In Perspective - Global Temperatures

Harry Applin

In February there was an outpouring of critics that claimed that the snow storms in the mid-Atlantic states were a proof that climate change was a myth. There was also the line in a 3,000 page 2007 International Panel on Climate Change that said that the Himalayan glaciers would be gone by 2035 and of course there were the 2,000+ emails that had four words that definitively proved that climate change was a myth.

I am not going to defend any side of this debate but to say that the Himalayan glaciers are melting, a snow storm doesn't prove anything and that illegally gotten emails have gone through two different independent reviews and they found nothing inappropriate except for the wording. What I would like to do is explain the situation with global temperatures.

Anyone that watches the weather channel has noticed that every day they give the day's average high and low temperature. In February that average was about 30 F for the high and 14 F degrees for the low. The average temperatures for the beginning of March are 39 F for a high and 17 F for the low. These temperatures are collected from around the world and here in the U.S. where there are around 2,000 locations. These are the temperatures that are then averaged and compared to the average temperature for the last 100 years.

As the graph shows there have been a sharp increase in the average global temperature in the last 30 years and over the last 100 years that has been about 1.5 F degrees. There are two important trends that need to be pointed out. The first is that the temperatures were actually dropping up to the early 1900's. This led to speculation that we were headed into a new ice age. But after the early 1900's there is a marked increase in global average temperatures. Even when there is a drop in the average temperature around 1955 it doesn't reach the highest temperature in the last 1000 years. After that drip in temperatures the average global temperature then jumps another 0.75 F degrees. It is this point that has scientists worried. These temperatures are undisputed. (Graph provided by Pennsylvania State University Department of Meteorology and Earth and Environmental Systems Institute)

There are other indicators that reflect the trend. Both Spring and fall have been extended a week each over the last 30 years. The tropical rain band that circles the globe has grown hundreds of miles wider over the same period. The armadillo, a creature that dates back millions of years, has been moving out of its tropical rainforests and slowly moving north at a rate of about 40 miles a year. They have been sighted as far north as southern Nebraska, southern Illinois, and southern Indiana and are expected to be seen in Ohio, Pennsylvania and as far east as Rhode Island in the near future.

And what about the snow? The annual snow cover extent (SCE) over the Northern Hemisphere lands averaged 24.4 million square kilometers in 2008. This is 1.1 million sq. km less than the 39-year average and ranks 2008 as having the 4th least extensive cover on record. Another indicator is the Arctic sea ice extent average for February 2010 was 5.63 million square miles. This was 409,000 square miles below the 1979 to 2000 average for February. In perspective that is about the size of Texas and California combined. At the other pole, recent satellite data, which measures changes in the gravity of the ice mass, suggests that the total amount of ice in Antarctica has begun decreasing in the past few years. Even the Greenland Ice sheet has retreated by 30%.

It is this evidence that has scientists worried. There is no politics with these facts, but the repercussions could be devastating. The oceans have also shown a 1.5 F degree increase in temperature. The warming of oceans is significant since it takes much more energy to warm the waters than it does the air. It is this fact that makes scientists warn about stronger storms and hurricanes. While the warming air allows for more moisture content that can bring on larger downpours and higher snow fall totals in the winter. There are hundreds of indicators that all point to the same thing and all of it has been documented. The only debate has been brought by the industries that produce carbon and they are trying to protect their bottom line.