Mars

Global warming on Mars, Neptune and Pluto

Over the last 50 years or so, Earth’s average temperature has, by some accounts, risen about one degree Fahrenheit. During this same time, global warming has been observed on Mars, Neptune, Neptune’s moon Triton, and Pluto.  Is that just coincidence or are natural cycles at work?

Proponents of anthropogenic global warming (AGW) claim that human carbon dioxide emissions are the main cause of recent warming on Earth. I have yet to see any compelling physical evidence to support that hypothesis.

There is, however, physical evidence that Earth’s temperature and climate are controlled by cyclic changes in the Sun’s luminosity and magnetic field.  There is also physical evidence that Earth’s global temperature and climate are related to the Earth’s position relative to the sun.  These positional relationships include variations in orbital eccentricity, and variations and magnitude of axial tilt.  These cycles induce atmospheric oscillations that affect our weather and global temperature, and ultimately climate cycles. For a more detailed look at these cycles, see Ice Ages and Glacial Epochs.  Similar natural cycles are apparently at work on other planets too.

AGW proponents are under fire resulting from release of more emails in the “Climategate” scandals.  These emails show, as in the previous release two years ago, that a small cabal of influential scientists promoted the AGW line, schemed to suppress dissenting views, bullied journal editors, hid the decline, and in private expressed much more uncertainty than their public statements would connote. While we are waiting to see the fallout from recent revelations, I offer for your consideration  an essay by British scientist and engineer Dr. John Brignell titled: “How we know they know they are lying.”  Among other things, he discusses the difference between real science and bureaucratic science (BS): http://www.numberwatch.co.uk/lying.htm

A Nuclear Explosion on Mars

It has long been a mystery of why there is a super-abundance of uranium, thorium, and potassium on the Martian surface concentrated near Mare Acidalium in the region of the large, shallow depression. Also, the Martian atmosphere has an unusual amount of radiogenic isotopes.

An explanation for this Martian mystery was presented by Space Physicist John Brandenburg at the 42nd Lunar and Planetary Science Conference in Houston, TX this month. According to the press release, Brandenburg suggests, “evidence shows that approximately 180 million years ago the planet Mars was devastated by a massive natural nuclear explosion. This natural event filled its atmosphere with radio-isotopes, irradiated its soil and atmosphere with neutrons, and spread a layer of radioactive material on the surface of Mars. His analysis estimates the force of the explosion to have been in excess of 1 million one megaton hydrogen bombs. This explosion created a region of enhanced radioactivity centered in the northern Mare Acidalium region at approximately 55N and 15 W.” You can read Brandenburg’s paper here.

If you think Brandenburg’s proposal is far-fetched, consider that something similar almost happened in Africa about two billion years ago.

In 1956, uranium was discovered in Oklo, Gabon, then a French colony. The uranium was mined and used in French nuclear reactors. Most uranium is the stable heavy isotope U-238 and has to be refined to recover the fissionable U-235. It was found that the uranium from Gabon was unusually depleted in U-235. Geologists investigated and in 1972 proposed that the U-235 was depleted because the Gabon deposits were the remains of a natural spontaneous nuclear reactor.

As explained by Andrew Alden, writing in about.com, geology:

What made such a thing possible was that in the distant past uranium was naturally enriched in U-235, that is, less of it had decayed away by nuclear fission. About 1.7 billion years ago, to be more precise, a natural deposit of uranium ore was radioactive enough to generate about 100 kilowatts of heat, off and on, for more than a million years.

Geologic forces gathered the uranium together. First a layer of sandstone was infiltrated by uranium-bearing groundwater, leaving a relatively thin sheet of uranium-oxide ore. Then the rocks were tilted, and as they eroded downward the groundwater concentrated the uranium minerals, sweeping them downward within the sandstone until a thick stripe of ore was built up. That’s when things heated up.

To understand what happened next, you need to know a little about nuclear reactors. The nuclei of uranium atoms normally decay with the release of energetic neutrons—so energetic that they fly away without interacting with other uranium nuclei. The neutrons need to be slowed down before they can start splitting other uranium nuclei, which release more neutrons and start a feedback cycle. Something needs to moderate the neutrons. The first artificial reactor, built in 1942, used balls of enriched uranium spread out inside a large pile of graphite blocks, which served as a moderator.

But water acts as a moderator, too. At Oklo there was a lot of water, probably a river flowing above the buried orebody. The water allowed the nuclear interactions to reach the critical point, and the reactor began to work. But as it heated up, the water turned to steam and flowed away. With the moderator gone, the chain reaction stopped and did not start again until the orebody cooled and the water returned. This simple feedback cycle kept the Oklo reactors (there were at least a dozen of them) active until the U-235 was depleted. That took about a million years. When the Oklo mine was producing ore in the 1970s it was that telltale depletion of U-235, unheard-of in nature, that tipped scientists off.

A remarkable thing about the Oklo reactors is that the highly radioactive waste products stayed put without the elaborate containment we use today on nuclear power plant waste. More than a billion years later, everything is contained within a few meters of its source.

Recently a team of scientists took advantage of this excellent preservation and studied the isotopes of xenon gas—a product of uranium decay—trapped in phosphate minerals at Oklo. Led by Alex Meshik of Washington University of St. Louis, they reported in 2004 that the reactor went through eight cycles a day, running for 30 minutes then shutting down for two and a half hours. The whole thing is reminiscent of geysers.

Why was uranium so much more radioactive then? With a half-life of 700 million years, U-235 started out making up nearly half of all uranium when the solar system began some 4560 million years ago. Many shorter-lived radioisotopes that existed in the beginning, like aluminum-26, have become extinct. We know of their former existence by the presence of their decay products in ancient meteorites—nuclear fossils.

