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Connections between disease and climate change

Colin Cargill

Connections between disease and climate change

Introduction and background


The world is in the midst of a severe disease pandemic which has come when creation is already in the midst of another major crisis, climate change. While climate change may have no direct connection to the emergence of the current pandemic, it is a timely reminder that humans are a vulnerable species like any other species, especially when placed in an unnatural or sub-optimal environment.


With the current pandemic, it seems that the unnatural environment created in a wet market, with sub-optimal hygiene and a mix of animal species not normally in close contact, enabled a virus to jump species. While climate change appears to have played little part in creating this environment, climate change is creating a sub-optimal environment for many species through a range of factors such as warming oceans, changes in the relationship between temperature and altitude and more severe and extreme weather events.


Both disease pandemics and climate change are complex and multifactorial events that are influenced by how humans live and relate to each other. And while climate change cannot be directly linked to the current pandemic, it can be linked to many other emerging diseases of both plants and animals, including humans.


Climate change is a key driver in the emergence of new diseases in specific geographical regions where those disease have not previously existed. Extreme weather events, which are increasing as a result of climate change, create conditions conducive to clusters of insect-, rodent- and water-borne diseases. Accelerating climate change carries profound threats for public health and society and COVID-19 provides us with a wake-up call to observe and act on what is already occurring.


Weather patterns have also been identified as a factor in disease outbreaks. These include the timing of cholera epidemics in Peru and Bangladesh; ciguatera (a toxin associated with fish) in the Pacific islands; Ross River virus epidemics in Australia; and dengue and malaria epidemics in several countries. Many diseases have a seasonal pattern and hence changes in climate will affect the seasonal patterns through lengthening transmission seasons and affecting environmental and demographic thresholds that underlie seasonal outbreaks.


One commonality between the current pandemic and the climate change crisis is our failure to heed warnings. Internationally recognised epidemiologists, microbiologists, and human and animal health experts have been expressing their concerns about the emergence of new diseases and changes to the patterns of existing diseases for decades. The last 50 years has provided several examples. Similarly, climate scientists, geologists, meteorologists and others have been making prophesies about what will happen if humans fail to heed the signs and change how we live and pollute our environment. One example being the continued reliance on fossil fuels to maintain our lifestyle.


Perhaps an anonymous quote says it all – “healthy birds do not soil their nests – but humans have been soiling their nest since the industrial revolution!”


Lessons learned


The COVID-19 pandemic has shown us the importance and impact of individual power. By managing our social behaviour, we were able to slow the spread and flatten the transmission curve. Individual actions can be effective and by heeding advice and living responsibly we can flatten (slow) the global warming curve.


It has demonstrated how connected we are, not just to each other, but as different interdependent species sharing the Earth. In the words of Norman Habel AM – We are related not only to all living beings but to all the factors and forces of the planet.


The need to make the welfare and safety of people our number one priority has been clearly demonstrated. Prioritising expenditure on people and creation ahead of weapons and coal will help secure our future. Equipping and staffing health facilities and providing support to those who are homeless and who become unemployed is even more important than equipping our armed forces.


The fundamental importance of respecting science and listening to scientists as they interpret data, and make short and long-term recommendations to Governments, has been clearly demonstrated.


It has also shown us that understanding the causes of a crisis are as important as modelling the economic consequences and financial impact. Failure to act can end up being more costly.


The use of technology to maintain contact and communicate with our family, our networks, and our business colleagues has provided a model for reducing the cost of doing business by reducing travel costs. As a church it has also given us new ways to bring people together for meetings and discussion groups without the need to travel large distances.


Importantly it teaches us to be vigilant, caring and concerned for our neighbour, whatever their faith, their ethnicity or their species.



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