The COVID-19 pandemic brought a worrisome glimpse into the potential consequences of looming health crises driven by climate change. Growing greenhouse gas (GHG) emissions intensify numerous climatic hazards, which can exacerbate human pathogenic diseases. However, our knowledge of the full extent of this risk remains unclear. A recent study published in Nature magazine looked into the impacts of ten climatic hazards on each known human pathogenic disease.
It’s important to understand the impact of climate change on these diseases as they have the capacity to not only cause illness and death but can also trigger broader socioeconomic consequences as we saw in the case of the COVID-19 pandemic which had far-reaching economic consequences including the second largest global recession in recent history.
The study notes the Coronavirus pandemic was not an isolated event and the burden of such diseases causes millions of deaths each year and an inexplicable amount of human suffering.
The authors of the study examined ten climatic hazards that are induced by rising GHG emissions; warming, droughts, heatwaves, wildfires, precipitation, floods, storms, sea level rise, ocean climate change and changes in natural land cover to see how they modifier in the transmission of pathogenic diseases.
First of all, climatic hazards are bringing pathogens closer to people as they disrupt the habitat of various species. Spillovers from viruses, for instance, were associated with wildlife, such as bats, rodents and primates, moving over larger areas foraging for limited food resources caused by drought or finding new habitats following wildfires.
Climatic hazards also facilitated the contact between people and pathogens. Heatwaves, for instance, by increasing recreational water-related activities, have been associated with rising cases of several waterborne diseases. Land use changes facilitated human encroachment into wild areas and brought people into closer proximity to vectors and pathogens, notes the study.
In addition to facilitating contact between people and pathogens, climatic hazards also enhanced specific aspects of pathogens, making them more resistant to these new climatic conditions. On the other hand, climatic hazards have also diminished human capacity to cope with pathogens by altering body condition.
All in all, the study found that more than half (58 per cent) of infectious diseases confronted by humanity worldwide have been at some point aggravated by climatic hazards. Empirical cases revealed 1,006 unique pathways in which climatic hazards, via different transmission types, led to pathogenic diseases.
“The sheer number of pathogenic diseases and transmission pathways aggravated by climatic hazards reveals the magnitude of the human health threat posed by climate change and the urgent need for aggressive actions to mitigate GHG emissions,” the authors of the study underline.
The study concludes that the human pathogenic diseases and transmission pathways aggravated by climatic hazards are too numerous for comprehensive societal adaptations, which means we have to go to the source of the problem: reducing GHG emissions.