Ask any hunter, angler, birder, or gardener and they will tell you that the environment is changing.
Americans have a passion for the outdoors. Unfortunately, across the United States and around the world, climate change poses an increasingly dire threat to wildlife, communities, and public health. Changes to our climate are destroying critical wildlife habitat, causing species’ ranges to shift, decreasing available food and water for wildlife, changing the chemistry of the ocean, and increasing the rate of species’ extinction. Of huge concern are warmer winters, which serve as a welcome mat for pests like ticks to expand their range.
Ticks, which are not insects but arachnids (like spiders), are pests that outdoor enthusiasts have learned to avoid. Climate change is influencing ticks, the survival of their hosts (such as deer and moose), and the bacterium that cause the diseases they carry, such as Lyme disease. The ways in which temperature, humidity, and precipitation are impacting the spread of tick-borne illnesses is complex, and scientists are continuing to learn more, but some general trends can be seen.
- The geographic areas in which ticks can survive and thrive are expanding as a result of climate change.
- Milder winters, which are expected to become frequent as a result of climate change, also result in more ticks surviving the cold season. This can lead to population booms, which in turn can increase the risk of tick-borne illness.
Types of Ticks and the Diseases They Transmit
Only a few species of ticks bite and transmit disease to people. Of these, different species transmit different diseases.
- The American dog tick, also called the wood tick, transmits Tularemia and Rocky Mountain spotted fever. Highest risk of being bitten by this tick is spring and summer.
- The blacklegged tick transmits Lyme disease, anaplasmosis, ehrlichiosis (Ehrlichia muris eauclairensis), babesiosis, Borrelia miyamotoi, and Powassan disease. Highest risk of being bitten by this tick spring, summer, fall, and winter when temperatures rise above freezing.
- The brown dog tick transmits Rocky Mountain spotted fever, though this species bites dogs more often than humans.
- The gulf coast tick transmits a form of Rocky Mountain spotted fever called Rickettsia parkeri rickettsiosis, though this species doesn’t bite people as often.
- The lone star tick transmits Ehrlichia chaffeensis and Ehrlichia ewingii (which cause human ehrlichiosis), Heartland virus, tularemia, and STARI. This tick species is fairly aggressive species.
- The Rocky Mountain wood tick transmits Rocky Mountain spotted fever, Colorado tick fever, and tularemia.
- The Western blacklegged tick transmits Anaplasmosis and Lyme disease.
Impacts to Outdoor Recreation
Nearly half of the people in the United States spend time engaged in outdoor recreation, including canoeing, fishing, hiking, camping, hunting, kayaking, swimming, bird and wildlife watching and more. Today, this outdoor economy is worth $887 billion in the U.S. economy and it supports 7.6 million jobs. But a changing climate with rising temperatures and more frequent extreme weather events and the rise of pests like ticks are impacting these activities.
Fear of ticks and risk of disease can prevent people from fully enjoying the outdoors. People need to be able to enjoy nature, whether it’s on trails or in their own gardens.
Impacts on Wildlife
Winter ticks are a common parasite for large game in North America. During the fall, winter tick larvae transfer from vegetation to large mammals such as moose when they brush by them. A moose can be parasitized by thousands of ticks at a time, as they stay on their host throughout their winter lifecycle.
Climate change is helping winter tick populations grow. Tick activity increases as temperatures increase, meaning they have more time to find a host during a warmer fall. A late onset of winter also means higher tick populations, since snow and cold normally help kill some of them off. Earlier springs with less snow on the ground also help winter tick populations grow.
Winter ticks can infect moose, elk, caribou, white-tailed deer, and mule deer, but moose are the most susceptible to severe infestation. Moose are in jeopardy across the U.S., from New Hampshire, Vermont, and Maine to Minnesota, Michigan, and even Wyoming. The rising winter tick populations in Maine, New Hampshire, and Vermont have contributed to increased mortality, reduced productivity, and population decline. As the moose population drops, the recreational activities and associated revenue surrounding the species is sure to follow.
