What 1.5°C warming means for hotspots: Insights from CARIAA
CARIAA’s insights refer to the specific effects of temperature increases in climate change hotspots. By 2025, the 1.5°C global warming threshold will be breached, and this will have profound effects for the more than 1 billion people living in climate change hotspots such as deltas, glacier-fed mountain basins, and in semi-arid lands throughout the Global South. CARIAA, co-funded by the UK’s Department for International Development and IDRC, has provided unique contributions to global climate knowledge about the impacts of this warming.
When the IPCC first called for a special report on the impacts of 1.5 °C warming, the existing literature was sparse and lacked a regional focus. CARIAA scientists recognized this knowledge gap and collaborated to investigate the ways in which warming of 1.5°C and 2°C would impact specific hotspots. Even with ambitious emissions policy interventions, CARIAA findings show that warming in hotspots is expected to reach the 1.5°C and 2°C limits within a decade.
What impacts can be expected?
With 1.5°C warming, at least one-quarter of the ice on the Himalayan mountains today will be lost, affecting 13% of the world’s population. These changes will lead to seasonal shifts in water availability and may have serious consequences for mountain and river basin communities, where approximately 910 million people depend on the glacier and snow-melt water as a key water source for livelihood-related activities.
Semi-arid lands will also experience high variations in precipitation, with significant impacts on power production, agriculture, and health. These impacts will lead to more frequent water shortages in today’s urban and agricultural supply systems. At a global warming of 1.5°C, 14.3 million livestock holder families in East Africa will be affected by the 30°C cattle production threshold, above which productivity falls. In Kenya alone, 1.7 million heads of cattle will be lost due to these conditions, an equivalent of US$680 million today. Even higher cattle losses are expected at 2°C global warming.
Due to annual variability, the impact in low-lying deltas will not be measurable until the 2040s, when the area of land inundated by flooding is expected to increase by 2.5 times. Monsoonal flooding will become more frequent and widespread under climate change, affecting the large populations who call deltas home.