Respiratory illnesses may increase with global warming

Respiratory diseases, such as hay fever and asthma, may increase in the future due to global warming, warns a report published in this month’s Annals of Allergy, Asthma and Immunology, the scientific journal of the American College of Allergy, Asthma and Immunology (ACAAI).


Global warming has produced a 29% increase in CO2 levels since pre-industrial times, which is likely to double again between 2050 and 2100, says the report. This expectation has given rise to the fear of greater production of airborne allergens such as pollen, through quicker and more abundant growth of plants, which may result in more cases of respiratory ailments, says the report.

Scientists at Harvard University and Harvard Medical School carried out a study on the pollen-producing ragweed plant. Plants were grown under both elevated and ambient CO2 conditions; pollen production was compared from both plants. The experiment showed that pollen production was 61% higher in plants that were exposed to higher levels of CO2.

This experiment reflects the findings of a recent study, which also highlighted the potential danger to public health by rising CO2 levels in the atmosphere.

Despite the possible health dangers from warming of the earth, Dr Peter Wayne, a member of the study team, states that it would be “challenging to accurately predict the threat to public health caused by CO2-stimulated pollen production”.

The study notes that the size of pollen grains was not affected, despite the plant’s high CO2 exposure. It is therefore unknown whether the ratio of allergenic proteins per grain is maintained with the increase in quantity of the grains. If it is, then there may be “a pressing need to modify factors within our control”, according to Dr Richard Weber from the National Jewish Medical and Research Centre. The same research team is doing further experimentation to qualify this.

“A lot more prevention is needed in terms of the causes of CO2 production,” Dr Paul Epstein, a researcher on the study told edie. He is concerned over the increasing evidence that shows global warming as a main contributor to respiratory illness, such as asthma. A report published earlier this year also linked the cause of asthma to ozone levels; ground level ozone is also on the increase with global warming (see related story).

This study adds more weight to the theory that respiratory disease is linked to environmental factors. Dr Epstein says the ‘precautionary principal’ must be adopted, by using clean energy, for example, to destabilise the earth’s climate and decrease the risk to human health.

Story by Sorcha Clifford.

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