households made any effort to counter long-term temperature changes (40% reported no adaptations), compared to 78% in the case of precipitation. For long-term temperature changes, two main adaptations emerge: crop diversification and shading/sheltering or planting of trees. As in the case of short-term climate change, crop diversification is more common in high potential zones, while shading/sheltering is more common in medium and low potential zones. In the case of crop diversification, farmers in Kenya are known to switch to more adaptive crop varieties such as fast growing and hybrid varieties. This supports the literature which shows that long-term adaptation measures mainly take the form of changing crop types, such as drought tolerant varieties. However, the low percentages adopting this measure could be due to lack of knowledge, skills and finances (Kurukulasuriya & Rosenthal 2003). Shading/sheltering/tree planting is important because in addition to countering climate change it is also a form of soil conservation.

Improved water management is one of the most important long-term adaptation options that countries must pursue. Though few households reported water management measures for long-term changes in temperature, this contrasts with adjustments for long-term precipitation changes, which included increased water conservation, crop diversification and increased use of irrigation. The low overall adoption rates could be attributed to scarcity of resources, including water for irrigation, and lack of knowledge about the importance of these options. Indeed, only about 10% of the overall sample of 816 households reported having used any irrigation at all.

The above analysis shows that farming households in Kenya are aware of both short- and long-term climate change. Further, more than 80% of households have implemented various adaptation mechanisms to counter short-term climate variations, compared to 60% and 78% that have implemented various mechanisms to counter long-term temperature and precipitation changes respectively. Though we did not investigate the role of government in promoting farm level adaptations to climate change, it can play a critical role in encouraging adaptations. For instance, improving knowledge through agricultural extension could encourage both short- and long-term adaptations to climate change. Kurukulasuriya and Rosenthal (2003) argue that there is a clear and distinct role for strengthening extension services in agriculture in vulnerable countries to enhance farmer awareness of potential adaptation response options. Policies that improve household welfare are, however, a priority for both short- and long-term adaptation measures, given that 60% of all households reported that adaptation is constrained by lack of credit and income.

# **7. Conclusions and implications for policy**

This paper explores the impact of climate on crop revenue in Kenya, using primary household level data enriched with secondary climate, hydrological and soil data. We concentrated on a seasonal Ricardian model to assess the impact of climate on net crop revenue per acre. We first assessed the impact of climate on agriculture by estimating models with climate factors only, then tested the impact of hydrological, soil and household variables.

Our results suggest that climate affects agricultural productivity. Increased winter temperatures increase net crop revenue, while high summer temperatures decrease it. Increased precipitation increases net crop revenue. The results further show that there is a non-linear relationship between temperature and crop revenue on the one hand and between 23