Climate Change Is Driving Up Pollen Emissions, Allergy Risks at A ‘Breathtaking’ Pace

The sudden increase in day temperatures in February and March, much before the actual onset of summer, has worried ecologists for years.

The seasons have shortened, and spring tends to arrive earlier than usual, impacting the cyclic growth of plants – a phenomenon often linked to climate change.

Now, a new study led by scientists from the US-based University of Michigan has shown that climate change could, in fact, drive plant pollen emissions to start 10-40 days earlier in the United States. According to the modelling study published in Nature Communications, these changes would be well-evident by the end of the century and could have additional negative effects on human health, with rising pollution levels.

Pollination is an essential ecological process that leads to plant fertilisation without which the human race and all of earth’s terrestrial ecosystems would not survive. However, it is also known to affect the health of at least 30 per cent of the world population, which is sensitive to pollen-induced respiratory allergies, and hay fever. Most of these are seen among children aged less than 18 years. The extension in the season for pollen-related allergies due to the rise in temperatures could seriously affect people struggling with allergies, the scientists explained.

The lead researchers, Yingxio Zhang and Allison Steiner, said they began the simulations to understand how climate change will alter plant pollen production and, consequently, seasonal allergies. The team combined climate data with socio-economic scenarios and developed a modelling approach to project changes in pollen emissions in the US by 2081-2100. They compared this data to a historical 20-year period (1995–2014) and projected that by 2081, pollen emissions could start up to 40 days in advance and may last 19 days longer, increasing the annual pollen emissions over the US by at least 16–40 per cent.

The team further added that a rise in pollution levels in the coming years could worsen the problem. “These findings are a starting point for further investigations into the consequences of climate change on pollen emission patterns and subsequent health implications,” the paper read.

While the research is modelled on the US, scientists in India, too, have expressed concerns over early spring in the country and showed how it has impacted the flowering season of plants in multiple studies. Over the years, the country has seen a sudden rise in temperatures towards the end of February, and the transition from winter to summer is not as gradual as it should normally happen in the earth cycle.

As a result, the shedding of leaves starts early, and trees like Delonix, popularly known as Gulmohar, which normally start flowering in June have begun to flower in March because of warmer temperatures.

It is mid-March, and maximum temperatures are already 5.1°C above normal at most places over Himachal Pradesh, Konkan & Goa, Jammu-Kashmir, Ladakh, Muzaffarabad, West Rajasthan, Assam-Meghalaya and Saurashtra-Kutch.

The India Meteorological Department has also sounded a heatwave alert for the Saurashtra-Kutch region of Gujarat, south-west Rajasthan, West Madhya Pradesh, Konkan-Goa, Odisha as well as coastal Karnataka.