time series of interpolated trends, climatological means and monthly time series of precipitation and temperature, supports brief analyses of recent climate trends and their potential impacts on agriculture and food security. These reports are published as USGS Fact Sheets. The mapping procedure supporting climate analysis is detailed in a recent book chapter5. At present 8 reports are available.

A Climate Trend Analysis of Mali (USGS Fact Sheet 2012-3105)

Conclusions:

  • Summer rains have remained relatively steady for the past 20 years, but are 12 percent below the 1920-1969 average.
  • Temperatures have increased by 0.8° Celsius since 1975, amplifying the effect of droughts.
  • Cereal yields are low but have been improving.
  • Current population and agricultural trends indicate that increased yields have offset population expansion, keeping per capita cereal production steady.
A Climate Trend Analysis of Burkina Faso (USGS Fact Sheet 2012-3084)

Conclusions:

  • Summer rains have remained steady over the past 20 years, but remain 15 percent below the 1920–69 average.
  • Temperatures have increased by 0.6° Celsius since 1975, amplifying the effect of droughts.
  • The amount of farmland per person is low, and declining.
  • Burkina Faso has offset rapid population growth with improved yields.
  • Continued yield growth would maintain current levels of per capita food production.
A Climate Trend Analysis of Chad (USGS Fact Sheet 2012-3070)

Conclusions:

  • Summer rains have decreased in eastern Chad during the past 25 years.
  • Temperatures have increased by 0.8° Celsius since 1975, amplifying the effect of droughts.
  • Crop yields are very low and stagnant.
  • The amount of farmland per person is low, and declining rapidly.
  • Population growth combined with stagnating yields could lead to a 30 percent reduction in per capita cereal production by 2025.
  • In many cases, areas with changing climate are coincident with zones of substantial conflict, indicating some degree of association; however, the contribution of climate change to these conflicts is not currently understood.
A Climate Trend Analysis of Niger (USGS Fact Sheet 2012-3080)

Conclusions:

  • Summer rains have increased during the past 20 years and have almost returned to 1960–89 levels.
  • Temperatures have increased by 0.6° Celsius since 1975, amplifying the effect of droughts.
  • Crop yields are very low and stagnant, and the population is growing very rapidly.
  • Niger has offset very rapid population growth with a large expansion of cultivated land.
  • If the expansion of farmland slows down, stagnant yields and population growth could lead to increased food insecurity.
A Climate Trend Analysis of Uganda (USGS Fact Sheet 2012-3062)

Conclusions:

  • Both spring and summer rains have decreased in Uganda during the past 25 years.
  • The magnitude of observed warming, especially since the early 1980s, is large and unprecedented within the past 110 years, representing a large (2+ standard deviations) change from the climatic norm.
  • Cropping regions in the west and northwest appear most affected by the observed changes in climate.
  • Rainfall declines in the west and northwest threaten Uganda's future food production prospects.
  • Warming temperatures may be adversely affecting coffee production.
  • Rapid population growth and the expansion of farming and pastoralism under a drier and warmer climate regime could dramatically increase the number of at risk people in Uganda during the next 20 years.
  • In many cases, areas with changing climate are coincident with zones of substantial conflict, indicating some degree of association; however, the contribution of climate change to these conflicts is not currently understood.
A Climate Trend Analysis of Ethiopia (USGS Fact Sheet 2012-3053)

Conclusions:

  • Spring and summer rains in parts of Ethiopia have declined by 15-20 percent since the mid-1970s.
  • Substantial warming across the entire country has exacerbated the dryness.
  • An important pattern of observed existing rainfall declines coincides with heavily populated areas of the Rift Valley in south-central Ethiopia, and is likely already adversely affecting crop yields and pasture conditions.
  • Rapid population growth and the expansion of farming and pastoralism under a drier, warmer climate regime could dramatically increase the number of at-risk people in Ethiopia during the next 20 years.
  • Many areas of Ethiopia will maintain moist climate conditions, and agricultural development in these areas could help offset rainfall declines and reduced production in other areas.
A Climate Trend Analysis of Sudan (USGS Fact Sheet 2011-3072)

Conclusions:

  • Summer rains in western and southern Sudan have declined by 10–20 percent since the mid-1970s.
  • Observed warming of more than 1 degree Celsius is equivalent to another 10–20 percent reduction in rainfall for crops.
  • The warming and drying have impacted southern Darfur and areas around Juba.
  • Rainfall declines west of Juba threaten southern Sudan's future food production prospects.
  • In many cases, areas with changing climate are coincident with zones of substantial conflict, suggesting some degree of association; however, the contribution of climate change to these conflicts is not currently understood.
  • Rapid population growth and the expansion of farming and pastoralism under a more variable climate regime could dramatically increase the number of at-risk people in Sudan over the next 20 years.
A Climate Trend Analysis of Kenya (USGS Fact Sheet 2010/3074)

