The pollen season extends from the end of winter to autumn.<br />But the global warming would be at the origin of the increase of the duration and intensity of this season.<br />A number of smaller scale studies, usually conducted in greenhouses, had indicated strong links between temperature and pollen levels.<br />Our work highlights this link on a continental scale, and establishes an explicit correlation between pollen levels and climate change driven by human activities.<br />"Climate change is not something distant and future. Its consequences are already very visible." William Anderegg, lead author of the study<br />The study was conducted from 60 monitoring stations in North America between 1990 and 2018.<br />Conclusions: In the United States and Canada, the pollen season starts up to 20 days earlier and can last up to 8 days longer.<br />Allergies would also be also more intense: The concentration of pollens would be up by 20.9% over the period.<br />However, the authors of the study noted regional differences.<br />This could depend on:<br />- the precipitation rate, <br />- the number of days of frost<br />- and the concentration rate of carbon dioxide<br />Note: Climate change accounts for 50% of the lengthening of the allergy season but only 8% of the increase in pollen levels.<br />Pollen can cause asthma, allergies or respiratory problems.
