A PERSPECTIVE ON CLIMATE CHANGE, a primer for politiciansby Jonathan DuHamel on Sep. 08, 2011, under Climate change
Climate change is a major issue of our times. Concern is affecting environmental, energy, and economic policy decisions. Many politicians are under the mistaken belief that legislation and regulation can significantly mold our climate to forestall any deviation from “normal” and save us from a perceived crisis. This post is intended as a primer for politicians so they can cut through the hype and compare real observational data against the flawed model prognostications.
The information below is gleaned from the scientific literature. The data show that the current warming is not unusual, but part of a natural cycle; that greenhouse gases, other than water vapor, are not significant drivers of climate; that human emissions of carbon dioxide are insignificant when compared to natural emissions of greenhouse gases; and that many predictions by climate modelers and hyped by the media are simply wrong. There is no physical evidence showing that human carbon dioxide emissions have a significant effect on global temperature. Carbon dioxide is vital to life on earth and current atmospheric levels are dangerously low. Political schemes to cut greenhouse gases will have no measurable effect on temperature but will greatly harm the economy by impeding energy production and use.
THE CURRENT WARM PERIOD IS NOT UNUSUAL
The graph below, based on reconstruction from the geologic and historical records, shows that there have been several warm/cold cycles since the end of the last glacial epoch. The temperature during the Holocene Climate Optimum was 3ºF to 10ºF warmer than today in many areas. This is warmer than the extreme scenarios of the IPCC. Clearly, current temperatures are neither unprecedented nor unusually warm.
Looking at the broader geologic record, we see that there is little correlation between temperature and carbon dioxide.
Note that there was an ice age at the end of the Ordovician Period when atmospheric CO2 was approximately 4,500 ppm or more than 11 times the current level. Notice also that the “normal” temperature of this planet is 22 C, or about 18 F warmer than it is now.
For more details and references see: Natural Climate Cycles
But what about the ice core graphs?
These show a correlation between temperature and carbon dioxide. But what isn’t usually mentioned is that temperature changes PRECEDED changes in CO2 concentration by about 800 years. That’s because temperature controls carbon dioxide solubility in the oceans. Notice that the temperature cycles occur in approximately 100,000-year intervals. This coincides with the precession of the Earth’s elliptical orbit around the Sun. (Can you think of anything that would make CO2 cycle this way if it were the driver rather than temperature?)
For more information and references see: Al Gore’s Favorite Graph
Carbon Dioxide and the Greenhouse Effect
The “greenhouse effect,” very simplified, is this: solar radiation penetrates the atmosphere and warms the surface of the earth. The earth’s surface radiates thermal energy (infrared radiation) back into space. Some of this radiation is absorbed and re-radiated back to the surface and into space by clouds, water vapor, methane, carbon dioxide, and other gases. Water vapor is the principle greenhouse gas; the others are minor players. Without the greenhouse effect the planet would be an iceball, about 34 C colder than it is. The term “greenhouse effect” with respect to the atmosphere is an unfortunate usage because it is misleading. The interior of a real greenhouse (or your automobile parked with windows closed and left in the sun) heats up because there is a physical barrier to convective heat loss. There is no such physical barrier in the atmosphere.
Carbon dioxide is a “greenhouse” gas, but its theoretical ability to warm the atmosphere (as shown on the graph) diminishes with increasing concentration. For instance, if a certain amount of carbon dioxide can cause a 1 degree temperature rise, it will take twice that amount to warm the next degree.
The reason it works this way is because carbon dioxide can absorb only a few specific wavelengths of thermal radiation. The current concentration of carbon dioxide has absorbed almost all available radiation in those wavelengths so there is little left for additional carbon dioxide to absorb. Water vapor absorbs many of the same wavelengths of thermal radiation decreasing the effect of carbon dioxide even more. That is why our proposed attempts to decrease atmospheric carbon dioxide will have almost no effect on temperature.
WHY THE CLIMATE MODELS ARE WRONG
The IPCC says that warming will produce more water vapor which will enhance greenhouse warming, a positive feedback. All their climate models are based on this assumption. Sounds reasonable, except in the real world it doesn’t happen. Increased water vapor produces more clouds which block the sun thereby inducing cooling, a negative feedback.
According to climate models, the rate of warming should increase by 200-300% with altitude in the tropics, peaking at around 10 kilometers – a characteristic “fingerprint” for greenhouse warming. However, measurements by weather balloons and satellites show the opposite result: no increasing temperature trend with altitude. In other words, the model-predicted “fingerprint” of anthropogenic, greenhouse warming is absent in nature. The computer-predicted signature of greenhouse warming trends should look like the graph on the left below, but according to measurements from satellites and radiosondes, the actual temperature trend is as depicted in the graph on the right.
