By Don Vaughan

The United Kingdom does not get hot. Even in the summer, the temperatures there tend to hover in the balmy 70s. As a result, very few businesses and homes have air conditioning. Staying warm has always been far more challenging than staying cool.

Until July 2022, that is. That was when climate change hit home. Over an especially challenging few days, temperatures in London and elsewhere soared to 104 F., sending scores of people to the hospital—many of whom also lacked air conditioning—for heat-related ailments. A second serious heat wave struck in August. England wasn’t alone; much of continental Europe was similarly affected by excessive summer heat.

The dangerously high temperatures recorded in Great Britain and Europe are just the latest indication of how climate change is wreaking environmental havoc around the world. In the United States, the impact is equally worrisome. Western states are experiencing devastating wildfires and an ongoing drought that threatens the water supply for millions. In the Midwest and East Coast, severe tornadoes and 100-year storms have become routine, devastating entire communities. This is our new normal, climate experts warn, and it’s likely to get worse.

The effects of climate change on people make the news almost every night. Less reported, but equally important, are its effects on pets, livestock and wildlife, and the veterinarians who care for them.

“Human health authorities have said, very emphatically, climate change is the number one public health threat of the 21^st century,” says Colleen Duncan, DVM, PhD, DACVP, DACVPM, associate professor in the Department of Microbiology, Immunology and Pathology at the Colorado State University College of Veterinary Medicine and Biomedical Sciences in Fort Collins. “However, these impacts are not restricted to people. Veterinary associations around the world are similarly declaring climate change poses a monumental threat to animal health.”

Climate change is a global issue, but the specific health effects on pets, livestock, and wildlife vary widely by geographic region. Dr. Duncan details a variety of pathways in which animals are commonly affected. They include:

• Extreme weather events, such as wildfires, torrential rainstorms that result in flooding, tornadoes, and extreme blizzards. All of these can result in illness or injury to animals.
• Air quality. “In some cases, air quality is tied to extreme events like wildfires, but also things like ground-level ozone, which is produced on warm, sunny days,” Duncan explains. “We’re seeing a lot more air pollution tied to climate change.”
• A broader geographic spread of vector-borne diseases, such as Rocky Mountain spotted fever and Lyme disease. Consistently warmer weather is helping some ticks and other vectors expand their range. “The vector-borne disease signal related to climate change is undeniable,” says Janet Foley, DVM, PhD, professor, University of California, Davis, School of Veterinary Medicine. “Rocky Mountain spotted fever, which is caused by a tick that loves hot weather, is moving north. This is a disease that can be fatal in people and dogs. At the same time, Lyme disease is transmitted by a tick that prefers it cool and moist. And with climate change, we don’t even know where the risk of Lyme disease is moving because that kind of ecology work takes years.”
• Generally hotter weather. As noted, an increase in temperatures has become a signature symptom of climate change, and it can adversely affect animals in a variety of ways. For example, hotter weather can influence the amount production animals are able to produce. On the home front, it can result in sunburned skin and burned paws from walking dogs on sunbaked roads or sidewalks.

In Great Britain, pet owners have been advised to review their animals’ housing to prevent them from getting heatstroke during the warmer months. A study at Nottingham Trent University looked at five years’ worth of data from a network of veterinarians and found while dogs accounted for most heatstroke cases, cats, guinea pigs, rabbits, and ferrets were also affected. Among dogs, brachycephalic breeds, such as French bulldogs, were particularly at risk, the study revealed.¹

• Availability of clean drinking water. Wildfires throw a lot of pollution into the air that will eventually fall to the ground, contaminating drinking water, Duncan says. The issue may be made worse by the use of air-dropped fire retardants, which can also get into the local water supply. Wildfires can also contaminate pastureland where animals graze, adds Robert Poppenga, DVM, PhD, DABVT, professor, California Animal Health and Food Safety Lab, University of California, Davis. “It’s not only the forests that are burned, but many times it’s also entire towns,” he explains. “That’s a concern and a lot more research needs to be done regarding its effects.”
• Welfare. “In human medicine, the impact of climate change on mental health has become an active area of research,” Duncan says. “We can’t ask animals about their mental health, but the stress associated with any of these climate-related environmental changes is a huge animal welfare issue.”

