In this blog post, we’ll examine how global warming affects our health, including the spread of infectious diseases and the rise in allergies.
We frequently encounter news about global warming on TV and the internet. These reports tell us that Arctic glaciers are melting, causing sea levels to rise, and accelerating the destruction of ecosystems. However, it’s not easy to directly feel the effects of global warming in our daily lives. For most of us, it’s limited to noticing that the weather feels hotter than usual and wondering, “Is this because of global warming?” Yet global warming has already become deeply embedded in our daily lives without us realizing it, and it is having various effects on our health.
Recently, dengue fever cases have emerged in Japan and other regions, bringing the disease back into the spotlight. Dengue fever is an infectious disease characterized by symptoms such as high fever, headache, muscle aches, joint pain, loss of appetite, and bleeding; while most patients recover, severe cases can be life-threatening. The disease is transmitted through the bite of a mosquito carrying the dengue virus and was historically confined mainly to tropical and subtropical regions. However, as average temperatures rise due to climate change, the range of mosquito habitats is gradually shifting northward, and accordingly, the areas where dengue fever occurs are expanding.
The spread of infectious diseases due to global warming is not a problem unique to Japan. South Korea is also not immune to this risk. The range of activity for certain mosquito vectors, including the Aedes albopictus mosquito that transmits dengue fever, is gradually expanding due to climate change, and rising temperatures are creating an environment even more conducive to mosquito survival and reproduction. Currently, cases of dengue fever imported from overseas continue to occur in South Korea, and surveillance and research into the possibility of domestic transmission are being strengthened in response to climate change. Furthermore, various mosquito-borne infectious diseases, including malaria, are known to be closely linked to climate change, making it difficult to consider South Korea a region that is completely safe from these diseases anymore.
Global warming affects not only infectious diseases but also allergies. At first glance, global warming and allergies may seem unrelated, but rising temperatures are closely linked to an increase in pollen—a major cause of allergies. As the global average temperature rises, the flowering season of plants is gradually advancing, and as a result, the period during which pollen remains in the air is also lengthening.
Plant flowering is regulated by temperature changes. Plants contain proteins called FLM (Flowering Locus M) and SVP (Short Vegetative Phase); normally, these two proteins form a complex that suppresses the expression of genes responsible for flowering. However, the SVP protein is sensitive to temperature changes and breaks down easily when temperatures rise. As a result, the complex fails to form properly, and the expression of genes responsible for flowering is promoted, causing flowers to bloom earlier. If temperatures rise faster than average, the flowering period is brought forward, and the duration during which flowers remain in bloom is extended. This leads to an increase in both pollen production and exposure time, which can exacerbate allergy symptoms.
In fact, domestic and international studies have confirmed that, alongside climate change, the pollen dispersal period is lengthening and pollen concentrations are increasing. Furthermore, allergic diseases such as allergic rhinitis and asthma are steadily on the rise, and pollen allergies are emerging as a significant health concern not only in spring but also in the fall. This is because rising temperatures are altering the flowering periods of some plants, gradually extending the duration of pollen exposure.
Global warming affects human health in various ways—not only through widely recognized phenomena such as rising sea levels and shrinking glaciers, but also through the spread of infectious diseases and an increase in allergies. The issue extends far beyond simply warmer weather or the flooding of some coastal areas.
Through advances in science and technology and ongoing research, new impacts of climate change on humans and ecosystems continue to be uncovered, and there are still many aspects that have not yet been fully elucidated. Therefore, to address climate change, efforts to reduce greenhouse gas emissions must be accompanied by measures to combat infectious diseases, strengthen healthcare systems, and conduct ongoing research and build a deeper understanding of changes in ecosystems.