The abundance of water in Gabon prevented a nuclear explosion. On Mars, however, it is hypothesized that the uranium deposit was much larger than that at Oklo, large enough to contain the errant neutrons after being triggered by a deep intrusion of groundwater.

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, so let’s examine its theoretical and actual effect on temperature.

co2greenhouse3Even the IPCC agrees that the hypothetical capacity of carbon dioxide to change temperature is given by the formula: Tc = áln(C2/C1), where Tc is the change in temperature in degrees Centigrade and the term ln(C2/C1) is the natural logarithm of the CO2 concentration at time two divided by the concentration at time one. The constant á (alpha) is sometimes called the sensitivity and its value is subject to debate. This relationship was proposed by Svante August Arrhenius, a physicist and chemist, around 1896. This logarithmic formula produces a graph in the form shown at the left. This shows that as the concentration of carbon dioxide increases, its effects have less and less influence. This graph is the pure theoretical capacity of carbon dioxide to warm the atmosphere in absence of any confounding feedbacks. The different curves represent different values of alpha.

 Radiation transmitted by atmosphereThe 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. Notice too, that water vapor absorbs many of the same wavelengths of thermal radiation. Also notice that in a certain part of the spectrum there is an open window of no absorption.

We see, therefore, that increasing levels of carbon dioxide in the atmosphere will have a decreasing hypothetical effect on temperature. That is also why our proposed attempts to decrease atmospheric carbon dioxide will have almost no effect on temperature.

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.

Dr. Roy Spencer explains here why doubling the carbon dioxide concentration in the atmosphere will add only 3% to Earth’s greenhouse effect. Spencer has further discussion here in which he says, “that about 50% of the surface warming influence of greenhouse gases has been short-circuited by the cooling effects of weather.”

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.

An example of negative feedbacks:

In 2001, a paper by M.I.T. researchers proposed that warming dissipated high-altitude cirrus clouds which had the effect of dumping heat into space, thereby helping to regulate earth’s temperature. This paper was controversial because it went against the orthodoxy of global warming and there were many detractors. However, in 2007 researchers from the University of Alabama, using NASA satellite data found evidence to support the theory. In 2009, the original M.I.T. researchers, using National Centers for Environmental Prediction’s 16-year (1985-1999) monthly record of sea surface temperature, together with corresponding radiation data from the Earth Radiation Budget Experiment, found more real world evidence in support of the theory (see PDF). It might be noted that 11 major climate models used by the IPCC assume positive feedback, but real world data shows a temperature-moderating negative feedback. However, the role of clouds is still poorly-understood and more real-world data is needed.

What happens on other planets:

Venus:

Venus has a surface temperature of about 900 F and an atmosphere composed of 96% carbon dioxide. The temperature is the same from equator to poles, from day to night (Venus rotates on its axis in 2,802 hours rather than 24 hours). Venus is often touted as the extreme example of run-away greenhouse warming. But, there is almost no greenhouse warming on Venus because little, if any, direct sunlight gets to the surface. The atmosphere is too thick. In 1975, the Russian Venus lander Venera 9 measured clouds that were 30–40 km thick with bases at 30–35 km altitude. The surface air pressure on Venus is about 92 times greater than that on Earth. The high pressure alone can explain most of the high surface temperature. Although Venus gets almost twice the solar irradiation of Earth, Venus’ high albedo reflects back 65% of the sunlight.

 Venus has almost no water vapor in the atmosphere (about 0.002%), and therefore lacks the major greenhouse gas that Earth has.

Mars:

Mars has an atmosphere composed of 95% carbon dioxide and only a trace of water. Its atmosphere is very thin. Its surface pressure is about 2% that of Earth. The temperatures on the two Viking landers, measured at 1.5 meters above the surface, range from + 1° F, ( -17.2° C) to -178° F (-107° C). However, the temperature of the surface at the winter polar caps drop to -225° F, (-143° C) while the warmest soil occasionally reaches +81° F (27° C) as estimated from Viking Orbiter Infrared Thermal Mapper (NASA data). Again, no water vapor, no greenhouse effect.

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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 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. (Source )

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. If you disagree with that statement, then produce some physical evidence to refute it.

UPDATE March 3, 2011: A new paper in Geophysical Research Abstracts (Vol. 13, EGU2011-4505-1, 2011) reports that detailed spectrographic analysis found that because of the overlap absorbance of the much more abundant water vapor for long wave radiation, the effective sensitivity of carbon dioxide and methane as greenhouse gases is only one-seventh that claimed by the IPCC and used in climate models.

Mars Images from University of Arizona HiRISE Project

Mars2Thousands of images of Mars are available from the University of Arizona’s High Resolution Imaging Science Experiment (HiRISE), see here. This catalogue contains 16,784 images. When you click on the image, you also get an explanation for the photo.

You can also view photos by Themes where the photos are grouped by process such as volcanic action, aeolian (wind), and fluvial (water) forms.

HiRISE is aboard the Mars Reconnaissance Orbiter that was launched in 2005. According to NASA,

“After a seven-month cruise to Mars and six months of aerobraking to reach its science orbit, Mars Reconnaissance Orbiter began seeking out the history of water on Mars with its science instruments. The instruments zoom in for extreme close-up photography of the martian surface, analyze minerals, look for subsurface water, trace how much dust and water are distributed in the atmosphere, and monitor daily global weather.

These studies are identifying deposits of minerals that may have formed in water over long periods of time, looking for evidence of shorelines of ancient seas and lakes, and analyzing deposits placed in layers over time by flowing water. The mission is examining whether underground martian ice discovered by the Mars Odyssey orbiter is the top layer of a deep ice deposit or a shallow layer in equilibrium with the atmosphere and its seasonal cycle of water vapor.”