2007年-世界发展银行全球_The_Economic_Impact_of_Climate_Change_on_Kenyan_Crop_Agriculture___A_Ricardian_Approach_40页_1009kb

Summary of "The Economic Impact of Climate Change on Kenyan Crop Agriculture: A Ricardian Approach"

Core Content

This paper investigates the economic impact of climate change on crop agriculture in Kenya using a seasonal Ricardian model. It analyzes the relationship between climate variables (temperature and precipitation), hydrological conditions, soil characteristics, and agricultural productivity across 816 households in six Kenyan provinces. The study highlights the significant role of climate in shaping agricultural outcomes and emphasizes the need for adaptive strategies to mitigate the adverse effects of global warming.

Main Findings

• Climate Variables and Productivity:

  • Climate has a significant impact on agricultural productivity.
  • Temperature changes are more critical than precipitation changes for crop revenue.
  • Increased winter temperatures are associated with higher crop revenue, while increased summer temperatures have a negative impact.
  • Precipitation is positively correlated with net crop yield, but the relationship is non-linear.
  • A hill-shaped relationship exists between mean flow and net crop revenue.

• Soil and Land Use:

  • Andosols, irrigation, and household size are positively correlated with crop revenue.
  • Livestock ownership, farm size, and wage rates are inversely correlated with crop revenue.
  • Agricultural productivity and income are highest in high and medium potential zones and lowest in arid and semi-arid areas.

• Climate Change Scenarios:

  • Two global circulation models (CCC and GFDL) predict a 4°C increase in temperature and a 20% change in precipitation in Kenya by 2030.
  • High potential zones may see a 1% gain in net crop revenue (US$3.54 per hectare), while medium and low potential zones could face 21.5% loss (US$54 per hectare) under the CCC model.
  • Under the GFDL model, high potential zones would experience a loss of US$32 per hectare, and medium and low potential zones would face a loss of US$178 per hectare.
  • Temperature changes have a more significant impact on agricultural revenue than precipitation changes.

Adaptation and Farmer Perceptions

• Farmers in Kenya are aware of short-term climate change and have noted an increase in temperatures.
• Diversification (changing crop mix) is the most common adaptation measure, especially in high potential zones.
• Water conservation, irrigation, and shading/sheltering are primary adaptation strategies in drier regions.
• Constraints on adaptation include credit limitations, poverty, and lack of information, which prevent households from implementing effective water management strategies.

Policy Implications

• Adaptation is crucial to counter the effects of global warming on Kenyan agriculture.
• The government should play a key role in promoting climate change adaptation through:
  • Monitoring climate change and disseminating information via agricultural extension.
  • Improving water resource management, including water harvesting and wastewater recycling, especially in arid and semi-arid areas.
  • Enhancing credit provision and household welfare to support adaptation.
• Future research should focus on the impact of climate change on individual crops and livestock and the effectiveness of adaptation mechanisms used by farmers.

Methodology and Data

• Data Sources:

  • Household data from 816 households in six provinces (excluding Nairobi and North Eastern due to urbanization and aridity).
  • Climate data from the US Department of Defense (satellite data) and ARTES (Africa Rainfall and Temperature Evaluation System).
  • Hydrological data from the International Water Management Institute and University of Colorado.
  • Soil data from the Food and Agricultural Organization (FAO).

• Climate Data Overview:

  • Kenya has a bimodal rainfall pattern with long rains (March–May) and short rains (October–December).
  • Annual rainfall ranges from 250mm (arid areas) to 2000mm (high potential areas).
  • Annual temperature ranges from <10°C to 30°C, with higher temperatures in the Coast Province and lower temperatures in the Central Province.

• Sampling Strategy:

  • The study sampled 38 out of 46 districts across eight provinces.
  • Each district was divided into agroecological zones and farm types (large, medium, small).
  • At least four households were sampled from each agroecological zone, including one from each farm type.

Limitations and Future Research

• The study focuses on general crop agriculture and does not model individual crops or livestock.
• It does not assess the effectiveness of adaptation strategies used by farmers.
• Future research could use panel/time series data for more accurate estimates of climate change impacts.

Conclusion

The paper underscores the adverse effects of global warming on Kenyan agriculture, particularly in medium and low potential zones. It highlights the importance of temperature over precipitation in affecting productivity and recommends policy interventions focused on adaptation, information dissemination, and water resource management to safeguard agricultural output and ensure food security.