News
ENLARGE
In 1970 I was working on my oceanography degree at the University of Washington. It was my introduction to the idea of global warming and climate change. There was an irreverent anecdote making the rounds amongst students and faculty that gave the global warming story an interesting twist. It went like this:
In the beginning God created the heavens and the Earth. Plants were God's favorite life forms. He was the ultimate master gardener. He provided the plants with everything they needed, including an atmosphere with just the right amount of carbon dioxide (CO2). The plants absorbed the CO2 into their bodies during growth. When they died, the CO2 was released back into the atmosphere so other plants might live. The CO2 also trapped the sun's warmth close to the ground, protecting all life forms from the cold harshness of deep space.
God was a busy guy and had other stuff to do, so He left the Earth to evolve as it would. When He returned a few billion years later, He was dismayed to find the Earth in the depths of an ice age. Much of the carbon dioxide had vanished and His plants suffered mightily. He found the lost carbon in dead plant material that had been buried underground by geologic forces over all that time. Under heat and pressure it had become coal and oil. “How can I get all that carbon back into the atmosphere to feed the plants and warm the Earth?” He asked. So God created Man.
Early in the 1900s scientists realized that the Earth had gone through at least one ice age and perhaps more. They discovered the cycles in Earth's orbit and tilt had a good correlation with the length of the ice age cycle due to changes in the solar energy hitting the planet. It became known as the Milankovitch hypothesis, named after one of its advocates. It appeared a full cycle was about 100,000 years.
In 1970 new technologies were being focused on the question. Computers were good at precisely calculating the movement of the Earth and changes in solar energy. Data from deep sea sediment cores was coming in. This was our professor's area of expertise. These contained a climate record that went back several million years. Not only was the Milankovitch hypothesis confirmed, a much more complete climate record came into focus. Seventeen ice age cycles have been completed in the last 2 million years according to these records.
Where does the year 2009 fall in the latest cycle? We are in the warmest period known as the interglacial. The ice sheets have receded to the poles, making the climate favorable for human expansion. It has been so for about 11,000 years. If things go according to schedule, we should be seeing evidence of the next ice age. But things are not playing out as they should.
The journal Science in September published a study titled “Recent Warming Reverses Long-Term Arctic Cooling” that addresses this very question. Scientists analyzing layered lake bed mud, glacial ice, and tree rings from Alaska to Siberia have been able to reconstruct a detailed arctic temperature record going back 2,000 years. As predicted by the normal cycle, the arctic was cooling one half a degree Fahrenheit per 1,000 years. Then, in the year 1900, the cooling trend reversed to warming. The reversal was sudden and strong. Then it intensified in 1950.The region is now 2.2 degrees warmer than in 1900.
“The slow cooling trend is trivial compared to the warming that's been happening and that's in the pipeline,” said the lead researcher. Another of the authors said, “The fast rate of recent warming is the scary part. With humans' clear and growing ability to alter the climate, we could easily skip the next opportunity altogether.”
Scott McKain is a member of the Douglas County Global Warming Coalition. He is retired from the Douglas County Health and the Building Facilities departments. He has a degree in oceanography. Send suggestions to sjmckain@gmail.com.
In the beginning God created the heavens and the Earth. Plants were God's favorite life forms. He was the ultimate master gardener. He provided the plants with everything they needed, including an atmosphere with just the right amount of carbon dioxide (CO2). The plants absorbed the CO2 into their bodies during growth. When they died, the CO2 was released back into the atmosphere so other plants might live. The CO2 also trapped the sun's warmth close to the ground, protecting all life forms from the cold harshness of deep space.
God was a busy guy and had other stuff to do, so He left the Earth to evolve as it would. When He returned a few billion years later, He was dismayed to find the Earth in the depths of an ice age. Much of the carbon dioxide had vanished and His plants suffered mightily. He found the lost carbon in dead plant material that had been buried underground by geologic forces over all that time. Under heat and pressure it had become coal and oil. “How can I get all that carbon back into the atmosphere to feed the plants and warm the Earth?” He asked. So God created Man.
Early in the 1900s scientists realized that the Earth had gone through at least one ice age and perhaps more. They discovered the cycles in Earth's orbit and tilt had a good correlation with the length of the ice age cycle due to changes in the solar energy hitting the planet. It became known as the Milankovitch hypothesis, named after one of its advocates. It appeared a full cycle was about 100,000 years.
In 1970 new technologies were being focused on the question. Computers were good at precisely calculating the movement of the Earth and changes in solar energy. Data from deep sea sediment cores was coming in. This was our professor's area of expertise. These contained a climate record that went back several million years. Not only was the Milankovitch hypothesis confirmed, a much more complete climate record came into focus. Seventeen ice age cycles have been completed in the last 2 million years according to these records.
Where does the year 2009 fall in the latest cycle? We are in the warmest period known as the interglacial. The ice sheets have receded to the poles, making the climate favorable for human expansion. It has been so for about 11,000 years. If things go according to schedule, we should be seeing evidence of the next ice age. But things are not playing out as they should.
The journal Science in September published a study titled “Recent Warming Reverses Long-Term Arctic Cooling” that addresses this very question. Scientists analyzing layered lake bed mud, glacial ice, and tree rings from Alaska to Siberia have been able to reconstruct a detailed arctic temperature record going back 2,000 years. As predicted by the normal cycle, the arctic was cooling one half a degree Fahrenheit per 1,000 years. Then, in the year 1900, the cooling trend reversed to warming. The reversal was sudden and strong. Then it intensified in 1950.The region is now 2.2 degrees warmer than in 1900.
“The slow cooling trend is trivial compared to the warming that's been happening and that's in the pipeline,” said the lead researcher. Another of the authors said, “The fast rate of recent warming is the scary part. With humans' clear and growing ability to alter the climate, we could easily skip the next opportunity altogether.”
Scott McKain is a member of the Douglas County Global Warming Coalition. He is retired from the Douglas County Health and the Building Facilities departments. He has a degree in oceanography. Send suggestions to sjmckain@gmail.com.
