For the past three decades, monarch butterflies have been dwindling.
The iconic bugs face a number of threats in North America, from weed killers to climate change, but it hasn’t been clear which one has been the most damaging. A new study, however, indicates that the butterflies are especially sensitive to weather conditions in their spring and summer breeding grounds.
Scientists analyzed data from more than 18,000 monarch counts from across the United States, Mexico, and Canada spanning 25 years. They found that over the past 15 years, climate had an influence on the eastern monarch population that was nearly seven times that of other variables such as herbicide use.
At the time of this writing, at least 120 people have been confirmed dead because of severe flooding in Western Europe.
It is tragically likely that, when this story is over, the number will be significantly higher. A German weather service (DWD) spokesman told CNN that in some areas there has not been this much rainfall in 100 years.
These extreme weather events are inextricably linked to climate change, politicians and experts have noted.
But there is another culprit, one above, that is also affecting the weather: a “wobble” in the orbit of the Moon. Indeed, only days before the flooding, a study in the journal Nature Climate Change by scientists from NASA and the University of Hawaii warned that the Earth may experience record flooding in the mid-2030s because of changes in the Moon’s orbit.
Of all the things attributable to climate change, the rotational poles moving differently is definitely one of the weirder ones. But a new study shows that’s exactly what’s happening. It builds on previous findings to show that disappearing ice is playing a major role, and shows that groundwater depletion is responsible for contributing to wobbles as well.
The findings, published last month in Geophysical Research Letters, uses satellites that track gravity to track what researchers call “polar drift.” While we think of gravity as a constant, it’s actually a moving target based on the shape of the planet. While earthquakes and other geophysical activities can certainly play a role by pushing land around, it’s water that is responsible for the biggest shifts. The satellites used for the study, known as GRACE and GRACE-FO, were calibrated to measure Earth’s shifting mass