Contrary to a letter Tuesday ("Scientists cry wolf about climate change"), there is no “drop dead” date for effects of climate change. However, scientists with the Intergovernmental Panel on Climate Change (IPCC) insist “scientific evidence for warming of the climate system is unequivocal.”

And 97 percent of climate scientists agree that climate warming trends over the past century are extremely likely due to human activities, and most of the leading scientific organizations worldwide have issued public statements endorsing this position.

The IPCC says, “The current warming trend is of particular significance because most of it is extremely likely (greater than 95 percent probability) to be the result of human activity since the mid-20th century and proceeding at a rate that is unprecedented over decades to millennia.”

Evidence of these changes include rising global temperatures, warming oceans, shrinking ice sheets, retreating glaciers, decreased snow cover, rising sea levels, declining Arctic sea ice, extreme weather events and ocean acidification.

This is a complicated subject, and I don’t pretend to understand all the data. But there are many sources of information online, many in easy-to-read language. My statements are from this website: I try to make my judgments as much as possible from the findings of scientists who spend their lives studying their subjects. Unfortunately, the Trump administration’s ignorance of, and refusal to even consider, the findings of science as a whole is disgraceful at best and extremely dangerous to all of us at worst.