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

In the equations above, TFR, climatic variables and GDP per capita are measured in logs. Δ denotes first differences. σ refers to the constant. γj, ηj, ξm are the parameters that denote the short-term elasticities. In Eq (1), ECTt−1 refers to the error correction term, representing the long-term relationship among the TFR, climatic indicator, and GDP per capita. λ is the adjust- ment parameter representing the speed of convergence to the equilibrium path. The error cor- rection term is specified in Eq (2). α and β reflects the long-term relationship of TFR with respect to climatic indicators and GDP per capita. We first test the variables for their unit- roots to check their stationarity through the Augmented Dickey-Fuller test. Second, we test for cointegration using the Johansen test. Finally, we run ECM models. We use the software pack- age of STATA 16 for path analysis and ECM modelling. Results Descriptive statistics Bangladesh’s fertility trends from 1966–2015 are shown in Fig 1. The rapid decline of fertility in the last five decades in Bangladesh is, indeed, a historic record in the demographic transi- tion. TFR declined from around 7 (children per woman) in 1966 to 2.1 (children per woman)– the replacement level–in 2015. Although the extent and rapidity of the fertility decline have been very impressive, the pace of decline could be influenced by climate change and its adverse effects on food production in Bangladesh. Fig 2 shows agricultural production over time. Over this period, production of the main crops–rice, wheat, and pulses–in Bangladesh has been

increasing, except in 1971, 1972, 1974, 1976, 1994, and 2004. The reduction in crop production in these years could be attributed to the effects of war in 1971–1972, the effects of drought in 1974 and 1976, and crop losses due to flooding in 1994 and 2004, respectively. Despite the increase in food production with the advanced use of technology, Bangladesh still remains food insecure, which could be exacerbated by climate variability changes. Figs 3 and 4 show the annual average maximum and mean temperature, respectively. Although highly fluctuating, the temperature has followed a slight upward trend. A linear esti- mate shows that the maximum temperature increased at a rate of 0.016 degrees Celsius per Fig 1. Total fertility rate in Bangladesh for 1966–2015. https://doi.org/10.1371/journal.pone.0258196.g001 PLOS ONE Climate change, food security and fertility PLOS ONE | https://doi.org/10.1371/journal.pone.0258196 October 21, 2021 6 / 18