Monarch Butterflies Now an Endangered Species Due to Climate Change, Actions Human Have Taken, Experts Say

Monarch butterflies are officially an endangered species, international conservationists announced. Several factors have contributed to the lessening population, including humans, weather and climate change. 

“What's happening to monarchs is like a death by a thousand cuts,” said Karen Oberhauser, director of the University of Wisconsin-Madison Arboretum. 

"Farmers started using crops that they could spray herbicides on without killing the crops, so genetically modified crops, and they’re actually used to be a lot of monarchs' host plant, milkweed, in corn and soybean fields,” she continued. “But as farmers changed their weed control methods, that milkweed disappeared, and because much of the breeding range of monarchs is used for farming, a lot of that habitat is just gone now, those corn and soybean fields that used to have milkweed growing in them."

Climate change and weather conditions are also to blame. 

"As we're seeing with all of the extreme weather events going on this year, there's also a change in the climate, and we know that…monarch numbers are really tied to variation in year-to-year weather, and that the conditions that are best for monarchs are becoming more rare,” she said. “So, the hot and dry conditions are not good for them.”

Extremely cold temperatures can also negatively affect insects. 

"If monarchs get wet from the snow, and then if the temperature drops, they're much more susceptible to freezing,” she said. “So the last big die-off for monarchs was in the year 2016 when there was a big storm in Mexico that killed what some people estimate between 60 and 70% of the population."

More than 41,000 species are currently at risk of going extinct, according to the International Union for Conservation of Nature. And scientists say humans are mainly to blame. 

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