Evidence shows many swings in Earth’s temperatures

Last week I provided evidence on global warming.

In early February, the Intergovernmental Panel on Climate Change released a report stating that global warming is real and humans very likely are to blame due to the increased burning of fossil fuels.

Based on my own research over the past 20 years, I believe that global warming is part of a natural long-term climatological cycle, but we are enhancing the increases in temperatures. Whether our global temperatures continue to rise or eventually start to fall remains to be seen.

Despite the evidence for Earth’s recent climb in temperature, there are also many indications of global cooling.

Over the past 4,500 years, there have been 75 major swings in Earth’s temperature. Go to www.longrangeweather.com to see charts showing the major temperature changes.

To determine when and how severe each period of global warming or cooling was thousands of years ago, scientists have used lake-bed bathtub ring readings, tree-ring data, glacial ice core samples, and ancient writings from the Chinese, various Indian tribes and others.

No precise measurements can be provided, but we do have a good idea of the intensity of alternating warming and cooling cycles on Earth during the past 45 to 50 centuries.

According to Nigel Weiss, an honored scientist at the Department of Applied Mathematics and Theoretical Physics at the University of Cambridge, England, and past president of the Royal Astronomical Society, the sun’s energy is expected to decrease, eventually leading to global cooling.

In recent years, our sun has been the most active in about 1,000 years, which Weiss thinks contributed to recent increases in Earth’s temperature.

During the Medieval Warm Period (800-1300 A.D.), the sun was also very active. At that time, the Vikings colonized a lush Greenland, and Britain was a wine-growing country.

However, during large solar minimas, the Earth usually experiences massive cooling. The most recent event of major decreased solar activity was during the Little Ice Age in the 1800s.

Sunspots almost completely disappeared for 70 years, and the era was called the Maunder Minimum. During that time, New York Harbor froze solid, and the Vikings were forced to abandon an icy Greenland, which is still iced over today.

According to Weiss, the sun’s polar field is now the weakest since the early 1950s, and sunspot activity is expected to decline in the next five to 10 years.

Another big factor for global cool-downs is volcanic activity. During the coldest period of the Little Ice Age, there were four major volcanic eruptions.

With decreased radiation from the sun and large amounts dust and ash in the atmosphere, global temperatures dropped to as much as several degrees below the current global mean temperature of near 58 degrees Fahrenheit.

A recent example of how powerful a volcano can be was the massive eruption of Mount Pinatubo in June 1991. It’s well documented that global temperatures dropped 1.1 degrees Fahrenheit from mid-June 1991 to March 1992.

That huge explosion sent heavy dust and ash up to 55,000 feet into the stratosphere, blocking some of the incoming radiation from the sun.

Since 1991, volcanic activity has been relatively calm. Other eruptions since that time have not been big enough to send the large volumes of ash and dust into the upper atmosphere necessary to cool the planet.

However, it seems that volcanic activity has been increasing in Earth’s oceans, which may be one reason for the unusually high number of El Ninos (the abnormal warming of sea-surface temperatures) since the mid-1990s.

Although there are numerous reports of glacial melting, it’s been reported that ice in the center of Antarctica and Greenland is thickening. In New Zealand, local guides state the Franz Josef and Fox glaciers are expanding rapidly along with other glaciers in the Southern Alps.

And, let’s not forget the record snows this month in upstate New York and New England and the state of emergency declared in Pennsylvania due to ice 4 inches thick last week. Thousands were stranded up to 16 hours or more on Interstate 78 without food or water.

So what do you think? Go to www.spokesmanreview.com/polls/news/ and vote on this global warming issue.

We are also hosting a seminar on March 2 that features upcoming weather patterns over the next 30 years, plus how the weather affects businesses and the commodity markets. Go to www.longrangeweather.com for more information.

In the near term, we should still see a series of quick-moving storms that will give us more rain and snow, especially in early March. We may also see some strong winds as well.

Conditions should be a bit drier in April.

More details next week.