The atmosphere is not static; we have weather which tends to dissipate heat into space. According to real world measurements, the negative feedbacks overwhelm the theoretical positive feedback posed by the IPCC.
The greenhouse model is a simplified story that helps explain how our atmosphere works. However, the real world is very complicated and still not fully understood. Even global warming alarmist James Hansen of NASA’s Goddard Institute for Space Studies, had this to say: “The forcings that drive long-term climate change are not known with an accuracy sufficient to define future climate change.” — James Hansen, “Climate forcings in the Industrial era”, PNAS, Vol. 95, Issue 22, 12753-12758, October 27, 1998.
And even the IPCC once admitted, “In climate research and modeling, we should recognize that we are dealing with a coupled non-linear chaotic system, and therefore that the prediction of a specific future climate state is not possible.” — Final chapter, Draft TAR 2000 (Third Assessment Report), IPCC.
HUMAN CONTRIBUTION TO GREENHOUSE GASES IS INSIGNIFICANT:
Human carbon dioxide emissions are 3% to 5% of total carbon dioxide emissions into the atmosphere, and about 98% of all carbon dioxide emissions are reabsorbed through the carbon cycle. http://www.eia.gov/oiaf/1605/archive/gg04rpt/pdf/tbl3.pdf.
We have all heard scary stories about global warming and, therefore, propose to limit our carbon dioxide emissions, assuming that they are responsible for the warming.
Using data from the Department of Energy and the IPCC we can calculate the impact of our carbon dioxide emissions. The results of that calculation shows that if we stopped all U.S. emissions it could theoretically prevent a temperature rise of 0.003 C. If every country totally stopped human emissions, we might forestall 0.01 C of warming. For the derivation of these numbers, see my post: Your Carbon Footprint doesn’t Matter .
Although Earth’s atmosphere does have a “greenhouse effect” and carbon dioxide does have a limited hypothetical capacity to warm the atmosphere, there is no physical evidence showing that human carbon dioxide emissions actually produce any significant warming.
The major greenhouse gas is water vapor which accounts for about 97% of the warming effect. The other 3% is attributed to carbon dioxide, methane, CFCs etc. Human carbon dioxide emissions represent about 3% of 3% of greenhouse gases or about one tenth of one percent of the total greenhouse effect and are therefore insignificant.
THE SUN IS THE REAL CLIMATE DRIVER
The real drivers of climate are the Sun’s insolation (light and heat), its magnetic flux, and the relative position and orientation of the Earth to the Sun.
There are three main positional variations of the Earth and Sun, called Milankovitch cycles: Orbital Eccentricity, Axial Obliquity (tilt), and Precession of the Equinoxes. These cycles affect the amount and location of sunlight impinging on the earth.
The variations in the Sun’s magnetic flux controls the amount of cosmic rays impinging on the atmosphere. Cosmic rays produce ionizations and the ions form nuclei for cloud formation. Cloud cover has a great effect on global temperature, but this area is still poorly understood and not addressed in climate models. For more detailed explanations of solar cycles and cosmic rays see my posts:
SHOULD WE BE CONCERNED WITH SEA LEVEL RISE?
Climate alarmists put forth scary scenarios saying that global warming is causing unprecedented sea level rise and the rise is accelerating. Well, don’t sell your beach-front property yet. Since the end of the last glacial epoch 12,000 years ago, sea level has risen 120 meters, about one meter per century. [NOAA puts normal rise at 1 to 3mm per year, about the thickness of a penny.]
The graph on the left above is a reconstruction of sea level rise since the end of the last glacial epoch (source). The graph on the right above shows satellite measurements of sea level. Notice there has been no acceleration of rise; in fact there has been a decrease in the rate of rise.
Research has shown that the rate of sea level rise in cyclic in response to the Sun’s internal 11-year cycle.
For more information see:
PROBLEMS WITH TEMPERATURE DATA
Climate alarmists and the media cherry-pick data to produce scary headlines. Official temperature records have been corrupted by deliberate manipulation, by siting deficiencies, and by ignoring inconvenient data. See:
There have also been problems with computer-read temperature data. For instance, Canadian mathematician Steve McIntyre, slayer of the IPCC’s infamous hockey stick graph, found a glitch in NASA Goddard Institute for Space Studies’ (GISS) computer program which calculates surface temperature. A little less than ten years ago, GISS changed the way it recorded temperatures. No one thought to correlate the old temperatures with the new ones, that is until McIntyre tried it, and he found a warming bias in the current calculations. NASA has since corrected the error.
Thus, the previous hottest year of the 20th Century, 1998, fell to second place; the hottest year is now 1934. Al Gore has claimed that 9 of the 10 hottest years occurred during the past decade. Under the revised figures, only three did. Four of the top 10 are now from the 1930s: 1934, 1931, 1938 and 1939, while only 3 of the top 10 are from the last 10 years (1998, 2006, 1999). Several years (2000, 2002, 2003, 2004) fell well down the list, behind even 1900.
