The letter by Malcolm J. Sherman ("Models don't show climate emergency," July 16) claims that global temperatures have not risen since 1998, and that this is not predicted by models of climate change that have raised the alarm about global warming.
There is no real doubt the planet has gotten warmer. Air temperature data fluctuate widely from year to year, and it is possible to identify many short intervals when the temperature is lower at the end than at the beginning. What is important is that the mean over the last 100 years has increased.
The main reason for this is the increase in atmospheric carbon dioxide, which has gone from about 295 parts per million in 1900 to more than 398 parts per million today. This increase is due to the release of fossil carbon by combustion of fossil fuel, as shown by the lowered ratio of carbon-14 to carbon-12 in the air. Old carbon has lost C-14 due to radioactive decay.
Mr. Sherman's argument, though based on a misinterpretation of the facts, would preserve the status quo rather than deal with the emerging population and environmental crisis that threatens our civilization.
Harry Roy
Troy