Tuesday, January 10, 2012

Adirondack Climate Change: Rainfall Trends

A significant part of climate is precipitation, and fundamental to any discussion on the impact that global warming is having on a region’s climate would have to include possible changes to the rain and snowfall patterns. While unusually prolonged periods of precipitation can turn a backcountry camping trip into a nightmare, discourage golfers, boaters, and other outdoor enthusiasts, and frustrate anyone trying to put a new roof on his/her home, or a coat of stain on the deck, too much rainfall, especially concentrated over a short span of time, can wreak havoc with the environment.

As any student of ecology knows, the amount of water that an area receives is critical in influencing the forms of life that exist there. One of the least understood, and talked about aspects of climate change is what will happen to the fairly consistent supply of moisture that has helped maintain our lush forests and pristine waterways.

While a warmer atmosphere is capable of absorbing more water from the surfaces of the oceans and lakes, which may suggest a rainier planet, the issue of precipitation is far more complex. Certainly, the Adirondacks, along with the rest of the Northeast, have just experienced their wettest year on record, and widespread flooding was a major problem on more than one occasion.

A simple review of weather records reveals that along with enduring several record setting wet years over the past few decades (2006 & 1998), we have also experienced some exceptionally dry ones (2001). It is starting to appear that the moisture pendulum will swing in both directions with greater amplitude, unlike the temperature component of climate that is being permanently displaced to one side.

Another point of concern among some naturalists is the change that appears to be developing with regard to the intensity of our periods of rain. As a general rule, an atmosphere that is warmer has more energy to form larger and more powerful storm systems. As low pressure systems increase in their size and strength, the rain, or snow, they drop comes in more concentrated periods or downpours. This tends to lead to faster run-offs and flash flooding, which can impact the landscape in numerous ways.

Over the past few decades, there has been an increase in the number of avalanches and landslides that have scarred various hillsides across the Park. While there have always been cloud bursts that have resulted in the formation of a few slides on some of our steeper slopes, a comparison of how many mountains appeared a half century ago to what they look like today is evidence of the increase in the power of recent storms.

Aside from damage to the shoreline, flooding can adversely impact the abundance of aquatic organisms in our numerous waterways. The influx of large amounts of sediment into streams and rivers may not only cloud the water for a span of time, but the tons of fine granular material added to these aquatic systems can wreak havoc for considerable periods of time afterwards.

An increase in precipitation across the Park can create excessively wet soil conditions in many terrestrial settings that stress some components of the flora. It is like overwatering your household plants every few months. Some of them may continue to grow just fine while others may lose their vibrant green color, or fall victim to a plant fungus. Additionally, during years when moisture is limited, other types of stress develop among the plants and animals of that region. It has been noted that there has been widespread ecological damage done by the drought in Texas this past year.

Even though the temperature may not seem to warm very much, changes in the moisture cycles can be devastating to numerous plants and animals. In ecology, there are always other forms of life ready to replace any that have become weakened or have perished. Invasive species are probably better suited to deal with any wild fluctuations in the moisture cycle, as most forms of life that have evolved in warmer regions to our south seem to be as ill-adapted to contend with a more prominent monsoon/drought cycles than those native to this general region.

As noted last week in my piece on climate change and wind, I have no meteorological data to support any of my ideas. They are personal observations that our rainfall/snowfall patterns are slowly changing, which may have a far greater impact than temperature changes on the future environment here in the Adirondacks.

Next week I will present my views on the temperature change aspect of global warming.

Photo: Sedimentation of the English Brook delta in Lake George in November 2010 (Courtesy the Lake George Association).

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Tom Kalinowski is an avid outdoor enthusiast who taught field biology and ecology at Saranac Lake High School for 33 years. He has written numerous articles on natural history for Adirondack Life, The Conservationist, and Adirondack Explorer magazines and a weekly nature column for the Lake Placid News. In addition, Tom’s books, An Adirondack Almanac, and his most recent work entitled Adirondack Nature Notes, focuses on various events that occur among the region’s flora and fauna during very specific times of the calendar year. He also spends time photographing wildlife. Tom’s pictures have appeared in various publications across the New York State.

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