A. The Earth is Warmer because of Sunlight and Kirchhoff’s Laws on Radiation.
Introduction: This is a foundational issue. If you do not generally understand this issue, please blog or email Quorvita for further information.
The Earth’s surface warms during the day from the sunlight and cools by emitting infrared radiation back to space. Infrared radiation is demonstrated by placing your hand in front of a fireplace. The heat can be felt even if the glass doors to the fireplace are closed. This process is in accordance with Kirchhoff’s Radiation Laws.
The Earth also stores and releases massive amounts of heat from the oceans and land and in frozen ice sheets in the form of heat of fusion. This heat is exchanged over hundreds of thousands to millions of years.
The Sun emits radiation at all wavelengths including visible light, infrared, etc. The Earth’s solid and liquid features absorb radiation of all wavelengths. The Earth’s gases, on the other hand, absorb and emit radiation in accordance with its specific spectral profiles. Hence gases are far more restrictive and play a much smaller role in what they can and can’t do.
Because of the complexity of radiation in general, it is often helpful to use analogies. One analogy is a conventional greenhouse. Unfortunately, this analogy has been so overstated that most people, particularly the media, confuse it with real greenhouses, which is not the case.
Under Kirchhoff’s laws the absorption peak of radiation for a gas is identified by a particular wave length representing a temperature (Wien’s Law). In the real world the gases absorbs and emits a bell shaped distribution of wave lengths. The following analogy is used to explain this spectral distribution concept. A baseball pitcher that throws fastballs at 90 mph the majority of the time is typically classified as a 90mph fastball pitcher. But every batter knows that not all of the pitches are going to be 90mph fastballs. The pitcher may pitch one at 70mph or 100mph, a curve, and sometimes the ball may hit the ground and rolls across the plate at 5 mph. This is called a Gaussian distribution of pitches. This is an analogy and has nothing to do with spectral radiation distribution. The same is true for greenhouses, which have nothing to do with Kirchhoff’s radiation laws. The branded name of Greenhouse Effect is only an analogy like the baseball pitcher. The same is true for Greenhouse Gases. There is no such thing as Greenhouse Gases. The phrase is only a useful analogy. The gas inside a real greenhouse is air.
There is a big difference between the energy of sunlight (2.5 eV) and the energy of longwave infrared (0.1 eV). This is a large imbalance, but the incoming sunlight is from a dot in the sky, comes in at various angles, 30 percent is reflected, and is only active 8 to 10 hours a day. Whereas, the lower-energy infrared radiation is emitted from the Earth’s entire surface area 24 hours of the day.
Kirchhoff’s Radiation Laws
- First Law: A hot solid, liquid, or dense gas emits radiation at all wavelengths (“a continuous spectrum of radiation”).
- Second Law: A thin hot gas in front of a cooler background emits radiation at a discrete set of isolated wavelengths.
- Third Law: A thin cool gas in front of a hotter solid, liquid, or dense-gas background removes the radiation from the background source at special wave lengths..
Above quote is from Physics Rutgers University but it is quoted in many basic texts. [http://www.physics.rutgers.edu/~matilsky/documents/kirchoff.html]
Most people reading these laws have no idea what they mean. The first law states that solids and liquids emit radiation in a wide range of wavelengths. The second law is that a hot gas in front of a cooler background emits radiation at discrete wavelengths known as its spectral or absorption profile. The third law is that a cool gas in front of a hotter solid or liquid background absorbs radiation at its absorption profile. Hence atmospheric gases “emits and absorbs” radiation at its absorption profile. The compressed gases referred to in the laws are highly compressed and do not apply to gases in the Earth’s atmosphere.
Gases are far more restrictive than solids and liquids in how it handles radiation. In general, with respect to absorption of radiation, solids and liquids are large and gases are small.
The Sun (a solid, liquid or highly compressed gas) emits radiation at all wavelengths including gamma rays, visible light, infrared, etc. The Earth’s solid and liquid surfaces absorb and emit radiation at most wavelengths associated with its temperature.
