Land degradation is a worldwide problem caused by non-sustainable management of farm and grazing lands. Strongly reduced vegetation cover leads to eroded, low quality soils, decreased rainfall infiltration and groundwater recharge, increased runoff loaded with sediments and an overall deterioration of the ecosystem services provided by the area affected. Especially in semi-arid areas, land degradation interacts with climate change, each reinforcing the other. As a result, livelihoods of people living in degraded areas, as well as those living downstream -hydrologically and meteorologically, are negatively affected.
Land restoration, or 're-greening', tries to remedy such adverse effects, sometimes explicitly aiming at climate restoration too. Potentially positive climate effects of re-greening, such as reduced temperature extremes, enhanced total rainfall and/or less variable rainfall, have been relatively little quantified. It is not clear if negative climate effects following degradation are simply reversible upon restoration, or not. Also boundary conditions for successful climate restoration need to be identified. The PhD candidate will address such issues in this research, funded by the Africa Water Foundation.
The Water Systems and Global Change group (
www.wur.nl/wsg ) of Wageningen University & Research has built up a considerable track record in studying interactions between hydrology, land cover and land use, and climate (change). We do this in the context of deforestation / agricultural expansion, large scale irrigation, urbanisation in both tropical and temperate climates worldwide.
As a PhD candidate, you will work on the following research topics (relative weight to be determined based on your interest and qualifications):
- Making an inventory of existing re-greening projects around the world and in Africa in particular, with the aim to construct a chrono-sequence.
- Analysing observed first and second order hydro-climatic effects of re-greening as a function of project scale and - maturity, and of base line physiographic characteristics of the region.
- Identifying causal processes in the soil-vegetation-atmosphere continuum responsible for the observed effects or the lack thereof; analyse synergies and trade-offs between the small and large hydrological cycle
- Identify design rules for land restoration projects that maximize the chance of positive climatic effects
Your work will consist of literature studies, analysis of satellite observed and in-situ meteorological data, as well as numerical modelling of land-atmosphere interactions. You will be member of a larger team of researchers within and outside Wageningen UR working on this topic, and have strong interaction with various stakeholders (governmental, NGOs, etc.) associated with re-greening projects around the world.
Your project results will be disseminated through papers in peer reviewed journals (as a basis of your PhD thesis) and conference proceedings, but using also popular media is encouraged.