Abstract ID: 3.12801 | Accepted as Talk | Requested as: Talk | TBA | TBA

Kilimanjaro (5895 m) is the largest free-standing mountain in Africa, famous for its diminishing snow and ice cover. There are strong linkages between ecosystems on the lower slopes (below 2500 m) and moisture availability higher up the mountain. Every day the strong equatorial sun heats the mountain, causing winds to rise upwards from the rainforest and form clouds/precipitation. At the highest elevations this adds snow to ice-fields, but lower down it provides river runoff for extensive agriculture in the cultivated belt below the rainforest. Unfortunately, long-term warming, along with local land-cover change (including deforestation), has led to drying over recent decades, rapid retreat of the summit ice, depression of the treeline, and several strong forest fires. The research team has operated a transect of 22 weather stations across the mountain from south-west to north-east since 2004. This is now the longest running transect to cover such a wide elevation range (~5000 m) in the world. It extends from savannah, through cultivated land and rainforest, up to the giant heather zone, alpine desert and summit ice cap. Thus, it offers critical information on how linkages between ecological zones are functioning in a warming world and on patterns of elevation-dependent climate change (where mountains warm at different rates to lower elevations). Analysis of two decades of temperature trends (2004-2025) shows an intensification of warming rate with elevation such that the highest sites are warming about twice as rapidly as some sites lower down the mountain. Humidity trends are more variable with both wetting and drying being observed in different locations. There are also contrasts between the two slopes, with the north-east side being much warmer and drier than the south-west slope for the same elevation. Kilimanjaro is a great field laboratory for understanding mountain geography because of its large elevation range, diversity of ecological zones, its local water supply importance and the population pressures on its lower slopes. Understanding local drivers of the elevation stratification of climate changes in this case (snow loss, forest expansion/contraction, cloud changes along slopes) can also be applied to mountains elsewhere.