It is enough to make hay fever sufferers weep: a potent new pollen is on its way to the UK.
Scientists are warning that climate change could cause a boom in ragweed, a highly allergenic plant that emits a billion grains of pollen in single season.
The most common cause of hay fever in the US, it arrived in Europe in the 1960s and has been spreading north ever since.
Extremely light and able to travel hundreds of miles on the wind, some ragweed pollen is already crossing the Channel from the Netherlands.
Millions more people across Europe may start suffering hay fever by 2060 as a result of climate change, a study has found (file photo)
Researcher Iain Lake said: ‘There are two elements to this. The first is that under climate change there is a greater probability of having the plant itself in the UK, although whether this occurs and to what degree depends upon measures taken to prevent its spread.
‘The second is that even if the plant does not occur in the UK, as it spreads across southern Germany and northern France it is likely that pollen will be transported, i.e. blown, to the UK.
WHAT IS RAGWEED?
Ragweed is a prolific pollen producer – one plant is capable of generating up to a billion pollen grains per season.
The weed is a far more potent allergen than grass and experts fear it could pose a serious public health problem as its wind-blown pollen is resilient enough to survive a mild winter.
Depending on the speed of dispersal, pollen levels in some locations could rise as much as 12 times, previous research found.
It invaded the European mainland in the 1960s – brought over in contaminated seed – and has been spreading north ever since.
‘The major increases in hay fever are likely to be in continental Europe but our models indicate that this is likely to start to become a problem in the UK by the 2050s.’
The rise of ragweed will also extend the hay fever season into the autumn and could also increase the severity of the allergy.
Dr Lake, an environmental scientist combined data on the changing climate, allergy levels and population centres to estimate how quickly ragweed will spread and how much of a problem its pollen will be across Europe in the coming decades.
He said: ‘Our research shows that ragweed pollen allergy will become a common health problem across Europe, expanding into areas where it is currently uncommon.
‘The problem is likely to increase in countries with an existing ragweed problem, such as in Hungary and the Balkans. But the greatest proportional increases will happen in countries including Germany, Poland and France.
Climate change will cause ragweed plants to produce more pollen – and this can spread across the continent. This pollen triggers a more severe allergic reaction than tree or grass pollen
‘Our projections suggest that ragweed pollen will persist from mid-September to mid-October across most of Europe.’
Writing in the journal Environmental Health Perspectives, Dr Lake said that control of ragweed is ‘essential for public health’.
However, ‘control of existing plants is difficult due to ragweed’s long-lived seeds, its ability to evolve herbicide resistance, and its capacity to re-sprout following cutting.’
Around one in four people in the UK suffers from hay fever, with grass pollen the main trigger.
Often dismissed as a minor inconvenience, the allergy can affect everything from sleep to productivity at work and school grades.