Tick season comes around every year, but no two tick seasons are always the same. Many factors play into how ticks survive and thrive in certain areas. One of the biggest factors is climate. The environment in which ticks live needs to be perfect for them to breed and survive throughout the year – meaning ticks and climate change have more to do with one another than you might have thought.
Depending on climate conditions, one of two things can happen: tick populations can die down, or they can breed and spread out of control. Tick populations have rarely remained steady because of significant changes to the environment in recent decades. Climate change affects species across the globe, and ticks are just one of the many species whose trajectory can be altered by changing climates.
What are environmental factors for ticks?
The survival of ticks and climate change go hand in hand. This is because many environmental factors play a role in tick populations. Let’s take a look at some of those factors now.
Temperature
The life cycle of a tick is highly influenced by fluctuating temperatures. When typically colder areas heat up earlier than usual or stay hotter for longer, it gives more ticks a chance to mature through their life cycle. This leads to larger tick populations and more prolonged tick activity. Temperature also plays a role in how long a period ticks have to seek out hosts, such as humans, to feed upon.
Humidity
Higher temperatures alongside high humidity levels make for prime conditions for tick populations to survive and thrive. Ticks in areas with both high temperatures and high humidity levels can reproduce more effectively and live longer throughout the year.
Precipitation
The amount of precipitation an area gets will significantly affect tick populations. When there is more precipitation, ticks are less active than they would be if the area were drier. Some research has suggested that more precipitation can lead to a tick endemic, but more studies are needed to confirm this.
Land use priorities
When more wooded areas become paved over, tick populations must migrate to areas where they can feed and survive. As these changes take place, ticks can spread out of pure necessity to areas of the country where they aren’t typically found. Ticks left behind may end up reproducing and living in more suburban areas, giving them easier access to human hosts.
Forest fragmentation
Forest fragmentation is the destruction of specific forested areas that interrupts the ecosystem. When this happens, it can increase the chances for deer and other primary tick hosts to grow in certain areas as they are pushed into smaller areas of suitable habitats after deforestation. The main effects that drive higher tick populations are increased animal hosts, such as deer and white-footed mice, and increased human exposure.
Extreme weather events
Flooding, forest fires, and other extreme weather events can decrease tick populations by making conditions less than survivable. These events can also reduce the number of hosts ticks have access to, causing mortality rates to rise.
When all the above factors are just right, tick populations can soar beyond what is expected, making it much easier for them to seek out human hosts more often. If they are bacteria carriers, they can also spread diseases such as Lyme to more hosts.
What are the effects of climate change on ticks and tick-borne diseases?
Climate change has led to an increase in global temperatures. This increase can cause devastating effects on the natural world, such as wildfires, soaring heat waves, and the melting of polar ice caps that cause sea levels to rise. To say that climate change is detrimental to all species on the planet would be an understatement.
When looking at ticks and climate change specifically, these changes have made it much easier for tick populations to survive longer. Many wooded areas that usually see longer winters may be experiencing higher (often unseasonably warm) temperatures. In wooded areas where ticks live, the time periods available for feeding are getting longer and longer.
When considering climate change and Lyme disease, it’s important to note that larger tick populations encouraged by changing climate conditions can lead to further spread of the disease. When there are more ticks, and the chances of encountering them are higher, humans can be more at risk of exposure to tick-borne diseases. These diseases can also spread more easily from ticks to animal populations.
What was the link between climate change and the spread of Lyme disease?
Ticks spread Lyme disease when they latch onto a host, human or animal, for 24–36 hours. During that time, they can transmit the Borrelia burgdorferi bacteria from their blood into the blood of their host. If tick populations have a more extended period to feed due to climate change while also reproducing in higher amounts, the spread of Lyme disease is much more concerning. The higher the tick population and the more access they have to humans or other hosts such as deer, the further and faster Lyme disease can spread.
Addressing climate change can help keep tick populations at bay, but the difference will be insignificant unless problems are addressed on a large scale. The best thing you can do personally is learn about tick populations in your area, protect yourself when you’re out in the woods, and always ensure that if you find a tick on you, you remove it promptly and send it in for testing.