Under Kirchhoff’s Radiation laws the absorption peak for gases occur at its predominate wavelength or temperature equivalent (Stefan-Boltzmann Law & Wien’s Law). But, being at its predominate peak does not mean it is exclusive. There is a Gaussian (bell shape) type distribution of wave lengths.
The Earth’s surface warms during the day from the sunlight and cools by emitting infrared radiation back to space. The sunlight is high energy (.5 µm = 2.5 eV) and warms the Earth. The solid and liquid surface emit infrared radiation at a lower energy, i.e. short-wave (1.4 to 3µm = .88 to .41eV), medium-wave ( 3 to 8µm = .41 to .15eV) and long wavelength (8- 15 µm = 0.15 to .08eV and there are even lower energy long-wave infrared radiation. Although there is 3 to 31 times more energy in each sunlight photon over short and long-wave infrared photons, there are some offsetting features. The sunlight shines 8 to 10 hours per day with 30 percent beings reflected away by clouds and ice covered poles, plus the incidence angle at the polar ends reduce the amount of direct radiation. The infrared radiation, on the other hand, is emitted over the entire surface area of the earth and operates 24 hours a day. Sunlight overwhelms the infrared during the daylight hours with the opposite effect occurring at night.
The Earth constantly tries to balance these differences. It does it mechanically by wind, rain, snow, evaporation, freezing, etc. Radiation also works to balance the difference. Radiation energy increases by the 4th power (T4). An illustration of something to the fourth power means that the number is multiplied by itself four times. The number 10 to the 4th power would be 10.000. Hence, any increase in temperature causes the Earth to cool much faster and illustrates a self-modulating feature. The Earth also stores massive amounts of heat in the liquid oceans and land masses. This heat is stored and released over hundreds of thousands to millions of years to regulate the earth’s temperature.
Another aspect of Kirchhoff’s laws is that certain types of gas molecules absorb and re-emit infrared radiation. This has the effect of slowing down the heating and cooling process. This is a good thing.
These infrared absorbing gases (currently called greenhouse gases) and their absorption profiles are shown in the following two figures: Most of these gas molecules have absorption spectra that cannot significantly absorb infrared radiation with wave lengths between 8 to 14 microns (µm). These wave lengths have an equivalent peak temperature between +150°F to -90°F. That is, molecules at a temperature of +150°F will emit infrared radiation with a wavelength of 8 and molecules at -90°F will emit at a wavelength of 14 microns. This zone is referred to as the Infrared Window since radiation at those temperatures will pass through the atmosphere and into space without significant absorption. These points are illustrated by the two figures displayed below.
Scientists theorize that only 15 to 30 percent of the outgoing radiation is released through this Infrared Window. Since radiation travels at the speed of light, it occurs instantaneously over the 24 hour period. This wide gap of 15 to 30% (illustrating an error as high as100%) indicates that scientists really do not know the exact amount.
Studies have reported that 99% of the outgoing infrared radiation from the earth has a wavelength between 4 and 50 microns. [https://en.wikipedia.org/wiki/Outgoing_longwave_radiation] This corresponds to a temperature range of 451°C (850°F) to -215°C (-350°F). This is far too broad as there are very few locations on Earth that have these outer temperatures. The more likely infrared zone would be longwave radiation between 6µm and 20 µm (Temperature equivalent of +194°C to -128°C) In both bands, water vapor dominates the spectral chart followed by Carbon Dioxide at the colder temperatures (-50°C to -97°C)
G. S Callendar, one of the founding fathers of the Greenhouse Effect stated in his scientific publication [Callendar G. S. (1938) The Artificial Production of Carbon Dioxide and its Influence on Temperature, Q J.R. Meteorol. Soc Vol 64, 223-237] at page 225:
“The loss of heat from the earth’s surface and atmosphere is nearly all carried upon wave lengths greater than 5µ, the maximum intensity being at about 10µ.”
