The link between climate change, food security and fertility: The case of Bangladesh

followed by a description of the data and methodology used in the analysis. Then, the results regarding the impact of climate change and crop production on fertility are presented. Finally, a concluding section discusses the implications of the main findings and provides recommen- dations for further research. Conceptual framework Impacts of climate change on food security Crop production in South Asian countries is likely to be most affected by climate change. For example, a temperature increase between 1.0˚C and 3.0˚C could reduce rice production in Punjab by 3–10% [45]. In Tamil Nadu, rice production decreased by up to 41% in response to a 4˚C temperature increase [46]. In Pakistan, Ali et al. found that maximum temperature was negatively associated with wheat production, while the effect of minimum temperature was positive and significant for all crops (wheat, rice, maize, and sugarcane). Moreover, the effect of rainfall on crop yield was negative except for wheat [47]. Esham et al. also found in Sri Lanka that temperature is negatively associated with maize yield, while rainfall is positively associated with maize yield [48]. In Indonesia, Levine and Yang found that more rainfall in a year increases rice production [49]. This literature suggests that temperature has adverse effects and rainfall has positive effects on South Asian countries’ major crop production, indi- cating that their primary crop production is highly susceptible to climate change and variability. In Bangladesh, agriculture absorbs about 44% of the workforce [50]. 76% of population live

in rural areas, and 90% of them are directly involved in agriculture. The net crop income is sensitive to climate changes [51]. Despite technological advancement, the climate still plays a crucial role in agriculture, where temperature and rainfall are the key determinants of crop production [52]. In this study, the analysis includes the most three major crops- rice, wheat, and pulses. As for rice, the climatic impact varies across different types of rice [53–55]. Sarker et al. evaluated the effects of climate change (e.g., temperature and precipitation) for three major rice crops (Aus, Aman, and Boro) in Bangladesh and found significant effects of climate change on rice yield. Their findings revealed that maximum temperature has positive effects on Aus and Aman rice and negative on Boro; the minimum temperature has adverse effects on Aman and positive on Boro; rainfall has positive effects on Aus and Aman [53]. The produc- tion of wheat is susceptible to temperature in Bangladesh [56, 57]. Links between climate change, food security and fertility Climate change, such as changes in precipitation patterns and frequent temperature fluctua- tions, can affect population dynamics through fertility behaviour [35, 58]. There are some recent studies on how fertility rate or outcome responds to climate shocks [59–62]. For exam- ple, higher temperatures reduce birth rates about nine months later [59]. Lam and Miron found that a 1˚C increase in monthly temperature would lead to nearly 1% fewer births nine

months later for the white population (62). Similarly, a 1˚C increase in summer temperature leads to 1% [63], 0.5%, or more [64] fewer births nine months later in many U.S. states. Not only temperature but also precipitation is related to fertility [62]. A study of rural com- munities in Mexico found that fertility–in the years following an increase in precipitation–was 1.14 times higher for dryland communities than for wetland communities. This implies that the previous year’s precipitation is an important factor in fertility timing, especially for dryland communities. The author explains that during a drought period in arid areas, households may prefer short-term migration to find work in the absence of livelihood opportunities. Once environmental conditions improve after above-average rainfall, household members were PLOS ONE Climate change, food security and fertility PLOS ONE | https://doi.org/10.1371/journal.pone.0258196 October 21, 2021 3 / 18