Susie and I are celebrating our Golden Anniversary this year by marking things off our “bucket list”. We booked a land-sea cruise to Alaska during the last couple of weeks of May.

Susie and I are celebrating our Golden Anniversary this year by marking things off our “bucket list”.  We booked a land-sea cruise to Alaska during the last couple of weeks of May.      
We arrived at Glacier Bay sometime during the early morning of Tuesday May 25, 2017.    As we walked on the ship’s observation deck, we enjoyed the magnificent snowcapped mountain views in the Bay.
In the afternoon we were out on deck to view Margerie Glacier.  The adjacent Grand Pacific Glacier has receded since we last saw it in 2005.  Where it had covered the entire north end of the bay, there now stands a huge mound of rock and earth that the glacier has pushed down to the water’s edge  I could not have imagined that 12 years later all of that ice would have receded up the valley! Is it a sign of global warming?  Probably, since we hear that glaciers all over the world are receding, and that melting ice has resulted in global sea level rise of about 8 inches in the last century.  
According to NASA, the Earth's climate has changed throughout time.   There have been seven glacial advance and retreat cycles in the last 650,000 years.  Most of these climate changes are due to very small variations in Earth’s orbit which changed the amount of solar radiation received at any specific point on Earth.
Satellites and other technological advances have enabled scientists to collect many different types of information regarding our planet and its climate.   This data reveals signs of a changing climate.
In the 1860s physicist John Tyndall recognized the Earth's natural greenhouse effect.  He suggested that slight changes in the atmospheric composition could bring about climatic variations. In 1896 Swedish scientist, Svante Arrhenius, discovered the heat-trapping nature of carbon dioxide and other gases. Thus, it was postulated that increased levels of these gases must cause the Earth to warm in response.  This is particularly significant since much of the warming trend since the1950’s is likely to be the result of human activity.  
The National Research Council (NRC) stated that evidence in ice cores from Greenland and Antarctica, show that the Earth’s climate responds to changes in greenhouse gas levels. Further the NRC said that evidence can also be found in tree rings, ocean sediments, coral reefs, and layers of sedimentary rocks. This ancient evidence reveals that current warming is occurring roughly ten times faster than the previous average rate of warming.
The average surface temperature of the Earth has risen by about 2.0 degrees Fahrenheit since the late 1800s, a change driven largely by increased carbon dioxide and other man-made emissions into the atmosphere.  Most of this warming occurred in the last 35 years, with 16 of the 17 warmest years on record occurring since 2001 with 2016 being the warmest year on record.  
Winters here in Neosho have been warmer, snow has been rarer, and spring is arriving earlier than normal these past few years.  I must admit that I enjoy this warmer winter weather.  However, these warmer winters are creating mismatches within natural communities where plants and animals have difficulty adjusting their life cycles.    
Thus, the Alaska glaciers are retreating, along with glaciers everywhere around the world.  Sea levels are rising.  Ecosystems are being disrupted.  Today we have the luxury of enjoying an extra 2 degrees average temperature during our winters, with many people continuing to deny that global warming exists.   We have to wonder what kind of tomorrow we are creating for our children and grandchildren.  

Gary Smith writes a column for the Neosho Daily News.