Our Changing Climate: What Happened to Global Warming – It’s Cold Outside!
By Greg Czarnecki
At this time of year, when it's cold and snowy, it's easy to question whether climate change is real. After all, it's cold outside, and there's been record setting snow in parts of Europe and the U.S. It's important, though, to keep things in perspective. Just because you've got the furnace cranked up doesn't mean everyone does. In fact, parts of the Arctic have been experiencing record warmth.
According to NASA, 2010 tied with 2005 as the warmest year on record; this following 2000-2009, which was the warmest decade on record. This trend is in line with other temperature measures as well. The number of record high temperatures recorded annually has been steadily increasing for the past 60 years, according to the University Corporation for Atmospheric Research. During the 1960s the ratio of record highs to lows was 0.77:1. During the first decade of this century that ratio had risen to more than 2:1.
So don't fall into the trap of confusing weather—the conditions at a given time in a specific place—with the long-term trends of temperature, precipitation and other factors that determine climate. Think of weather as a single data point and climate as a database. While you can't draw any conclusions from a single piece of data, you can draw conclusions from trends in a database.
Do climate databases provide any insight into the unusually severe winter weather taking place in parts of Europe and the U.S.? It's important to recognize that we'll never be able to tie a specific weather event to climate change; earth's natural systems are far too complex and our understanding of them too rudimentary. Nonetheless, those databases can be used along with climate models to predict weather trends, and some of those analyses are pointing to more severe winters in parts of the northern hemisphere.
Here's why: The arctic has been heating twice as rapidly as the rest of the planet - a process called arctic amplification—because there's been a significant loss of seasonal pack ice as well as reductions in the area and thickness of multi-year ice. As the ice is lost, sunlight that was previously reflected back into space, a phenomenon known as the Albedo Effect, is now absorbed by open water. The water warms, which in turn heats the air above it. The warmer air leads to changes in barometric pressure and air currents, which then carry more polar air to the middle latitudes of North America and Europe than in the past.
According to a presentation by Dr. James Overland, of the NOAA/Pacific Marine Environmental Laboratory, at the Oslo Science Conference, "While the emerging impact of greenhouse gases is an important factor in the changing Arctic, what was not fully recognized until now is that a combination of an unusual warm period due to natural variability, loss of sea ice reflectivity, ocean heat storage and changing wind patterns working together has disrupted the memory and stability of the Arctic climate system, resulting in greater ice loss than earlier climate models predicted...Cold and snowy winters will be the rule, rather than the exception."
While it seems counterintuitive that global warming could lead to worse winters, time will tell if this theory holds true. As Dr. Overland points out, climate change is just one of the factors contributing to this effect, underscoring how complex our planet's climatic and physical processes are. This is a good example of why the phrase "climate change" is better than "global warming," which, although accurate, doesn't adequately describe the many ways that increasing greenhouse gases will affect our planet's natural systems and our daily lives.