Climate change, if left unaddressed, could drive up the spread of infectious diseases and increase the number of respiratory-related deaths, waterborne infections, allergies and mental health issues in European nations, according to a report by scientists from 27 national European scientific academies.

"Climate change is already contributing to the burden of disease and premature mortality," said the report by the European Academies Science Advisory Council, or EASAC. "Without prompt and effective action, the problems are forecast to worsen considerably."

Among the most vulnerable groups are the elderly, children, people with preexisting medical conditions, migrants and other marginalized groups, the report said.

EASAC is the vehicle that European scientists use to report findings and advise relevant policymakers on needed actions.

Health risks will increase as climate change intensifies through a range of pathways, the report explained, including through increased exposure to high temperatures and extreme events such as floods and droughts, air pollution and allergens.

Climate change could increase the occurrence of infectious diseases including mosquito-borne, foodborne and waterborne ones to humans and animals, the report said.

Instances of diarrhea may climb following heavy rainfall and flooding, and higher temperatures could increase antibiotic resistance for pathogens such as E. coli. Warmer temperatures could drive up the occurrence of food poisoning from salmonella, and when winter temperatures do not get cold enough to kill mosquitos, global warming could drive up the number of West Nile virus infections. The report urged policymakers to strengthen communicable disease surveillance and response systems given the changing climate.

EASAC also found that moving to a zero-carbon economy could potentially prevent hundreds of thousands of premature deaths annually in Europe and about 3.6 million deaths globally that are caused by air pollutants emitted from fossil fuel-fired power plants. Seven million babies in Europe are living in areas where air pollution exceeds the World Health Organization's recommended limits, and such exposure may affect brain development and cognitive function, EASAC said.

To realize the benefits of a zero-carbon economy, the report said the EU "must ensure integration of climate and health policy options with other policy, in particular for the circular economy; for delivery of sustainable, healthy diets; for tackling air pollution; and for ensuring that development aid focuses on climate change adaptation and mitigation priorities."

Allergies could also be exacerbated, with ragweed allergies expected to more than double in Europe to affect about 77 million people by 2060 under an extreme global warming scenario. The report cautioned that climate-related flooding, storms, wildfires, and heat waves can also impact mental health.

"Mental health effects include post-traumatic stress disorder, anxiety, substance abuse and depression," the report said. It cited a 2018 study showing an association between higher temperatures and increased suicide rates in the U.S. and Mexico.