Is Climate Change to Blame for the Ebola Outbreak?

From ecological destruction to changing weather patterns, man bears ultimate responsibility for the spread of deadly diseases.

AFP

Climate change is no longer controversial – it's happening. And some experts say it's responsible for the spread of Ebola to humans, as well as the increasingly frequent outbreaks of the deadly disease.

The connection between Ebola and ecological change has long been documented. As man invades pristine areas, he comes into contact with diseases carried by the animals he supplants (or eats). Some infect him.

To this day nobody knows where Ebola lurks in nature, or in the scientific argot, what animal is its "natural reservoir." Fruit bats have been maligned, but so far in vain. They definitely can carry Ebola, but there's no proof they're behind the infection of man.

Others suspect that the origin – at least in the Congo, not necessarily in the recent West African outbreak – is "bush meat," a euphemism for apes caught and eaten. Gorillas and chimpanzees, for instance, catch Ebola just as humans do, and if a man eats a sick ape, he'll get the disease.

Whatever the source, the more man comes into contact with animals, the more he's likely to catch animal diseases. And man's spread and climate change inevitably increase that interface between man and nature, where viruses lurk.

This is a general truth, not only for Ebola, which – with all due respect to jet travel and the latest panic – has not truly spread beyond central and western Africa. At least not yet.

Ebola and extreme weather

Scientists agree that the greenhouse gases already emitted by human activity will raise the planet's average temperature, acidify the oceans and much more. All of this is already changing the face of Earth.

Man has emitted so much carbon dioxide that even if he adds not one more molecule to the atmosphere, by the end of this century, the average temperature will rise by 1.8 degrees Celsius. The pessimistic scenario foresees an increase as high as 6.4 degrees, according to the Intergovernmental Panel on Climate Change.

The more temperatures rise, the wilder the weather is likely to become, scientists say.

But scientists remain divided on how the increase in temperature and other human activities will affect the planet. There are simply too many variables to make reliable predictions. One thing they're not divided on is that climate change and global warming are likely to increase the incidence and spread of disease.

A key element in Ebola outbreaks seems to be the more extreme weather. Hot weather is hotter, cold weather is colder, and storms are more powerful and last longer, even if scientists are still working on the why. 

In 2008, the New York-based Wildlife Conservation Society, listing 12 diseases that climate change will worsen, noted that Ebola outbreaks seemed to occur after atypical weather patterns, from unusually heavy rain to drought. These disrupt the normal living patterns, increasing the interface of man and nature.

For instance, if we take the fruit bat as a possible conduit for Ebola, heavy rain can make fruit trees more prolific, and hence the bats too. Drought results in poor fruit crops, leading the hungry bats to forage farther for food. Again the potential is created for greater interface between man and nature.

Man and malaise

So the more man comes into contact with nature (as he destroys it, usually), the more likely he is to be infected by something. Among the human activities debilitating the environment and increasing the potential interface between man and malaise is deforestation.

The denuding of the Amazon has provoked wails worldwide, but it happens in West Africa too. As man changes his environment, he displaces animals, again creating an interface that didn't exist before.

Yet another way climate change supports the spread of disease is that as the world warms, disease-carrying insects get happier and their habitat expands. A famous case is the mosquitoes carrying malaria and West Nile virus. Both are spreading but West Nile has gone global.

West Nile was first recognized in West Africa, where it was transmitted to humans mainly by mosquitoes (the vector) from birds (the primary host). But it was considered a disease of temperate zones.

The thing is, more and more of the world is becoming temperate and West Nile has gone all but worldwide; it's now considered an endemic disease throughout Asia, Africa, Australia, the United States and Europe.

Yet another climate-change-driven problem is food insecurity, which brings us back to bats and bush meat. There's no question that both carry Ebola, and that as climate change decimates crops, the people of West Africa resort to eating more wild animals.

Meanwhile, scientists are scrabbling to find an effective vaccine for Ebola, to discover its true reservoir and to contain the disease in West Africa, let alone the rest of the world. Right now, the world has a bad case of hysteria compounded by misinformation and an unfortunate propensity to ignore basic safety techniques when treating the sick.

Yes, the world has had good news this week: Nigeria announced that it's Ebola-free. But the long-term prognosis for the disease's spread isn't good. People are unlikely to learn how to use hazmat gear properly, even though the Centers for Disease Control and Prevention has just helpfully issued new directives.

At least Ebola isn't transmitted by mosquitoes like West Nile; it requires contact with the bodily fluids of an infected patient. But if it's true that extreme weather leads to outbreaks, the world had better brace.