Malawi, one of the poorest countries in the world and located south of the Sahara Desert, has been in the midst of extensive deforestation for the past 30 years.
The research team of Associate Professor Hisahiro Naito of the University of Tsukuba and Annie Mapulanga, a graduate of the same university and a staff member of the Ministry of Natural Resources of Malawi, have now used GPS information and satellite data from the Malawi household survey. We attempted to quantify how deforestation and rainfall within a 7.5 km radius of a household affect access to safe water.As a result, a 1 percentage point reduction in forest area has reduced access to safe water by approximately 1 percentage point, and logging over the last decade (10%) has provided access to safe water. The impact was shown to be equal to a 14% reduction in current rainfall.
Previous studies have argued that deforestation does not increase river water volume and reduce access to water, as forests absorb water and release it into the air.However, deforestation reduces the penetration of rainwater into the soil, leading to land erosion, resulting in turbidity in rivers and lakes.If deforestation leads to higher water purification costs in poor developing countries, it is an important policy issue.
Therefore, in this study, we aimed to identify the causal relationship between deforestation and access to safe water using statistical methods.As a result, it became clear that past deforestation has a considerable impact on residents' access to safe water.
The results of this study, conversely, mean that a 9% decrease in rainfall in the future can be offset by a 14% increase in forest volume.This can be said to indicate that forests play an important role in preparing for future climate change.
Paper information:[Proceedings of the National Academy of Sciences of the United States of America] Effect of deforestation on access to clean drinking water