Most of the warmest years occur well before the major 20th Century build-up of CO2. So where is the cause and effect?
Additional problems with official surface temperature readings were discovered by meteorologist Anthony Watts [see Surfacestations.org]. He found that many official weather stations were sited so as to produce a warming bias. Bad siting includes being near asphalt parking lots, next to buildings, being near air conditioning exhaust vents, and encroaching urbanization. Compare the station at the University of Arizona in 1923 vs. 2008 (see below). In 1923, the station was in an open area near lawns and dirt roads, but now, the station is in an asphalt parking lot between buildings. This change in site conditions has produced a warming bias.
More recently we have learned that a small group of scientists conspired to hide declining temperatures and manipulated official databases to show a warming bias.
See my blogs on the subject, the so-called Climategate scandals:
We often hear that increasing carbon dioxide in the atmosphere will make the oceans too acidic and dissolve or otherwise harm carbonate-shelled marine fauna. These writers or reporters seem ignorant of the fact that marine fauna evolved when the atmospheric CO2 concentration was more than 10 times higher than the current level.
It has been estimated that current ocean pH is 0.1 pH unit less alkaline than it was in recent pre-industrial time, and some climate models predict a further decrease of 0.7 pH units by 2300. However, proxy reconstructions of ocean acidity, based on fossil and modern corals, show that ocean pH has oscillated between pH of 7.91 and 8.29 during the past seven thousand years That is within the alkaline range (neutral is 7). That cyclic variation is nearly four times larger than the 0.1 decrease alarmists are whining about, and even if the model predicted decrease of 0.7 units occurs, the water will still be alkaline.
Many studies show that corals and other marine life is able to adapt to the changing pH.
For more details see: Ocean Acidification by Carbon Dioxide
The basic conclusion is that carbon dioxide has little effect on climate and all attempts to control carbon dioxide will be a futile exercise in climate control. All the dire predictions are based on flawed computer models. Carbon dioxide is a phantom menace.
No researchers nor the IPCC have presented any physical or observational evidence that CO2 is a significant driver of temperature.
Climate models are complex mathematical constructs. But the atmosphere is even more complex, so modelers must ignore many variables such as Sun-Earth relationships and clouds, in favor of a few basic parameters. The fundamental assumption of climate models is that changes in CO2 concentration drive temperature change, but evidence from geology and astronomy show that the relationship is just the opposite.
Climate modelers also assume that the pre-industrial concentration of CO2 was below about 280 ppmv and that the current value of about 380 ppmv is unprecedented. But that assumption is shown to be wrong by several lines of evidence including direct measurements made since the early 1800s. CO2concentration has fluctuated widely during the last 10,000 years and has often exceeded current levels. . [Sources: Beck, E., 2007, 180 Years of Atmospheric CO2 Gas Analysis By Chemical Methods, Energy & Environment Volume 18 No. 2 and Kurschner et al., 1996, Oak leaves as biosensors of late Neogene and early Pleistocene paleoatmospheric CO2 concentrations, Marine Micropalaeontology, 27:299-312.].
Models, when tested by running in hindsight from the present, cannot reproduce the Medieval Warm Period nor the glacial epochs. The U.N. IPCC claims that the surface temperature rise in the last 130 years has been 0.6 C ± 0.2 C. That is a 33% margin of error in each direction. The standard for statistically significant scientific findings is 5% in each direction. The large margin of error reflects the uncertainty of the basic measurements from weather stations and the methods of averaging the data.
Climate modelers make some outlandish predictions, but occasionally there is a glimmer of honesty:
“The forcings that drive long-term climate change are not known with an accuracy sufficient to define future climate change.” — James Hansen, “Climate forcings in the Industrial era”, PNAS, Vol. 95, Issue 22, 12753-12758, October 27, 1998.
“In climate research and modeling, we should recognize that we are dealing with a coupled non-linear chaotic system, and therefore that the prediction of a specific future climate state is not possible.” — Final chapter, Draft TAR 2000 (Third Assessment Report), IPCC.
While controlling CO2 emissions from burning fossil fuels my have some beneficial effects on air quality, it will have no measurable effect on climate, but great detrimental effects on the economy and our standard of living. The greatest danger of climate change is that politicians think they can stop it. But the climate has always been in a state of flux. In my opinion, the debate over global warming is truly a scam designed to control (and tax) production and use of energy from fossil fuels.
“The whole aim of practical politics is to keep the populace alarmed (and hence clamorous to be led to safety) by menacing it with an endless series of hobgoblins, all of them imaginary.” – H. L. Mencken
For more background on climate science, see the Climate section of my ARTICLE INDEX page.