In recent years much has been written about Anthropogenic Global Warming AGW. President Obama stated that Anthropogenic Global Warming is a major threat to the nation and he will be promoting a climate change treaty to be signed in Paris by the end of 2015. He wrote

“Climate change is an urgent and growing threat to our national security, contributing to increased natural disasters, refugee flows, and conflicts over basic resources like food and water. The present day effects of climate change are being felt from the Arctic to the Midwest. Increased sea levels and storm surges threaten coastal regions, infrastructure, and property. In turn, the global economy suffers, compounding the growing costs of preparing and restoring infrastructure.”

If a treaty is agreed upon, it likely will severely restrict the use of fossil fuels to generate energy in the future.  But Obama is not the first U.S President to make comments on climate change. A former President wrote:

The change which has taken place in our climate is one of those facts which all men of years are sensible of and yet none can prove by regular evidence. They can only appeal to each other’s general observation for the fact. I remember that when I was a small boy, say sixty years ago, snows were frequent and deep in every winter, to my knee very often, to my waist sometimes, and that they covered the earth long. And I remember while yet young to have heard from very old men that in their youth the winters had been still colder, with deeper and longer snows. In the year 72, thirty-seven years ago, we had a snow two feet deep in parts of this state, and three feet in the counties next below the mountains.

The prose is somewhat old as this was written by President Thomas Jefferson in 1809, who was very interested in meteorology. The comment was after the Revolution when one can see pictures of Washington crossing the Delaware with ice in December and a bitterly cold winter at Valley Forge. Temperatures were historically colder at his time than the current day and have been warming for the past two centuries. Comments similar to these can also be written from that time to the current time.

The particular problem of climatic change is really quite an old and familiar one. Each generation seems to espouse some theory as to the changing climate. Within my lifetime, climate change has been blamed on nuclear tests, atmospheric aerosol pollution, and now carbon dioxide from burning of fossil fuels.

Actually, from the standpoint of meteorology, the weather is always changing, never static. The atmosphere is a restless medium undergoing all sorts of transitory variations-not only on an hourly or daily scale, but also on weekly, monthly, yearly, decadal, and greater scales up to the ice ages. Meteorologists are engaged in modestly attempting to detect and predict some of these variations and work with periods of the order of a week to a month. We would indeed be surprised if there were no major changes taking place even of the order of a year, two years, or even a century or longer.   So the climate is always changing.