by Daniel Brouse and Sidd Mukherjee
A dog panting helps with thermal regulation primarily through evaporative cooling. Here’s how it works:
- Evaporative Cooling: When a dog pants, it increases the airflow over the moist surfaces of its tongue and the lining of its upper respiratory tract. This enhances evaporation of moisture from these surfaces, which cools the blood vessels lying just beneath. As the blood circulates through the body, it helps to lower the overall body temperature.
- Heat Dissipation: Panting allows the dog to expel heat from its body. Dogs do not sweat through their skin as humans do, except for a minimal amount through their paw pads, so panting is their primary method of cooling down.
As for the wet-bulb temperature, it does impact a dog’s ability to cool itself through panting:
- Wet-Bulb Temperature: This measurement takes into account both temperature and humidity. High wet-bulb temperatures indicate high humidity, which reduces the efficiency of evaporative cooling. When the humidity is high, the air already holds a lot of moisture, making it harder for the moisture on the dog’s tongue and respiratory tract to evaporate. This reduces the effectiveness of panting as a cooling mechanism.
In summary, dog panting helps with thermal regulation by facilitating evaporative cooling. However, its effectiveness can be impacted by the wet-bulb temperature, particularly in high-humidity conditions where evaporative cooling is less efficient.
Why is the wet-bulb temperature becoming so important?
The greatest short term climate change risk to human health is deadly humid heat (wet-bulb temperature) caused by a warmer average temperature enabling the air to hold more moisture. Increased moisture leads to higher humidity.
The Water Vapor Feedback Problem
Water vapor is a powerful greenhouse gas. Since the 1970s, its rise likely increased global heating by an amount comparable to that from rising carbon dioxide. We are now seeing the consequences. In the current climate, for average all-sky conditions, water vapour is estimated to account for 50% of the total greenhouse effect, carbon dioxide 19%, ozone 4% and other gases 3%. Clouds make up about a quarter of the greenhouse effect.
The main greenhouse gases — carbon dioxide, methane, nitrous oxide and ozone — don’t condense and precipitate. Water vapor does, which means its lifetime in the atmosphere is much shorter, by orders of magnitude, compared to other greenhouse gases. On average, water vapor only lasts nine days. The increased intensity of precipitation often results in violent rain.
Sidd said, “The biggest feedback loop is water vapor. Humans put CO2 in the air. CO2 is a greenhouse gas, so the earth gets warmer. Warmer air can hold more water vapor soaking up more water vapor from the oceans. Water vapor is a greenhouse gas, so it gets even warmer… rinse (sorry!) and repeat. Another interesting thing is that the precipitation (rain, snow, sleet) intensity is increasing.”
Due to climate change humans will experience greater loss and damage to life and quality of life from air pollution, decreasing supply of potable water, extreme weather events, and disease. The greatest short term climate change risk to human health is deadly humid heat (wet-bulb temperature).
* Our climate model uses chaos theory in an attempt to adequately account for humans and forecasts a global average temperature increase of 9 degrees Celsius above pre-industrial levels. Everybody has the responsibility not to pollute. There are plenty of things you can do to help save the planet. Stop using fossil fuels. Consume less. Love more. Here is a list of additional actions you can take.
Climate Change and Health
What you can do today. How to save the planet.
The Human Induced Climate Change Experiment