Cumberland Times-News

July 20, 2013

Here are insights on change in climate

Bob Doyle, Columnist
Cumberland Times-News

— I recently purchased a slim paperback largely free of technical jargon on the contentious subject of climate change.

“Global Weirdness” by Emily Elert and Michael Lemonick was produced by Climate Change, a non profit, non partisan science and journalism organization.

The book was reviewed by Climate Change researchers in fields from ecosystems, climate statistics, energy systems and chemistry. In addition, each of the four chapters was reviewed by a number of external researchers, known for their expertise in climate or climate related fields.

This book is a Vintage paperback with an ISBN of 978-0-307-74336-7 (2012) and costs $15. This would be an excellent book for public libraries and all with an interest in our environment.

I have chosen to review this book as recent polls reveal that a sizable fraction of Americans now discount Climate Change and see it as a political issue rather than a scientific reality.

Chapter One is “What the Science Says”. Here are a few key ideas raised in this chapter. There have been great changes in the global climate in the past. About 650 million years ago, nearly all the Earth was covered by ice. This condition has been called “Snowball Earth.”

Go forward 500 million years to the Cretaceous period; at that time, there was practically no ice anywhere on Earth. There were then dinosaurs on Antarctica, Palm trees in Siberia and crocodiles in regions that are now north of the Arctic Circle.

Sea levels were hundreds of feet higher than today (as all the ice had melted). About 55 million years ago, the temperature rose 11 F, stayed high for about 100,000 years and then dropped back. How could science know such conditions?

The conditions in the distant past can be determined by a number of powerful scientific techniques, including isotope abundances in deep layers of oceanic sediments.

Oxygen has several forms including Oxygen 16 and Oxygen 18. As global temperatures rise, more of Oxygen 18 is incorporated in these layers. Conversely as global temperatures fall, less Oxygen 18 will be present.

If climate change is coming, then why can’t we adapt to it? Our distant ancestors who were hunter-gathers would just walk to another area and settle in their huts, caves etc.

But humans of today are rooted to their dwellings, their communication systems, their shopping centers, their roads, their places of worship, hospitals etc.

For the past 10,000 years, global climate has been quite beneficent, enabling a great increase in human population, from an estimated 5 million in 8000 BC to over 7 billion presently.

If there is significant climate several human generations from now, it won’t be easy for hundreds of millions of humans to shift their dwellings, power lines, roads, railroad tracks, airports, farms, and cities, as sea levels rise.

Sea levels have risen about a foot in the past century. This increase in ocean levels can be attributed to two main factors; the melting of ice in many areas as well as the expansion of the water itself.

The carbon dioxide content of our atmosphere has now reached 400 parts per million versus 280 ppm at the start of the Industrial Revolution in the early 1800s.

Some people say that this carbon dioxide rise is good as it helps trees and plants to grow. But scientists have known since the chemist John Tyndall’s work in 1859 that carbon dioxide traps heat near the Earth’s surface.

The more carbon dioxide in the air, the warmer it will get. How much warmer is not easy to predict. In the past 100 years, the average global temperature has risen by 1.4 F. But this increase is not uniform, it is higher in the polar regions where much of the world’s freshwater is stored as ice.

Other factors including the increase in water vapor in the atmosphere and the consequent increase in cloud formation will play a big role in climate change.

A skeptic reading this column, is probably asking the questions, “What should we do? Should we stop using our cars? Not air condition our houses in summer? and Not heat our houses in the winter?”

Injecting the need for immediate painful change is an clever way to convince many to doubt or deny science. My main point is that we should not go into the future in denial, thinking that conditions for our children, grandchildren etc. will be better than what we have today.

SKY SIGHTS AHEAD: This afternoon, the moon will be closest to the Earth, a condition called perigee (means closest to the Earth). The distance from the Earth’s center to the moon’s center will then be 56.2 times the Earth’s radius.

The brightest moon this month will be late this evening when the moon is highest in the south. Tomorrow evening the moon will be full, shining near the tail of Capricornus.

Some readers may have noticed the brilliant point of light low in the western dusk. This is brilliant Venus, whose approaches to Earth are closest of any two planets in our solar system.

Venus’ surface temperature (as measured directly by the U.S.S.R. Venera landing crafts ) is nearly 900 F. This is due to the tremendous concentration of Carbon Dioxide in Venus’ atmosphere. (Even if we burned all of our fossil fuels and plants, Earth could not get as hot as Venus. But billions of years from now, our swollen sun will bring Venus-like conditions to Earth.)

Bob Doyle invites any readers comments and questions. E-mail him at . He is available as a speaker on his column topics.