Some animal health issues associated with climate change can be mitigated with common sense, such as reminding clients to walk their dogs on grass instead of hot pavement, ensuring they are protected from sunburn, and providing shelter and water when the animal is outdoors. Alas, there is one aspect of climate change that cannot be prevented: more frequent and severe natural disasters.

Double catastrophes

Depending on the type of disaster, the impact on animal health can be catastrophic. Wildfires may result in serious burns and respiratory issues. Hurricanes and tornadoes may result in blunt-force trauma from flying debris or collapsed buildings. Flooding may expose animals to toxic substances. Blizzards may cause frostbite, hypothermia, and more. In some cases, unexpected health effects may develop long after the initial event. For example, a recent study by researchers at the University of California, Davis, Veterinary Medical Teaching Hospital, published in Frontiers of Veterinary Science, found cats experienced burns and smoke inhalation in urban California wildfires were at risk of forming deadly blood clots.²

Hurricane Katrina, which devastated New Orleans in 2005, led to significant changes in how animals are managed during a natural disaster. “A lot of people didn’t want to leave their homes during Hurricane Katrina because they had pets [and couldn’t take them to shelters],” Duncan explains. This led to the creation of the PETS Act, which ensures state and local emergency preparedness operational plans address the needs of individuals with household pets and service animals following a major disaster or emergency.

Duncan encourages all animal owners, including pet owners, ranchers and farmers, to have an emergency management plan in place specific to the welfare of their animals during and after a disaster.

Another aspect of climate change sometimes forgotten by animal owners is its effects on surface water quality. Dr. Poppenga is a veterinary diagnostician who, among other things, studies algae blooms. Climate change, he says, has driven an increase in the occurrence of such events, which can put dogs at risk because some forms of algae, particularly blue-green algae, produce toxins that can be deadly if ingested. In June, several dogs were sickened, and some died, after ingesting blue-green algae while swimming in Jordan Lake in Chatham County, North Carolina.

“The problem is definitely growing as a result of environmental factors,” Poppenga says. “When there is a lack of water, there can be less mixing in a lake or stream, as well as a concentration of nutrients in impacted waters. All of these things lead to the algae blooms most of the world is seeing right now. The toxins that are produced can damage the liver, and there are neurotoxins that affect the nervous system.”

In the thick of it all are community veterinarians, who act as a frontline defense to the growing challenges of climate change. Their role has evolved in recent years as the issue of climate change has gone from debate to accepted fact, though there is still the occasional climate change denier to be dealt with. It’s in this space that many veterinarians have added climate change education to their list of client responsibilities.

“We are scientists, we are medical experts, and in some areas, we may be more accessible to people than their physician,” explains Kate Meurs, DVM, PhD, DACVIM, Dean, North Carolina State University College of Veterinary Medicine in Raleigh. “I would encourage veterinarians to get out into their community and talk about the environment that we live in. Talk to your local 4-H Club. Visit schools. Visit the Rotary Club. Provide education on how to care for animals in higher heat, or rescue animals when they are displaced.”

Dr. Meurs encourages veterinarians to broach issues related to climate change during a general discussion of a patient’s health. “When talking to someone about making sure their horse has plenty of water or enough shade, you can bring into the conversation how the climate is changing and its effects on animal health,” she says. “I think you can start with conversations about how we know more now than we used to, and then bring into that how climate is a bit different now so we might need to adjust.”

Don Vaughan is an award-winning writer who frequently writes about veterinary-related topics.

References

1. Risk Factors for Severe and Fatal Heat-Related Illness in UK Dogs – A VetCompass Study by Emily J. Hall, et al. Vet. Sci. 2022, 9(5), 231; https://doi.org/10.3390/vetsci9050231
2. Platelet Priming and Activation in Naturally Occurring Thermal Burn Injuries and Wildfire Smoke Exposure is Associated with Intracardiac Thrombosis and Spontaneous Echocardiographic Contrast in Feline Survivors, by Avalene W.K. Tan, et all. Front. Vet. Sci. 2022; July 14.