Impact of global climate change and desertification on the environment and society in Southern Centre of Vietnam (a case study in Binh Thuan province). Climate today and tomorrow: state of play and perception.

摘要

The Province of Binh Thuan is the driest area of Vietnam. It is felt as being affected by desertification processes that are mainly resulting from the ongoing „climate change‟, especially shortening rainfall. But has climate, and especially precipitations, really changed in recent years? Or is the recent increase of agricultural activities with higher water needs may explain such perception of a changing climate?In the collection of four papers presented hereafter, we try to answer to these questions.Yet, the first paper investigates recent trends in precipitation and temperatures using daily data from the weather station of Phan Thiet. It appears that the area did not experience any significant precipitation decrease (rainfall have, at the contrary, globally increased) but a very significant increase in temperature.The second paper focuses on future climate projections (that is 2046-2065 and 2081-2100 compared to historical data 1970-1999). It shows that the Province of Binh Thuan will face an increase of mean temperature of about 1.6°C (over 2046-2065) and 2.5°C (over 2081-2100) and an increase of extreme temperatures and extreme rainfall events. However, no significant changes about the evolution of the annual amount of precipitation were found. It also indicates that the dry season is likely to be longer in 2046-2065 owing to a delay in the onset of the rainy season (up to 15 days) accompanied by an earlier end of the rainy season (up to 30 days).The third paper explores recent land use and land cover changes in the Province of Binh Thuan. Comparisons of the land cover maps reveal that a steady growth in population has caused extensive changes of land cover throughout the area. The maps also indicate that the loss of woody land (forest) and the extension of irrigated area, combined with built-up encroachment, remains one of the most serious environmental problems today. Yet, results showed over the 12-year span, approximately 115,120 ha of forests were converted respectively to brush, irrigated area, cropland and built-up. This is an overall average decrease of approximately 9,594 ha of forested area per year. Based on the identified causes of these changes, we made policy recommendations for better management of land use and land cover. Such results show that water needs are always increasing due to the extension of irrigated areas.The last paper concludes with a case study of a fishing village disappearing as a result of shoreline erosion. It shows that the term “climate change” is misused probably because it is easier to blame a global issue rather than the local mismanagement of natural resources, the lack of land use planning and the nonexistence of policies focused on natural hazard management in the uncontrolled construction the seaside resort of Mui Ne.This reflexion about the wrong perception of climate change which may cause several economic problems could be extended to water availability which may not be sufficient to support recent developments of irrigated agriculture. Understanding current problems may help developing adaptation strategies in the next decades. Further research is needed to understand such perception of climate change, especially when knowing that future climate may be really affected by an increase of extreme rainfall events and an extended dry season.