As you know, the planet Venus is enshrouded by clouds. Venus is also very, very hot by our standards, with temperatures of many hundreds of degrees fahrenheit by the most conservative estimates. The two are not coincidental!

Have you ever noticed on a night when you are observing the stars, that the temperature tends to be cooler, than when it is cloudy? This “sealing in” of the heat, is a temporary “Greenhouse Effect”. It happens all the time. Sunlight, or shortwave radiation, comes in during the day, but in our example, is trapped by the clouds at night, so that the ground is not able to “see” the sky, and thus radiate away the daytime heat back to space as “long wave” radiation. This is exactly how a greenhouse operates.. the sunlight comes in as shortwave radiation, but the GLASS inhibits the long wave radiation from returning to space.

On Venus, the bright cloud deck of the day is able to allow just enough brightness in to warm the planet, but the clouds and gases trap in the heat on a permanent basis. On Earth, man-made gases have the same effect as the glass walls and ceiling of a greenhouse: They do not let the long-wave radiation return to space. The higher the carbon dioxide level, the more difficult it should be for the heat of the day(s) to escape out, leaving some to suggest that we will eventually follow Venus down the road to planetary doom.

It probably isn’t quite as serious as that, firstly, and obviously because we are further from the Sun. Nonetheless, the Greenhouse effect, if it came to full fruition, could be devastating to the Earth in many related ways, not directly from the warm-up itself.

The biggest quarrel in the Meteorological community of all time has to be whether or not we have already begun Greenhouse warming. You might think it would be obvious, but the problem is that there is already a swing in temperature globally from time to time that is natural. In fact, while we ARE currently as warm as the Earth has ever been to our knowledge, it has happened before, and may just be part of a normal cycle. The Greenhouse Effect will not really be able to be detected for sure until AFTER it has happened, almost by definition. That is to say, we have to look back in time to see a significant period of warming that is uncharacteristic of any normal swing in climate. If we do not know that the Greenhouse Effect is here until after the fact, then also by definition, logic implies we can’t really wait until we are sure it is here to try to stop it from getting out of hand!

A larger number of scientists and climatologists now believe that we are entering a significant “Greenhouse” warming because

a. It is already a very warm period in Earth’s climatological history

b. New, sophisticated computer models are PREDICTING a major warm up due to the excess Carbon Dioxide, of up to 8 degrees Fahrenheit in the next 30 years (globally) But of course, even the computer models disagree, some pointing to a much lower number.

What would really happen though, if there WAS a bit of a warm up, to some.. it seems almost enticing… Well, it is not so much the direct effects of a warm up, as the indirect ones. For instance, the polar ice caps would melt just enough to bring on a very significant rise in sea level… enough to flood some low lying cities around the world. (New Orleans, La., USA, as an example is already below sea level) Also, Hurricane and Typhoon frequency would undoubtably rise from the warm ocean, which helps create them in the first place. Thus, the areas that are already oceanfront, and vulnerable to sea level increases, are now also potentially threatened by Hurricanes, which could bring that seawater onshore even further, and more frequently.

Other indirect effects of a “greenhouse” warm up include climate shifting so that many species of animals and especially trees will be totally relocated, or threatened. Also, this shifting around could bring devastating areas of drought and/or heat (many predict the Midwestern United States would suffer) to established agricultural areas around the world. On the bright side, both man, and nature have adapted well to gradual climate shifts before. Even if there is an overall trend “upward” in temperature, we may have time to adjust to the change. Also, based on some predictions in the 1960s, we could have already been much warmer, globally, than it is today.

Meanwhile, Mother Nature seems to have a way of compensating for swings in climate. It is quite possible that a series of volcanic eruptions, for instance, could substantially halt a major global warming at the same time that man begins to use less fossil fuel in the future, thus putting a lid on the Greenhouse effect. (Volcanic eruptions spew particles into the Stratisphere where they are trapped for years, to the detriment of astronomers. However, this “cloud” acts to prevent incident solar radiation more than keeping the heat locked in, thus it cools the Earth. In the most extreme instance, this could cause a dramatic cooling of the Earth)

So, overall, the debate revolving around the Greenhouse controversy boils down to more of the questions such as: “how bad is Greenhouse warming?” rather than: “is Greenhouse warming for real?” My opinion is that this matter should be taken very seriously, because a cure “better late than never”, may just not be enough!

