variation between years can hide some of the actual weather impacts, extreme conditions in one of the few survey years can bias some of the results. To mediate some of these shortcomings, panel data sets that cover larger time horizons are needed.

# **5. Conclusions**

The results in this paper show that weather variation and income changes over time in rural Vietnam are related. They also warn against an oversimplification of this relationship as there is a breadth of weather impacts, which are highly dependent on socioeconomic groups, climate zones, and income activities, and even the severity of weather conditions. In addition, income effects do not only depend on the intensity of the rainfall or temperature shock, but also on the timing of the shock and the location‐specific optimal rainfall and temperature levels.

Despite this complexity the data allow identifying some general patterns. Warmer temperatures and heat extremes have income‐reducing effects in all climate contexts and for all socioeconomic groups, including poorer households and ethnic minorities. While most income activities are negatively affected by hotter conditions, staple crops, forestry and fishing seem to be less sensitive to temperatures. The income effects of rainfall are more complex. Some findings indicate that more rainfall is beneficial in drier places but harmful in wetter places. Interestingly, the incomes of poorer households seem to be negatively affected by wetter conditions, while those of wealthier households are more impacted by drier conditions. This finding implies that the livelihoods of poor rural people are more vulnerable to severe rainfalls and flooding, which for example occurred at the end of 2013. The data indeed confirm that an increase in rainfall and wet months compared to 2012, which was also a wet year, had a negative impact on income growth between 2012 and 2014.

Bringing the variety of income effects from different types of weather variation together with the uncertainty about how weather conditions will be altered by climate change makes any effort to quantify the income and poverty impacts of climate change extremely challenging – not even considering that the weather sensitivity of income activities may change due to structural changes or adaptive responses. While future temperature increases due to climate change can be predicted with some level of confidence, there is less agreement on future changes in precipitation patterns. Yet variation between locations and between seasons is likely to increase (IMHEN and UNDP, 2015; ISPONRE, 2009; MONRE, 2009). Overall, however, it remains difficult to translate the global climate change scenario from the IPCC (2014) into localized impacts. While some locations could benefit from more favorable conditions, the overall variability of weather conditions is expected to increase with abnormal or extreme conditions likely to become more frequent and intense.

Notwithstanding the difficulties to quantify any future climate change impacts on rural incomes, the initial insights provided by this paper bring important implications for rural development in times of climate change. The findings demonstrate that high weather variation between years, seasons and locations is already the norm in rural Vietnam and that the incomes of most people including poor households are currently very sensitive to this variation. Consequently, rural households are already vulnerable to weather variation. Climate change could increase these vulnerabilities in many unpredictable ways. Hence it is important to make rural 26