Eleanor Hildebrandt | November 26, 2021
More monarch butterflies are migrating to the western U.S. as wintery weather appears in other parts of the country, a sign of habitat loss slowing.
In the past 20 years there has been a more than 80 percent drop in the amount of monarchs that migrate, according to the National Wildlife Federation in 2018. Others speculate the numbers have fallen more than 99 percent. Over a million butterflies used to make the trip in the late 1900s, but now only thousands make the trek. The numbers are picking up significantly in 2021, NPR reported, with more than 100,000 monarchs hitting California already.
The endangerment of monarchs has occurred over the past few years. National Geographic charges humans and man-made climate change as the reason why this is happening. There are projections for monarch numbers to drop drastically in the next 20 years, leading to definite extinction.
Increases in carbon dioxide levels impacts the growth of milkweed plants—monarchs only food source as caterpillars. The plants are becoming too toxic for the caterpillars to consume, so the insects die off before metamorphosis. Planting milkweed is a way to help save monarch butterflies from extinction alongside decreasing carbon dioxide emissions.
Another reason for this is monarchs are being shaped differently because of climate change. The wing size of the butterflies is changing. The mutation helps monarchs travel longer, but the lack of food could kill off the butterflies before the increased wingspan could help or harm the species.
The increase in monarchs migrating this year is a good sign, but it doesn’t take monarchs off the endangered species list yet.