The crude idea in the common popular presentation of the greenhouse effect is that the atmosphere is transparent to sunlight apart from the very significant reflectivity of both clouds and the surface, which heats the Earth’s surface. The surface offsets that heating by radiating in the infrared. The infrared radiation increases with increasing surface temperature, and the temperature adjusts until balance is achieved. If the atmosphere were also transparent to infrared radiation, the infrared radiation produced by an average surface temperature of minus eighteen degrees centigrade would balance the incoming solar radiation (less that amount reflected back to space by clouds). The atmosphere is not transparent in the infrared, however. So the Earth must heat up somewhat more to deliver the same flux of infrared radiation to space. That is what is called the greenhouse effect.

However, the greenhouse gas/global warming issue has to do with the ramifications of the increasing levels of carbon dioxide, methane, and other man-made greenhouse gases in the atmosphere which can severely exacerbate the normal level global warming to where it presents a significant problem. In a major study of the effect of greenhouse gases on global temperatures, V. Ramanathan et al. estimate that CO2 emissions contribute to 66% of global warming over the period 1880-1980.

Water vapor is just the beginning of the issue. Clouds can either exacerbate or mitigate the greenhouse effect depending of their altitude, density, location, etc., etc. In fact, some scientists believe that water vapor could contribute to drying of the air at high altitudes and increased intensity of convection. This is an active research topic. I think that the complexities of the Earth’s biosphere plus the human element is what distinguishes the situation of Earth from that of Mars in this case. Clearly, water vapor plays a significant role, but the topic is a little more complex than that implied in your post.

Different materials may be transparent to different frequencies of light. Glass is transparent to visible light, but much less so to infrared. So the sun shines into the greenhouse, materials inside absorb the energy and become warm, then re-radiate it as infrared, which is mostly reflected back from the glass, so the greenhouse continues to warm up beyond the outdoor temperature.

“Greenhouse gases” in the atmosphere, such as CO2 and methane, have the same kind of effect, reflecting infrared back to the earth.

Btw, not all transparent materials act like glass in this regard. The possibility exists to make sheets of diamond using vapor deposition techniques. This material would be transparent to both visible and IR light, just the thing for car windows in warm climates.

1. Control and limit population growth.
2. Encourage space exploration and the colonization of the solar system.
3. Discourage the development, drilling and the consumption of oil.
4. Discourage oil-based automobiles.
5. Develop small localized mass transist solutions that can interface as nodes with other small transportation projects.
6. Restrict factory farming and livestock domestication to sustainable levels.
7. Decentralize power generation.
8. Invest in small local renewable energy solutions not large projects.
9. Invest in ecosystem-specific solutions by biosphere and region.
10. Use existing freeways and highways for mass transit solutions.
11. Heavily fund govt based greenhouse R&D by extracting funds fromthe military budget of your nation.
12. Use the knowledge obtained from greenhouse R&D to both solve the greenhouse problem at home, stabilize the climate and maintain an artificial equilibrium, and eventualy promote the development of artificial atmospheres and/or habitats to sustain life support on local solar system moons and planetoids or in orbit on artificial platforms revolving around the sun.

Please share your thoughts with us.

1. Cold areas will become tropical and extend growing seasons to feed expanding populations.

This is clearly not true. Cold areas may become warmer but they will certainly not become tropical. They will for example still have long dark winters during which nothing will grow. The growing season may be extended, at least in some areas, but this kind of regional studies are still in their infancy.

2. Increased carbon dioxide in the air has been known to promote green plant growth, which tends to consume the carbon, capture it and create lush and most areas.

This is true in a greenhouse with unlimited supply of water and nutrients, but is generally considered to be an insignificant effect in nature. To the extent there will be carbon fertilization this is not necessarily a good thing either. The extra plant mass tends to be mostly cellulose which mean that the nutrient contents of the plants go down and animals will have a harder time getting enough food.

3. The rising sea water may not be as significant as predicted. The rise is due to the expansion of water by temperature, not by the volume added by the melting ice caps.

That thermal expanson will be most important is what is predicted so how can this be less significant than predicted? The fate of the ice caps is largely unknown but adds a considerable risk.