Hence the maximum intensity is below CO2’s absorption profile and in the middle of the Infrared Window. A wavelength of 10 µm represents a temperature of 16°C (62°F). The infrared window is where gases do not absorb this radiation. The radiation passes directly from the Earth’s surface to space. There are exceptions for atmospheric particles that reflect, absorb, and re-emit infrared radiation.
Callendar analyzed data from the Artic where the carbon dioxide concentration exceeds the water vapor concentration. At these cold temperatures most of the water vapor freezes out as snow. This represents an ideal environment that could have validated his CO2 hypothesis. However, he disregarded this data because the observations did not fit his hypothesis. He felt that the wind patterns in the Artic was probably why the temperature deviations were larger than expected. It raises a major problem with his study. There are wind patterns over the entire surface of the Earth, not just the poles. Callendar did not consider or take into account winds, convection currents, deviations in cloud and reflective surfaces, or any orbital changes on his CO2 data analysis.
Concentration varies with Altitude. Carbon Dioxide has a higher concentration (.04%) in the Stratosphere over water vapor (.001%). But both concentrations are exceedingly small. Methane is even smaller with amounts measured in the parts per billion. The dominate gases in the Stratosphere are nitrogen (78%), oxygen (21%) and Argon (0.93%). The lower Stratosphere and upper Troposphere is where many scientists, particularly in the IPCC, believe is where of the Greenhouse Effect based on CO2 has its greatest effect. However, as discussed under Question # 7 relating to Mars there are major problems with the upper altitudes because the air is too thin to have a significant effect particularly when combined with the exceptionally low CO2 concentrations (0.04%). At this low density and concentration, most of the infrared radiation should pass through the upper atmospheres without encountering too many CO2 molecules. For example, the probability of hitting a CO2 molecule in the Stratosphere is 140 times less than the chances of hitting a CO2 molecule on Mars. The cold Mars (-80° F) is cited as an example of an atmosphere being too thin for the Greenhouse Effect to function even though the CO2 concentration on Mars is 95% (2375 times more than in the Stratosphere.)
There are many factors that operate to heat and cool the Earth’s atmosphere other than a proposed Greenhouse Effect model based on CO2.
Water Vapor Dominates the Absorption/Emissions in the Troposphere. Water vapor is some 40 to 50 times more concentrated (3 to 5% as opposed to 0.04% for CO2) and has an infrared absorption profile as much as ten times larger. This is discussed above and in Question # 9 on Greenhouse Gases.
Particles & Liquid Droplets Act as Absorbers. There are large amounts of water droplets and ice particles in the clouds and a considerable amount of particulate matter floating around. Almost all liquid and particulate matter absorb and reflect most wave lengths. Liquid water in the form of clouds constitutes a large portion and equal to about 10% of all water in the atmosphere. These droplets absorb all spectra wave lengths but emit low energy infrared based on its equivalent temperature. Clouds range in altitude from 2 thousand feet (wavelength 10 microns, Temp 50°F) to 45 thousand feet (wavelength 13 microns, Temp. -60°F)
Biology Cannot be Ignored. Another factor that must be considered is Biology as it relates to the atmosphere. Biology is responsible for almost all the oxygen in the atmosphere, all marble, limestone, and other carbonate minerals on land and in the seas. It is the greatest contributor to the CO2 concentration. To illustrate how massive it is the collective weight of all humans on Earth is about 350 million tons. The weight of just ants and termites is twice that at 745 million tons. There are a million inspect species. [Nelson & Nelson] But this is insignificant compared to bacteria and single cell life which constitute between 350 to 550 billion, with a “B”, tons. This biological life increases with temperature.
