“The 4°C scenarios are devastating: the inundation of coastal cities; the increasing risks for food production potentially leading to higher malnutrition rates; many dry regions becoming dryer; wet regions becoming wetter; unprecedented heat waves in many regions, especially in the tropics; substantially exacerbated water scarcity in many regions; increased frequency of high-intensity tropical cyclones; and irreversible loss of biodiversity, including coral reef systems. And most importantly, a 4°C world is so different from the current one that comes with high uncertainty and new risks that threaten our ability to anticipate and plan for future adaptation needs.”

— World Bank, Turn Down the Heat: Why a 4°C Warmer Planet Must be Avoided