4. Brighter sun may mean that we can use solar energy to cool our homes with environmentally clean refrigerants.

Why should the sun get brighter just because we add more CO2 to the atmosphere? If anything there is supposed to be slightly more clouds giving less sunshine.

5. Warmer climate means less fuel burned for heating our homes.

But more for cooling them. Not to mention what the expected increase in intense rainfall will do.

6. More days at the beach.

Yeah, right. That is certainly the most important problem for the majority of the population in the world right now.

“If global warming does take place and…environmental degradation follows, there will be great risks of dispute between states about food…the use of productive land…the supply of fresh water…people who are maybe fleeing from particular environmental problems,” he said.

“And all these problems could be complicated by civil war, in the same way that in Africa at the moment the problems of environmental degradation are very severely complicated by civil war,” Tickell said.

He added that the Security Council should look into the problems.

Tickell, himself a climatologist, was speaking to journalists shortly after addressing a special meeting of the Economic and Social Council (ECOSOC) on global climate change.

Tickell told ECOSOC the steady increase of so-called “greenhouse gases” — especially carbon dioxide, chlorofluorocarbons and methane — could lead to a rise in average global temperature with incalculable consequences for human society.

“This problem is comparable in its scale and complexity with that which arose from the discovery of nuclear energy more than 50 years ago.”

USEFUL FACTS:

Sources of methane: rice paddies, termites, coal mines, land fills, and digestive tracts of animals.  Estimated shares:

Tundra, bogs, swamps          26%
Rice                          20
Livestock                     15
Burning of vegetation         10
Oil and natural gas            8
Landfills                      7
Coal mining                    6
Wild animals and termites      4
Animal waste                   3
Oceans                         1

Concentration of methane in the atmosphere has more than doubled in the last 300 years, from 650 ppb (parts per billion) to 1,700, and is increasing at a rate of 1% per year.

Methane is 20-30 times as effective in trapping heat as CO2.  While its atmospheric concentration is much lower, therefore, it makes up about 20-25% of the global warming problem, while CO2 is 50-55% and another 20-25% is CFCs (chlorofluorocarbons).

Environmental Protection Agency (EPA) today [11/22/89] is publishing report on prospects for reducing methane.

Methane may be easier to control than CO2 or CFCs, because its lifetime in the atmosphere is short (~10 years).  A cut in emissions of 10-20%, the report says, would stabilize atmospheric levels.

Of that amount, 50-75% can be achieved by cutting emissions from farm animals by 50%.  Among techniques to do this: improved feed and nutrition, hormone treatments to improve productivity.

Total yearly emissions are placed at 425-675 million tons by scientists.  Of that amount, “human-induced sources” are 60%, natural 40%.

One fear: global warming may cause the release of “methane locked in frozen tundra and in permafrost in the sediments at the bottom of arctic seas…releasing vast new amounts of methane that would further promote atmospheric warming.”

• The physics of CO2 trapping heat are well understood and not a matter of disagreement.
• The CO2 content of the atmosphere has increased about 20% over the last 100 years. The global temperature has not increased in a statistically significant amount.
• The computer models that predict significant global warming over the next 50 – 100 years also predict significant global warming over that last 100 years – warming which did not occur.
• The models are unsophisticated in their treatment of clouds.
• The models do not simulate biological interactions with greenhouse warming.

From this, I would conclude:

• The greenhouse effect is far from a sure thing
• If you significantly change the content of the atmosphere’s heat trapping gases (CO2, methane, flourocarbons, etc) something ought to happen, but no one has been able to measure it yet.
• If someone tells you that the sea level will rise x feet in the next 50 years, or that the midwest will turn into a desert, don’t pay any attention – the science is nowhere near being able to predict the effects.
• The usual crowd of doomsayers and eco-politico’s have taken the effect all out of proportion – using projections from unsophisticated models as if they were gospel, while ignoring other evidence.

The earth’s atmosphere and biosphere is a very complex environment with many poorly understood but very powerful feedback loops. The changes in the earth’s atmosphere will be opposed by very powerful negative feedback, which will probably limit them – but we can’t tell if they will result in minimal change, large change, or oscillatory phenomena. There is also a possibility of triggering positive feedback which could accelerate global warming (or even cooling) as a response to these changes.

Finally, lets remember that 10 years ago the same alarmists were warning us about an impending ice age.