What is happening to the weather?
Forty-five people were killed last week when a devastating storm system plowed a path of destruction across the Southeast. Witnesses to tornado clusters in Alabama and North Carolina said it was like nothing they had ever seen before. North Carolina, which averages 19 tornados per year, saw what might have been 90 tornados in just a few days. At one time, it may have been called the storm of the century, but that term has lost its meaning. Storms of the century now seem to barrel across the country every few weeks. A CNN meteorologist described the latest storm as epic.
A blizzard paralyzes New York City. Washington, D.C. suffers through a “snowpocalypse” only to be buried again a few weeks later by what the media then termed “snowmaggedon.” Florida freezes, rain pours down on Southern California and the north digs out of snow so frequently that people stopped trying to find clever names for it. When the snow melted, tornados destroyed an Iowa town followed by other tornados that destroyed lives across the south. What is happening to the weather? Are storm warnings to become a permanent fixture of the planet Earth?
The theories for why the weather seems so extreme run the gamut from simple to the lunatic fringe. Some weather observers say there is nothing unusual about heavy snow in the winter in the northeast or tornados in Iowa; and if the weather appears to be worse than normal, it is merely because our instant access to information on the web makes it seem worse. On the other end of the spectrum are those who believe a radio antenna in Alaska is causing not only extreme weather events, but also earthquakes and tsunamis. The antenna actually exists, by the way, as does the government project, the High Frequency Active Auroral Research Program, also known as HAARP, an unclassified project studying the ionosphere for radio communications and surveillance purposes.
The truth, as usual, likely lies somewhere in between. The problem is that no one really knows with certainty—except for the fact that it is not likely to be the result of an antenna in Alaska. Is weather becoming more extreme? Yes and no, says the National Oceanic and Atmospheric Administration (NOAA), arguably the world’s foremost expert on weather and climate. It all depends upon where you are; and your perspective in time.
If anything can lay claim to the “butterfly effect,” a belief that something as minute as the flapping of a butterfly’s wings could create a chain of events that lead to much larger things, it is global weather. Faraway weather systems impact other systems that change others making for a stormy, hot, cold or beautiful day in the Tampa Bay area. Weather is dynamic and is in a constant state of flux — not only from day to day but also from century to century.
According to NOAA, there have been changes in global temperature extremes, including decreases in the number of unusually cold days nights and increases in the number of unusually warm days and nights. As part of that, growing seasons globally appear to be increasing. That said, however, NOAA has seen no significant trend in annualized global temperature extremes when looking over the years. However, it has noted a significant decrease in temperature extremes over the years. In other words, there have been no significant changes in extreme high temperature but there has been a noticeable decrease in how much the temperature may vary on any given day.
In some parts of the world, there is evidence of increasing droughts; in other parts of the world, including the United States, there is no evidence of that. There is, however, evidence of an increase in extreme precipitation events — and that has happened despite having no evidence that precipitation overall has increased globally. In fact, it may well have decreased.
By the same token, according to NOAA, extra-tropical cyclone activity appears to have increased in the northern hemisphere and decreased in the southern hemisphere. But that means little in Florida where the state hasn’t been hit by a major storm in six years, and even less to Australians battered by category 5 cyclone Yasi in February. To people in those areas, it would seem the opposite of what NOAA is saying is true.
Basically weather is relevant to when and where you are and averages mean nothing when it comes to extreme weather events on any specific day, just as the 36.8-year-old median age in the United States means little to the newborn or to the centenarian. Looking out over centuries, however, any given “storm of the century” may not be all that great in comparison to an event that may have happened centuries before. Or maybe it is. Last week’s storms weren’t without precendence as similar and worse systems hit the southeast in 2008 and 1974. Yet for non-meteorologists, good or bad weather is determined through the very narrow lens of our lifetimes and locations.
That lens is very narrow when considering Milankovitch cycles, which are widely believed to have an impact on climate, including Earth’s ice ages. Milankovitch cycles are a mathematical theory of variations in the earth’s tilt and distance from the sun. The sun, of course, is the primary force behind the planet’s climates. According to the theory, one full cycle occurs approximately every 26,000 years. But even that isn’t constant due to variations caused by the planet’s elliptical orbit that has a 21,000-year cycle along with variability of the earth’s axis which has a 41,000-year cycle. In other words, if you don’t like how the weather has been in your lifetime, just give it another 20 or 40 thousand years.
Unquestionably, the climate is changing just as it has since the dawn of time. Despite somehow becoming a political argument, there is also little question that the earth is warming. Satellite images of the earth’s poles and glaciers certainly confirm both are melting. The question, of course, is whether that change is impacted by man or is simply a part of a long cycle beyond our comprehension. Overall, the earth’s surface has warmed by an average of 0.74 degrees Celsius since the late 1800s. The rate of warming, however, has increased dramatically in the past 50 years. To add to the uncertainty, the rate of warming hasn’t been uniform across the planet. Florida has actually cooled slightly over the past century while Minnesota has become warmer. That said, according to NOAA, seven of the eight warmest years on record have occurred since 2001 and all of the 10 warmest years on record have occurred since 1995.
Local weather, however, isn’t so easily pigeonholed by global climatic changes. Next year’s weather on any given day in any given place may well be influenced by the flapping of a butterfly’s wings in a distant nation; but those wings haven’t flapped yet. Even so, short-term local weather has increasingly become a more exact science. Meteorologists from the National Weather Service, including the NWS office in Ruskin, have dramatically increased the accuracy of short-terms forecasts, no doubt working to incorporate the ever-changing global climate. The strong storm systems passing through the Tampa Bay area over the past several weeks were all predicted, up to and including the strong winds, hail and tornados. By and large, what errors the National Weather Service does make are made on the side of caution.
The weather is changing; it has always been changing. The global climate is an abstract and complex system that is felt by everyone on Earth through the costs of heating and cooling homes and, more importantly, the cost of food needed to survive. Yet there is little that any one individual can do about the global climate.
Speaking of extreme weather, the beginning of hurricane season is just over a month away. Tampa hasn’t been directly hit by a hurricane since 1921; but that doesn’t mean the area is overdue, nor does it mean it is immune. Last week, the North Carolina State University Department of Marine, Earth, and Atmospheric Sciences released a summary of their forecasts for the 2011 hurricane season. Their forecast included one to three hurricanes and three to five tropical cyclones developing in the Gulf of Mexico this year. They also forecast a 97 percent chance that at least one tropical cyclone will strike the Gulf Coast, including a 72 percent chance of a hurricane and a 45 percent chance of a major hurricane. In all, the forecast is predicting an active year with 13 to 16 named storms, exceeding the average of 9.6 named storms.
If the Tampa Bay area is hit by a hurricane this year, it will matter little whether or not the Milankovitch cycles played a role in it, nor will it matter that a hurricane hasn’t hit the area in 90 years. Whether this hurricane season, like the weather in general, is worse than any other will depend upon your location — one person’s catastrophe is another person’s near miss. If you don’t like it, just come back in 10,000 years to see if you like it better. In the absence of that, preparing for the worst and hoping for the best is something everyone can do about the weather today. Tomorrow, of course, it will be different.