Understanding Climate Change: Should We Be Worried?
The subject of global warming is a difficult topic to write about. In general, many readers do not understand what is really going on and it is very hard to determine who is right on this topic. It’s also extremely difficult to check it out yourself. On the one side, you have Al Gore and thousands of climate experts claiming that we simply better act now or it will be too late. On the other hand, some scientists with very good resumes are claiming it’s all a hoax; we have nothing to fear. Others claim that recent warming is entirely due to natural causes. A major voice in the climate movement, Dr. James Hansen, is saying we better shut down the coal plants now. Others, including some of our representatives in congress, do not want to upset the apple cart. How can we, as citizens who care what kind of planet we leave to our children, take a stand one way or the other?
I had decided to write a column on this subject quite a while ago, but the sheer volume of noise coming from climate skeptics was clouding the story. A flood of climate skeptic websites started showing up and articles published prior to the UN Climate conference in Copenhagen and after the US House of Representatives passed the energy bill. My immediate goal was to get to the bottom of this story and convince myself who I should listen to. After all, I do have a couple of engineering degrees and can follow some of the technical papers written on the subject.
A few weeks ago, I bought a copy of Dr. Hansen’s new book “Storms of Our Grandchildren.” Having read some of his work, as well as his detractors, I hoped it would clear up some details and let me write my story. After reading his book, I reached two major conclusions. One is that I better start getting really, really, worried! This situation is a whole lot scarier than most of us have realized. The second conclusion was a discovery that he is not exactly in sync with others on the topic. Parts of the proposed energy legislation may not be the right thing to do.
Most of the players in this argument agree that the world’s average temperature is rising over the last century. There also seems to be a consensus on carbon dioxide (CO2) concentrations in the atmosphere today. We have seen an increase from 315 ppm (parts per million) to 380 ppm over a span of only 50 years. (Unless otherwise noted, all of the claims in this article come from Hansen’s book where their original sources are clearly documented.)
Digging a little further, I found a web site (Google “List of scientists opposing the mainstream…”) that lists the principal skeptics; organized on the basis of where they are on the subject. Admittedly, this may not be the most accurate listing available, but it serves my purpose. The website claims that these are all scientists with peer-reviewed, published works in “natural science” journals. Of those on this list, only a few deny that the earth is getting warmer. A few more simply disagree with the accuracy of the IPCC projections or still feel the cause of global warming is unknown. However, there remains a large number of very qualified scientists who think Hansen; et al, are wrong. Who can we believe and why is there so much difference of opinion? Are most of these “authoritative skeptics” somehow influenced by the energy lobby? These questions are significant because these skeptics are trying to influence congressional action. It is this group that is at total odds with Dr. Hansen and is causing me to loose some sleep. Is there really a conspiracy and if so, who are the guilty parties? Is the accepted science really wrong? Tough questions indeed!
The skeptics, not counting the minority that continue to argue the earth is not getting warmer, have no other way to explain global warming other than to say the sun is responsible. They claim that solar irradiance that hits the earth varies over time and is a natural phenomenon that has no bearing on human activity. Some have gone to great lengths to explain how changes in the earths tilt and orbit are the simple cause of our warming. They all point out that plots of CO2 concentrations over the previous 400,000 years show CO2 peaking just after the peak temperatures. Dr. Hansen actually agrees with this and explains it very well. Interestingly, a plot of this data, obtained from Antarctic ice cores, does look like a fairly regular cycle of events. Note that during the first 399,900 years of this period, the level of CO2 in the atmosphere was less than 280 ppm. That was 100 ppm lower than today’s level.
The major temperature spikes of the last few hundred thousand years may be partially explained by solar factors. The repetitive changes in the earth’s axis tilt follows a cycle with a period of 41,000 years. The earth is also in an orbit that is not exactly circular; with a variation that goes though a cycle of around 100,000 years. A more rapid solar phenomenon is the 10-12 year solar cycle driven by solar activity. Many global warming skeptics argue that we are now in a period of increasing solar irradiance due to these factors. If we are, and this increased solar power is increasing the CO2 levels, then we have our answer. CO2 is the cart that follows the horse. We are not making the planet warmer. Who cares if CO2 is higher today because of carbon emissions? Any warming, they claim, is due to the sun.
After reading “Storms,” which contains a composite plot of solar irradiance from 1975 to 2009, I discovered a bit of a surprise. This curve clearly exhibits a 10-12 year solar cycle, but we are now at the “coolest” phase of this cycle. We are also 8,000 years away from the coolest point (for northern hemisphere ski areas) in the 41,000 year “earth axis tilt” cycle. The sun’s irradiance is lower than it ever was in thousands of years and has not caused any recent increase in the amount of energy that is hitting the earth. How can we say the sun is raising CO2 factors higher than it ever did before? How can we argue that it’s getting warmer because of the sun when the sun’s radiation is at its low point?
In reality, we have cooled slightly in recent years because of this 10-12 year solar cycle on top of the recent La Nina, but the overall temperature trend remains slightly upward when you look at temperature history over the last hundred years. I must point out that there are many who say this “trend” is fabricated evidence and part of the conspiracy. If so, why are the glaciers melting? Why have we seen such an outbreak of pine beetles when “normal” winters used to keep them under control? Why is there talk of a real Northwest Passage?
In addition to claims of high solar irradiance causing our warming, many skeptics argue that CO2 cannot possibly warm the planet. This is simply not true. Any physicist can prove CO2 (and methane) does absorb radiation. We have concrete science that demonstrates how gases such as CO2 absorb infrared radiation that is radiated from the earth. The mechanics of how this works seems to be the center of a lot of this debate, but it is very clear. While water vapor allows some infrared radiation to escape, CO2 clearly blocks parts of the infrared spectrum; causing our planet to heat up. This is causing our average temperatures to creep up to the extent that we may have already cancelled out the next ice age.
Dr. Hansen and others are alarmed for good reason. They are seeing major increases in the melting of Arctic and Antarctic ice sheets; a fact they did not predict would happen this fast. They are being attacked by fringe media, energy industry, and private party skeptics who claim that the last few years “prove” we are not warming up. Dr. Hansen’s detractors should admit that perhaps they are missing something. Perhaps one of them can show us how the sun is making things warmer today, not 30,000 to 40,000 years ago. If there are other major theories hidden in the denier literature that are not related to the sun, I apologize in advance for missing this fact.
The scope of Dr. Hansen’s book is far beyond what I expected, and far beyond what one can cover in a single article. I can see how he has so many detractors. Some of them, including some major environmental groups, do not support his view that fast nuclear reactor technology may be a way out of this mess. He even disagrees with the cap and trade folks. With Greenpeace and Congress against him, what chance does he have?
Perhaps it is because Dr. Hansen writes as if he really cares and clearly has the credentials to argue his case; I’m convinced that we better listen to this guy. Anyone who wants to know what we can and should do about climate change should pick up a copy of “Storms of Our Grandchildren” and find out. Then tell your representatives in congress to do the same.
Dave Yost is a retired Distinguished Member of Technical Staff at Bell Labs, most recently employed by Lucent Technologies. He has a BSEE from Drexel University and MS in Engineering from Brown University. He and his wife Carol now live in Williams Bay, Wisc. and Silverthorne.
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