In 2015, on the steppes of Kazakhstan, at the crossroads of Asia and Europe, more than 200,000 critically endangered saiga antelope suddenly died in a span of just three weeks. In less than a month, then, 80 percent of the local population was wiped out, which also meant that more than 60 percent of the animals’ global numbers had vanished.
In a report that was published in Science Advances in January 2018, researchers stated that a bacteria that was already present in the antelope was triggered and became harmful because of a period of unusual heat and humidity in the 10 days leading up to the mass deaths.
The saiga antelope aren’t the first animals to be severely impacted by a warming world. In 2016, the first mammal to go extinct due to climate change—a small rodent—was officially declared.
The runaway train that is climate change is causing us to lose animals at an unprecedented rate. But it seems that we aren’t paying attention, and I wonder: when will we start to miss the species that are disappearing before our eyes?
Climate change is the trigger
A bacteria called Pasteurella multocida type B lives in the tonsils of almost all saiga antelope. Usually, this bacteria causes no problems for the animals, and it alone is not enough to explain the recent mass fatalities. But when unusually warm weather occurs, the bacteria grow to toxic levels, causing a form of blood poisoning called hemorrhagic septicemia.
This link between climate change and saiga antelope deaths was discovered by a research team at the Royal Veterinary College at the University of London. Scientists there developed models that looked at other near-extinction, saiga antelope events—one in 1981 and another in 1988—when the animals are also believed to have died because of hemorrhagic septicemia. Environmental factors, such as rainfall, temperature, wind and the state of the vegetation, were compared. It was found that high humidity—over 80 percent—was the common thread that tied the three mass-death events together. The humidity was significantly higher in the 10 days before the deaths started at die-off sites than it was at sites where saiga antelope didn’t die en masse.
It’s now thought that Pasteurella multocida type B is sensitive to the warm, moist air that the animals breathed in. That makes sense because bacteria in the tonsils are quite close to the environment of the air, quickly responding to changes in the atmosphere. And that triggers them to start growing. The saiga antelope that were not in the same location as those that died most likely survived because they were in areas not affected by the high temperatures.
The fact that Pasteurella multocida type B appears strongly linked to heat and humidity is of great concern going forward, given that a climate change-induced increase in temperature is projected for the region. Median temperatures in May have risen 18 degrees Fahrenheit over the past decade. If the steppes of Kazakhstan experience another, similar event—and all the saiga antelope are within that weather envelope—it could be total extinction within a week.
There’s evidence that such unusual weather patterns are having matching impacts on other animal populations, such as musk ox and reindeer. This could soon be a global phenomenon.
Lack of action is the death knell
Just as surely as we are losing saiga antelope, we’re in danger of there being no Adelie penguins, American pikas, monarch butterflies, narwhals or golden toads, which were last seen in 1989. All of these animals are recent victims of a warming Earth and climate change—and our failure to address this critical, planet-wide issue.
It’s clear that if you and I demand that our leaders take action to abate climate change, we may be able to stave off more mass die-offs and the bizarre events that can lead to extinctions for a variety of animals. For, as the saiga antelope deaths demonstrate, even seemingly innocuous, small changes in the world’s temperature and humidity can have devastating and deadly effects.
Here’s to your adventures, in whatever corner of the world you find them,