Conclusions:

  • Long rains in central Kenya have declined more than 100 millimeters since the mid-1970s. This decline is probably linked to warming in the Indian Ocean, and seems likely to continue.
  • The observed drying tendency is the opposite predicted by the 4th Intergovernmental Panel on Climate Change (IPCC) assessment.
  • A warming of more than 1° Celsius may exacerbate drying impacts, especially in lowland areas.
  • The drying trends could particularly impact densely populated areas to the east, north, and north-west of Nairobi.
  • Critical surplus crop growing areas in Central Kenya are threatened, and the amount of prime arable land could diminish substantially.
Supporting Publications

FEWS NET trend analyses are supported by peer reviewed research targeted at understanding the large scale climate linkages, improving our understanding of linkages between drought and health, agriculture and demography, or developing better techniques for interpolating environmental variables. We list in reverse chronological order a few relevant publications in each category.

[+] Large scale climate: [-] Large scale climate:
[+] Linkages: [-] Linkages:
  • Grace, K., Davenport, F., Funk, C. and McNally, A (2012) Child Malnutrition and Climate in Sub-Saharan Africa: An analysis of recent trends in Kenya, Applied Geography, in press.
  • Jankowska, MM; D. Lopez-Carr; C. Funk; GJ Husak; ZA Chafe (2011) Climate Change and Human Health: Spatial Modeling of Water Availability, Malnutrition, and Livelihoods in Mali, Africa, J. of Applied Geography, 33 (2012) 4-15. http://dx.doi.org/10.1016/j.apgeog.2011.08.009
  • Harrison L., J. Michaelsen, C. Funk, G. Husak (2011) Effects of temperature changes on maize production in Mozambique, Climate Research, V46: 211-222, doi: 10.3354/cr0097946.211-222. http://www.int-res.com/articles/cr_oa/c046p211.pdf
  • Funk C. and Brown, M. (2009) Declining Global Per Capita Agricultural Production and Warming Oceans Threaten Food Security. (2009) Food Security. DOI 10.1007/s12571-009-0026-y. http://www.springerlink.com/content/fw645377u3587404/fulltext.pdf
[+] Interpolation: [-] Interpolation:
  • Funk C, J. Michaelsen and M. Marshall (2012) Mapping recent decadal climate variations in precipitation and temperature across Eastern Africa and the Sahel, Chapter 14 in "Remote Sensing of Drought: Innovative Monitoring Approaches", edited by B. Wardlow, M. Anderson and J. Verdin, in press. ftp://chg.geog.ucsb.edu/pub/pubs/mapping_decadal_variations.pdf
  • Funk C, Verdin J.P. (2010) Real-Time Decision Support Systems: The Famine Early Warning System Network. in Gebremichael M, Hossain F, eds., 2010, Satellite Rainfall Applications for Surface Hydrology:. Springer, Netherlands, pp. 295-320. ftp://chg.geog.ucsb.edu/pub/pubs/RealtimeDSS_for_FEWS_NET_final.pdf
  • Funk, C., Husak, G., Michaelsen, J., Love, T. and Pedreros, D. (2007) Third generation rainfall climatologies: satellite rainfall and topography provide a basis for smart interpolation, Crop and Rangeland Monitoring Workshop, Nairobi, March 2007, Extended Abstract. ftp://chg.geog.ucsb.edu/pub/pubs/CRAM_2007_thirdgen_rainfall.pdf
  • Husak, G., Michaelsen, J., Funk, C., (2007) Use of the Gamma Distribution to Represent Monthly Rainfall in Africa for Drought Monitoring Applications, Int. J. of Clim. 27(7): 935-944.
  • Funk, C. and J. Michaelsen, 2004: A simplified diagnostic model of orographic rainfall for enhancing satellite-based rainfall estimates in data poor regions, J. of Appl. Met., (43): 1366-1378. ftp://chg.geog.ucsb.edu/pub/pubs/VDELB.pdf
  • Funk, C., J. Michaelsen, J. Verdin, G. Artan, G. Husak, G. Senay, H. Gadain, and T. Magadzire, 2003: The Collaborative Historical African Rainfall Model: Description and Evaluation. Int. J. of Clim., (23)47-66. ftp://chg.geog.ucsb.edu/pub/pubs/CHARM_IJOC_article.pdf