Population growth plays a major role in projected future water stress . Combining projected aridity change  with population projections derived from SSP2 shows that the SIDS with high projected population growth rates are expected to experience the most severe freshwater stress by 2030 under a 2°C warming threshold scenario . For several SIDS , increasing aridity change is a prominent exacerbating factor, but for others  population growth is the main factor. An increase in temperature of 1ºC  could result in a 60% increase in the number of people projected to experience severe water resources stress in the period 2043-2071 . Research on Jamaica concluded that the ability of rainwater harvesting to meet potable water needs between the 2030s and 2050s will be reduced based on predicted shorter intense showers and frequent dry spells .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report