The burden of disease associated with aeroallergens is anticipated to grow due to climate change . The incidence of pollen allergy and associated allergic disease increases with pollen exposure, and the timing of the pollen season and pollen concentrations are expected to change under climate change . The overall length of the pollen season and total seasonal pollen counts/concentrations for allergenic species such as birch  and ragweed  are expected to increase as a result of CO2 fertilisation and warming, leading to greater sensitisation . Changes in pollen levels for several species of trees and grasses are projected to increase annual emergency department visits in the USA by between 8% for RCP4.5 and 14% for RCP8.5 by the year 2090  with the exposure to some pollen types estimated to double beyond present levels in Europe by 2041-2060 . The prospect of increases in summer thunderstorm events under climate change  may hold implications for changes in the occurrence of epidemic thunderstorm asthma . Similarly, projected alterations in hydroclimate under climate change may bear implications for increased exposure to mould allergens in some climates .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report