Land and marine plants absorb sunlight reducing the heating component. As the temperature increases, land and marine plants flourish and cool the planet. There is biological life in the atmosphere as well. Up to 10,000,000 CFU per cubic meter of bacteria and fungi reside in the atmosphere [Whon, et. al. (2012) Metagenomic characterization of airborne viral DNA diversity in the near-surface atmosphere. Journal of Virology. 86(15):8221–8231.] and up to 1000 spores per cubic meter [Prussin, et. al. (2015) Total Virus and Bacteria Concentrations in Indoor and Outdoor Air, Environ Sci. Technol Lett. 2(4) 84-88 ] There are microorganisms surviving in the Stratosphere as well [Khodada C et. al (2015) Exposing Microorganisms in the Stratosphere, Astrobiology Science Conference, pg. 7447]. Solid bacterial masses absorb and reflect essentially all wave lengths or temperatures of radiation, not just infrared. This massive bio-system is self-regulating and has been this way for hundreds of millions of years.
Mechanical or Physical Temperature Moderators. Heat is transferred by convection (winds), conduction (direct contact with the surface), evaporation (1 calorie raises one gram of water 1°C, but it takes 580 calories to evaporate 1 gram of water without any temperature increase), freezing, (similar to evaporation), etc. Convection is the dominate heat transferred mechanism within the atmosphere. The oceans can store enormous amounts of heat energy for hundreds of thousands to millions of years and release that energy to modulate a constant temperature. One cubic meter of water can store 3000 times more heat than one cubic meter of air. Like the oceans, land and everything on the land can absorb, store and release heat. And like water, land holds and releases heat when needed. One cubic meter of land can store some 2500 times more heat than 1 cubic meter of air. Ice stores energy in the form of heat of fusion and absorbs and releases this heat over thousands to millions of years to modulate the temperatures. The modulating effects of land, oceans and ice is likely the major reason why the Earth retains and regulates its temperature.
The earth is self-regulating and inferences of a run-away environment are not supported by facts. The Glen-Fergus figure illustrates the geologic history over the last 550 million years as is shown in Questions 1 and 2. The alleged “run-away earth” scenario has never happened and the chances of it happening is as remote as the Earth being struck by a planet sized object. Even the snowball Earth Hypothesis has been debunked. [New Evidence Puts Snowball Earth Theory Out in the Cold, Science Daily, 25 March 2007, http://www.sciencedaily.com/releases/2007/03/070323104746.htm.%5D
Orbital Deviations are a Dominate Cause for Temperature Swings. Astrophysicist Milutin Milankovitch plotted the changes in the variations of the Earth’s orbit around the sun and the moon’s orbit around the earth. Every 90,000 to 100,000 years the orbit changes from being nearly circular to highly elliptical. This changes the amount of radiation hitting the Earth by 20 to 30%. This is a slow transition but has a dramatic effect on the temperature of the Earth. It is the cause for the ice ages and why the ice ages last so long. In addition, the Earth changes its axial tilt every 40,000 years known as Obliquity. The third deviation affecting the Earth is the Precession that changes are variable. Apsidal precession is the major cause of climate oscillations every 19,000 to 23,000 years. Einstein’s Theory of gravitation predicts changes every 100 years. Nodal precession is caused because the earth is not a perfect sphere. There is a slight bulge at the equator. This causes deviations in the orbital nodes every 127 days. Lunar nodal cycles every 18.61 years and directly change the tidal levels on Earth. The moon is slowly moving away from the Earth at the rate of 1.3 feet per decade, which changes the tidal forces. Tidal changes affect the ocean’s thermal currents, which have a significant effect on weather and Arctic sea ice. The Earth’s rotation is slightly slowing (2.3 milliseconds/century) because of the moon’s influences. All of these orbital deviations do not occur at the same time. Transitions between these cycles constantly affect the amount of radiation and tidal forces acting on the Earth.
Ignoring Water Vapor, Particles & Liquid Droplets, Mechanical & Physical Temperature Moderators, Biologic Effects, and Orbital Deviations, and blaming 100% of the warming temperature above a black body on Carbon Dioxide is far too simplistic.