From Mensagenda - June 2007

The Future: The Greenhouse Effect

by Mary Abbey

Changes are occurring today that likely are due to the average temperature of the Earth increasing because of human activities. Right now the Superior National Forest in northern Minnesota is battling drought and fire. Is that because of global warming? That is difficult to say. We do know that weather patterns are changing and will continue to change. Much of the western United States is suffering from drought, as is the southeast. Studies in the Nebraska Sand Hills indicate that there have been droughts of more than 100 years in the past, so this may not be unusual. It certainly will influence populations settled in those affected areas.

Studies in the ‘90s indicate that the warmer the average temperature, the higher the insurance claims will be from storm damage. This week a 1.7-mile-wide tornado wiped out the town of Greensburg, Kansas. The F-5 tornado was the most intense storm to hit the U.S. in eight years. Was this due to global warming? The warmer the oceans the more energy is available for hurricane formation. Katrina quickly escalated when it entered the Gulf of Mexico and rode over the warmer-than-average water. Can we know for sure that global warming is the culprit? Probably not, but we will still suffer the damages and pay for the massive clean-up costs. I don’t think we can afford to ignore the possibility that our energy-intensive lifestyles may be contributing to these catastrophic events.

The overall average temperature of the earth has risen by about 1.0oF in the last century. That doesn’t seem like much, but there are millions of temperatures involved in that statistic. Many populations are experiencing changes due to this temperature increase.

In northwestern Minnesota, average winter temperatures have climbed by about 12oF during the past 40 years, and average summer temperatures have climbed by 4oF. The local moose populations are in decline, because the additional heat has increased their stress, making them more susceptible to parasites.

In the Arctic, polar bears are becoming the poster children of global warming. Many populations are presently very successful, but with the polar ice cap contracting at the rate of 9 percent each decade and spring coming earlier than normal, they will soon be in serious trouble. Polar bears must have ice in order to hunt.

In Alaska, the porcupine caribou herd is affected by the changing climate. Winters have warmed by 5.7 degrees, and their food plants green up 10 to 20 days earlier than what has been normal. Calving is good and summer survival high. Unfortunately, the lifespan of those plants remains the same. When these plants brown at the end of summer, the caribou are forced to move away from the coastal plains to the hills and mountains to the south, where mosquito predation is intense. They enter the stress of winter in poor condition and survival rates drop.

Even fungi are being affected. In England, 50-year records of fungi show that now they are fruiting twice a year, where it used to be once. Within ecosystems, species are being affected in a myriad of ways, and many will likely not be able to adapt to these rapidly changing conditions.

I have given only a sampling of changes that are occurring now. It is important that we get a handle on this problem before the consequences become more serious. So what can you and I do? I’m hoping that you all already know some answers to that question, but I’ll go over some simple solutions next time.