Shea and Climate
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This document discusses the relationship between shea trees, climate, and climate change in West Africa. It summarizes research showing that the distribution of shea trees is correlated with temperature and rainfall. Climate models predict the suitable habitat for shea will expand northward under climate change scenarios. The document also notes that vegetation influences regional rainfall patterns and that shea parklands store a large amount of carbon.
Shea and Climate
- 1. Shea and Climate Jon Lovett University of Leeds
- 4. 30-07-2008 Early season hurricane formation off Dakar from EUMETSAT http://www.eumetsat.int/Home/index.htm
- 5. 08-08-2008 Hurricane Alley in full flow from EUMETSAT http://www.eumetsat.int/Home/index.htm
- 6. 04-09-2008 Hurricane Ike reaches category 4 coming out of Hurricane Alley from EUMETSAT http://www.eumetsat.int/Home/index.htm Ike
- 7. 09-09-2008 Hurricane Ike over Cuba from EUMETSAT http://www.eumetsat.int/Home/index.htm
- 8. 17-09-2008 Hurricane Ike reaches Europe from EUMETSAT http://www.eumetsat.int/Home/index.htm
- 9. 23-09-2008 Heavy rain in Spain: 250 l/m2 in two hours in Sueca in eastern Spain. Meteosat-9 HRV Europe RGB - 17:00 UTC.
- 12. IPCC ‘Climate Change 2007’ • Frequency of heavy precipitation events has increased over most land areas - consistent with warming and increases of atmospheric water vapour • Drying in the Sahel, the Mediterranean, southern Africa and parts of southern Asia • More intense and longer droughts observed since the 1970s, particularly in the tropics and subtropics
- 13. high low Modelled present day African plant species richness Assuming species occur at all climatically suitable places Sommer et al. Nees Institute for Biodiversity of Plants, Bonn Effect of Climate Change Africa
- 14. Patterns of African plant species richness in 2100 Assuming species move into new habitats and occur at all climatically suitable places Sommer et al. Nees Institute for Biodiversity of Plants, Bonn Effect of Climate Change Africa
- 15. Shea presence localities Distribution data from John Hall (University of Wales, Bangor); plot locations from Burkina Faso, Mali and Ghana; one record from TROPICOS – 241 points in total (216 paradoxa, 25 nilotica) – 216 locations to nearest minute, remainder to nearest degree INNOVKAR WP2: Shea distribution under climate change Platts, Poudyal, McClean (February 2011)
- 16. Analysing present day distribution • Using generalised additive models (GAMs), the present day shea distribution was correlated with climate, topography, agro-ecological zone data and fire radiative power • Predictor variables were chosen using two contrasting stepwise selection procedures: beginning with a null/full model, variables were added/removed according to Akaike/Bayesian Information Criterion, respectively • Platts, Poudyal, McClean INNOVKAR WP2 INNOVKAR WP2: Shea distribution under climate change Platts, Poudyal, McClean (February 2011)
- 17. INNOVKAR WP2: Shea distribution under climate change Platts, Poudyal, McClean (February 2011) Shea distribution (present) predicted by a GAM using climate, topography, soil constraints and fire intensity Shea distribution (present) predicted by a GAM using climate variables only (mean temperature, moisture index and driest month rainfall)
- 18. Climate scenarios INNOVKAR WP2: Shea distribution under climate change Platts, Poudyal, McClean (February 2011) Summary of temperature changes forecast according to various IPCC SRES emissions scenarios (IPCC, 2007). A1: maximum energy requirements, with emissions differentiated according to fuel sources (A1Fl, fossil intensive; A1T, technological development of non-fossil sources; A1B, balance across sources). B1: minimum energy requirements and low emissions. A2: high energy requirements; emissions less than A1Fl. B2: low energy requirements, but emission greater than B1. Considered here are SRES scenarios A2 and B2.
- 19. INNOVKAR WP2: Shea distribution under climate change Platts, Poudyal, McClean (February 2011) Maps showing modelled climatic suitability for shea under current and future climate scenarios (extrapolating the GAM predictions)
- 20. INNOVKAR WP2: Shea distribution under climate change Platts, Poudyal, McClean (February 2011) Plots showing forecast changes in the number of 10 arc-minute grid cells providing climatically suitable conditions for shea. Viable conditions are defined by model predictions of at least 0.5 The two SRES scenarios (A2 and B2) returned similar results for the first half of the 21st century, but thereafter the A2 scenario (higher emissions) resulted in a more rapid increase in the amount of climate-space suitable for shea, particularly within its current latitudinal range (0°-15°N).
- 21. Satellite data and high resolution modelling studies show that storms need heterogeneous soil to initiate In particular, afternoon convection over dry Sahel regions needs this variation in ground surface to initiate. Convection forms over gradients in soil moisture.
- 22. Air passage over forested regions enhances seasonal rainfall by up to 10 mm per day
- 23. Carbon Estimates • Shea parkland 20-50 MgC/ ha • 3.7 million km2 Sahel-Savannah wooded parkland zone • = 74,000,000,000 tonnes C (@20 MgC/ ha) • = 271,000,000,000 tonnes CO2 • World CO2 emissions: 33,376,327,000 tonnes CO2 • Shea parkland C stock equivalent to more than 8 times global CO2 emissions
- 24. Conclusion • Sahelian climate unpredictable • Climate change models predict a drier Sahel • Bioclimatic envelope modelling shows major shifts in vegetation; with Shea range expanding • Vegetation affects Sahel rainfall; and carbon storage/ sequestration can mitigate climate change