Kilimanjaro is changing. There has been extensive deforestation. The summit ice-fields are retreating. The water supply on the lower slopes of the mountain is becoming more unreliable with more flash flooding and more periods of drought. The main cause of the summit ice retreat is that the climate is becoming drier, with less precipitation (hence accumulation of snow), and fewer clouds meaning more sunlight which causes intense sublimation and hence ablation.
The reasons for drying, however, are not well understood. They are believed to be a combination of free air changes due to changes in the Indian ocean upstream to the east, and local-scale land use change (such as deforestation) which may dry out the air locally.
Because the mountain is in the tropics, the sun is strong and it heats the mountain each day. This causes upslope winds that help transport moisture from the rainforests on the lower slopes to the summit region where it is deposited as snow (or at the very least forms cloud that protects the ice fields from sunlight). The upper air itself is normally extremely dry, so it is possible that deforestation could in theory cause ice field decline.
Unfortunately, although we have much high publicity research focusing on the ice-field decline, there is no field data on the slopes of the mountain that measures climate, although high profile and well-funded international campaigns have looked at the mountain summit in isolation. There are also lots of computer models of Kilimanjaro's climate and the effects of deforestation but they have no data against which to validate their simulations.
This research proposes to fill this gap by collecting field observations of temperature and moisture on both the windward dry north-east slope and the lee forested south-west slope, expanding on data already collected by the research team since 2004. The funding will allow collection of two years of data on the south-west slope (10 years in total), and two years on the drier north-eastern slope. As well as the comparison between slopes, we will collect data from subsidiary studies at a more local scale (at given elevations on the south-west slope) examining the contrast between vegetated and deforested/unvegetated locations.
We will be able to compare our results with free-air temperatures and moisture at the same elevations (from reanalysis products which are based on weather balloon records) which will show us how the mountain surface itself is influencing the climate.
We will be able to compare the two slopes to quantify the large scale effect of vegetation (the south-west slope has healthy forest cover but the north-east slope does not) and local scale effects by comparing vegetated/non-vegetated readings on the south-west slope.
We will be able to use the differences we obtain to reconstruct mountain climate back in the past, and also to compare/validate the computer models that are attempting to simulate the effects of land-use change on the mountain.
In 2015, UN member states agreed to 17 global Sustainable Development Goals (SDGs) to end poverty, protect the planet and ensure prosperity for all. This project contributes towards the following SDG(s):