Currently about one billion people, or 14.5% of the world’s population, live in extreme poverty. The prospective impacts of climate change may be a serious threat to the goals of ending poverty by 2030 and promoting shared prosperity.
To enhance the understanding of such threats, a team of researchers (David Wheeler, Mainul Huq, Md. Moqbul Hossain and myself) recently analyzed the potential effects of climate change on land degradation, livelihood of poor rural households, and the responses of those households, in coastal Bangladesh. Our study focused on areas of coastal Bangladesh where the incidence of poverty is very high (both, in absolute terms as well as relative to the rest of the country), and where residents already have experienced widespread inundation and salinization of soil and water. We were looking to quantify the impacts of these events on household composition through migration decisions, and the effects they have on household economic welfare.
Earlier research had indicated that soil salinity in coastal Bangladesh and river salinity in the southwest coastal region have increased over time, and very likely will increase more with climate change. Moreover, in Bangladesh a dense population combined with land scarcity and inflexible land tenure conditions have contributed to the commonly observed migration of working-age (mostly male) family members away from households in the most threatened coastal areas (close to the sea, low in elevation and highly saline at times of the year), where families then survive on their remittances.
The analysis looked at the impact of inundation risk and salinization on household composition, economic welfare, and poverty. One part of the study linked the percentage of resident working-age individual (males and females) in households to travel time to the nearest urban center, soil salinity and two components of inundation risk: distance from the coast and elevation. Another part evaluated the probability that the households close to the sea, low in elevation and with saline land are in the lowest 20% of Bangladesh’s national wealth distribution.
For this research, we assembled a number of databases and satellite maps and applied state-of-the-art spatial estimation methods to these data. The information on household demographics and economic welfare was acquired from the Bangladesh Demographic and Health Survey.
Our findings indicate households subject to high inundation and salinization threats have out-migration rates for working-age adults (particularly males), dependency ratios, and poverty incidence that are significantly higher than their counterparts in non-threatened areas. The critical zone for inundation risk lies within 4 km of the coast, where about 8% of the population of Bangladesh currently resides, with lesser impacts observed for coastal-zone households at higher elevations. About 92% of the land in the 4 km coastal band is exposed to inundation and salinization threats.
To illustrate the magnitude of the threats, we compared results when salinity, inundation risk and market access are switched from their least harmful to most harmful projections within the 4 km coastal band. In this case:
- Reallocation of labor to outside earning opportunities leads to 53% and 22% decreases in resident working-age males and females respectively.
- The ratio of old and young dependents to working-age adults increases by 160%.
- The poverty impact is also striking: the probability of being in the lowest one-fifth economic status rises six-fold between least and most harmful projections, from 8% to 56%.
Furthermore, we find that if we set all the determinants of risk impact (distance to urban center, soil salinity, and elevation within the 4 km coastal band) to their median values, the probability that a household is in the lowest one-fifth economic status is 16%.
In summary, our results paint a sobering picture of future prospects for households in coastal Bangladesh - those households threatened by inundation and salinization, particularly households that are relatively isolated from market centers. They respond by “hollowing out”, as economic necessity drives more working-age adults to seek outside earnings. And those left behind face a far greater likelihood of extreme poverty than their counterparts in less-threatened areas.
With a virtual certainty that sea-level rise will continue beyond 2100 even if greenhouse gas emissions are stabilized today, the families in coastal Bangladesh are already on the “front line” of climate change. Their adaptation foretells future decisions by hundreds of millions of families worldwide who will face similar threats by 2100. Our powerful results for market access suggest that infrastructure investment to improve access – especially road improvement – may offer a promising option. At present, isolated settlements in the coastal region face travel times to market centers as much as nine hours. Our findings indicate reduction in travel times for isolated settlements by 2 1/2 hours would significantly improve their economic welfare. These benefits of increased mobility capability are enlarged by the threat of climate change but exist even in its absence, making such investments an attractive low-regret option.
Funding for our research has been provided by the Knowledge for Change Trust Fund.
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