Rising Temperatures: All Creatures Great and Small. By Julie Peller, Ph.D.

Green Junction

One major consequence of climate change is the loss of biodiversity. Other reasons for the decline in natural populations include changes in land use, pollution, and exploitation of natural resources. According to a 2024 report by the World Wildlife Fund (WWF), the average decline of wildlife populations between 1970 and 2020 for 5,495 vertebrate species was 73%. Simultaneously, the warming global climate has created conditions for increases in the populations of certain insects and invasive species. These include some mosquitoes, beetles, and ticks.

Many insect species have responded to rising temperatures by moving northward or to higher elevation, as well as to urban areas. Ticks are now present in more areas, and their populations have been rising. The range of deer ticks, also known as blacklegged ticks, has expanded, leading to more cases of the diseases they spread, namely Lyme disease and Anaplasmosis, a bacterial disease first recognized in Minnesota in the early 1990s. Over the past three decades, incidences of Lyme disease have doubled,d and deer ticks continue to move north.

Dr. Lars Eisen, at the National Center for Emerging and Zoonotic Infectious Diseases, wrote a paper earlier this year titled “Why are the ticks winning, and what can we do about it?” The loss of some species that serve as predators for ticks is one reason for the increase in ticks. Animals that feed on ticks include opossums, wild birds, some lizards, and foxes. Meanwhile, the population of deer, on which older ticks feed, has risen because they have fewer natural predators.

The CDC’s suggestions for limiting exposure to ticks include learning where ticks are present, avoiding areas with high tick populations (grassy, wooded areas), and applying insect repellents that are deemed safe and effective. After outdoor excursions, it is also important to check for ticks on your body, clothing, and pets.

Julie Peller, Ph.D., is an environmental chemist (Professor of Chemistry at Valparaiso University). She has been writing a weekly column, The Green Junction, for the past years and is helping to move the call of Laudato Si to action. Her research interests include advanced oxidation in aqueous solutions, water quality analyses, emerging contaminants, air quality analyses, challenges along the Lake Michigan shoreline (including Cladophora, water, and sediment contaminants), and student and citizen participation in environmental work.