Poison ivy is getting bigger and more potent, and the culprit is the 21st century's all-purpose scapegoat: climate change. The itchy, rash-inducing plant that has plagued hikers and gardeners since the beginning of time thrives in environments with high levels of CO2, the Journal reports, and with rates on the rise, the weed is growing like—well, a weed.
The three-headed scourge is also growing faster, with larger leaves and more powerful oil. A recent study exposing some plants to about the same level of CO2 as in the atmosphere in the 1950s and the some to the volume found today. After eight months, the "modern" poison ivy had larger leaves and higher levels of rash-creating oil.