With the support of climate-system models and results of climate research, the consensus is that greenhouse gas emissions generated by human activity will cause climate change. Moreover, it is proved that the recent average temperature increase of 0.5°C is partly due to such human-driven emissions. This leads people to think about the negative effects of climate change, and in this article, we will focus on how climate change impacts human health, as it is something directly related to everyone.
With climate change comes many environmental effects such as extreme weather events, effects on ecosystems and particular species, sea level rise, and environmental degradation. These environmental effects also contribute to several different health effects.
Extreme weather events such as floods, storms, cyclones, and bushfires can cause thermal stress including illness, injury, or even death. Extreme weather also affects our food, which in turn affects our health. Climate change can cause microbial proliferation including food poisoning such as Salmonella spp infection (one of the leading causes of acute diarrheal disease), unsafe drinking water, and changes in vector-pathogen host relations. Infectious disease’s geography or seasonality such as malaria, dengue, tick-borne viral, and schistosomiasis. Additionally, climate change, as well as sea level rise, brings about impaired crop, livestock, and fisheries yields, leading to impaired nutrition, health, and survival.
The environmental degradation resulting from climate change leads to displacement and a loss of livelihoods. This in turn leads to poverty and adverse health effects, for example, poor mental health, infectious diseases, malnutrition, and other physical risks. In fact, models of climate change effects on cereal grain yields indicate there will be a 5 –10% increase in the global number of underfed people.
For deeper analysis, a question may be raised: can we attribute climate change to some fraction of the health effects associated with a particular climatic event? For example, the probability of the occurrence of the severe European heatwave of 2003 was estimated to have been doubled by the underlying warming trend largely induced by human activities. Simple arithmetic therefore suggests that half the excess heat was due to that warming. Thus, we can infer that approximately half of the deaths during the 2003 heatwave were due to that underlying anthropogenic contribution.
We must also take into consideration the future risks of climate change. Firstly, heat-related problems are going to become more severe. This is because even small changes in temperatures, along with a shift in mean temperature, can greatly increase the frequency of extreme heat. Similar reasoning applies to other meteorological variables. Because populations in high-income countries are predicted to age substantially over the coming decades (the proportion aged over 60 years increasing from 19% to 32% by 2050), and with a trend towards urbanization in all countries (projected to increase from 45% in 1995 to 61% by 2030), a greater proportion of people in all countries will be at risk from heat extremes in the future, even without substantial climate change. In Australia, for a medium-emissions climate change setting in 2050, the annual number of deaths attributable to excess heat in capital city populations is expected to increase by 50%, up to 1650 people.
Furthermore, climate change can affect the potential incidence, seasonal transmission, and geographical range of various vector-borne diseases. These diseases include malaria, dengue fever, and yellow fever (all mosquito-borne), various types of viral encephalitis, schistosomiasis (water-snails), leishmaniasis (sand-flies: South America and Mediterranean coast), Lyme disease (ticks) and onchocerciasis (West African river blindness, spread by black flies).
Beyond the specific and quantifiable risks to health are indirect and knock-on health effects due to the social, economic, and political disruptions of climate change, including effects on regional food yields and water supplies. The conflicts and the migrant and refugee flows likely to result from climate change would, typically, increase infectious diseases, malnutrition, mental health problems, injury, and death.
In conclusion, a wider recognition of the health risks caused by climate change should be established. Efforts should be made to disseminate this information to raise awareness of the importance and severity of climate change. Resolution for climate change is urgently needed – hopefully, more and more people can realize the urgency and make efforts.
Vocab:
Anthropogenic: environmental change caused or influenced by people, either directly or indirectly.
Vector-borne diseases: human illnesses caused by parasites, viruses and bacteria that are transmitted by vectors.
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