COVID-19 cabin fever has led many Americans to venture outside moreーhitting the trails, playing at the park or enjoying the backyard. While scientists are confident that being outside reduces the risk of transmitting coronavirus, there are still some threats to be aware of when in the great outdoors. Among them are ticks and poison ivyーand both may be getting worse due to climate change.
Lyme disease, an illness whose incidence has doubled over the past two decades to 30,000 cases per year, is primarily transmitted by the blacklegged tick (also known as the deer tick). This sharp uptick is attributed to a number of factors, and one of them is our warming climate. In fact, the increasing incidence of Lyme disease is regarded by the EPA as an indicator of climate change. From ticks emerging earlier in the year to multiplying faster, warming temperatures can cause changes in tick behavior that affect our risk of catching Lyme disease.
A long-term study of the blacklegged tick in New York found that rising temperatures between January and May were associated with a peak in activity that was almost three weeks earlier for juvenile ticks (the ones most likely to transmit Lyme disease). As temperatures warm, ticks are able to develop faster and emerge earlier. This doesn’t necessarily mean that ticks will stick around longer, but faster development could increase the odds of them surviving to adulthood.
While you’re dodging ticks on your next venture outdoors, don’t forget about poison ivy! Higher levels of carbon dioxide in the atmosphere stimulate larger, more noxious growth of poison ivy (and potentially also its West Coast cousin, poison oak).
CO2 levels have risen rapidly in recent decades, which has already brought about a significant change in poison ivy plants. From around 1950 (300 ppm) to today (400 ppm), the increase in CO2 was associated with a leaf surface area more than doubling. The levels of toxic oil, known as urushiol, increased even more dramatically 一 by 173% in the same period.
While many species struggle to adapt, some (often troublesome ones like pests and weeds) find a way to thrive and overall biodiversity suffers. In order to maintain healthy ecosystems and healthy societies, we must work towards slowing change and stabilizing our climate by lowering greenhouse gas emissions.