Wildlife to the Rescue
Some wildlife are actually unsung heroes when it comes to preventing the spread of tick-borne diseases. The opossum, the only marsupial in the United States, is one example of this. Opossums are truly remarkable tick killing machines—one opossum can kill as many as 4,000 ticks in a week. Because possums are so good at grooming and killing ticks, they help keep tick populations under control and reduce the risk of people being bit.
Some species, such as the Western fence lizard, have the ability to neutralize Lyme disease when infected ticks bite them. Lyme disease is now the most common vector-borne disease in the United States, making it a big problem for outdoor lovers. The C.D.C. estimates that about 300,000 Americans get Lyme disease each year, but only about 35,000 diagnoses are reported.
How to Prevent Tick Bites
Limit your exposure to ticks with these tips from the Centers for Disease Control and Prevention:
- Stay on the trail! Avoiding woody and brushy areas, and areas with high grass and leaf litter, will reduce your risk of being bitten.
- Cover exposed skin with long-sleeved shirts and long pants.
- Use repellent that contains 20 percent or more DEET, picaridin, or IR3535 on exposed skin for protection that lasts several hours
- Treat your clothing with 0.5 percent permethrin, this protection will repel ticks and will continue to offer protection after several washings. Many brands of outdoor gear will treat their clothing.
- Bathe, shower, or check for ticks when you are done with your outdoor adventures.
- You can also tumble dry clothes in a dryer on high heat for 10 minutes to kill ticks on dry clothing after you come indoors.
Take Action
Americans have a responsibility to defend their outdoor heritage from the threat of climate change. There are ways to protect ourselves from the pests that climate change is helping to proliferate. Ticks should not stop you from enjoying activities like camping, hiking, and playing outdoors—but make sure to take steps to prevent tick bites. Also, we must take action as a nation to combat the root of the problem—carbon pollution. It is critical for Congress to take action and enact federal climate policy. The following examples highlight four ways in which our government can take climate action.
The power sector is second-largest source of climate pollution in the U.S. To minimize climate change risks such as the spread of tick-borne disease, the federal government should take action to reduce these harmful emissions. The Clean Power Plan, currently being repealed by the Trump Administration, would have reduced power plant climate pollution by more than thirty percent if implemented. The plan is an example of the type of proactive, far-reaching policy we need. Further, our leaders at the national and state levels should adopt policies to ensure we have clean, wildlife responsible renewable energy sources, such as offshore wind and rooftop solar power.
Methane gas that leaks and is intentionally released from oil and gas facilities in the U.S. is a significant source of climate pollution. This climate-altering gas is a super pollutant, with 80 times the impact of carbon dioxide in the short term. This gas should be captured through common sense standards, not released freely to the air. The Environmental Protection Agency and Bureau of Land Management have each developed cost-effective rules for minimizing methane emissions, though both rules are under threat due to rollback actions from the Trump Administration.
The transportation sector is now the top source of harmful climate pollution in the U.S. Automakers had been working to continually improve fuel efficiency and reduce carbon pollution in their fleets over time, as required by federal rules. Recent actions by the Trump Administration to roll back these clean car standards pose a serious threat to climate progress. This country needs stronger climate rules, not weaker ones.
One of the most cost-effective, far reaching, and quickest avenues for reducing climate pollution is a federal price on carbon. A federal price on carbon could take the form of either a cap-and-trade program or a carbon tax program, or some combination of the two. By making polluters pay for what they emit, they receive a strong market signal to cut pollution. Such policies could dramatically reduce carbon emissions while generating funding for national priorities, such as protecting vulnerable people and wildlife from unavoidable climate impacts or developing wildlife-friendly renewable energy.
Federal action on climate is necessary, not only for America’s wildlife, fish, and birds, but for the millions of sportsmen, wildlife watchers, and nature lovers who cherish America’s outdoor heritage. The health of wildlife and outdoor enthusiasts can’t wait for climate action.
Read more in Climate Change Bites!: The impacts of ticks on wildlife, public health, and outdoor recreation (PDF).
