The Greenhouse Effect Explained
91At the Heart of the Controversy - What is the Greenhouse Effect, and is it scientifically proven?
By Chef Jeff
There is much talk about the greenhouse effect, greenhouse gasses, and global warming/global climate change. I wanted to take a moment to explain as best I can what the greenhouse effect is, and how it has been seen to work on planet Earth.
The term greenhouse effect comes from the way a greenhouse is warmed internally by sunlight. Sunlight enters our atmosphere in the form of solar radiation, which passes easily through the greenhouse gasses in our atmosphere, much as in the analogy of how sunlight passes through the glass panes of the greenhouse.
The solar radiation warms the Earth's surface, just as direct sunlight will warm your skin or metal objects left out in the sunlight. If you walk down any city street just before sundown you can still often feel the effects of this solar warming coming from the sides of buildings that have been exposed to sunlight shortly before.
Now that the solar energy has been converted into heat, which is a different type of energy, it rises, as we all know heat is prone to do. Energy in the atmosphere, especially heat energy, is often responsible for those late-afternoon storms that seem to rise out of nowhere. It is also easily barred from exiting the earth's atmosphere by what are known as greenhouse gasses.
Scientific studies show that if we had no greenhouse effect, the Earth's average temperatures would be much colder than they are today. How much colder? Scientists postulate that our atmosphere would be about 33 degree Celsius colder, which is of course lower than the freezing point.
So the greenhouse effect is a well-developed hypothesis used rather commonly in science to study our planet and the climate systems we experience. But are there other factors that affect the climate? The simple answer is, yes, there are.
Volcanoes change climate
Just about 200 years ago, in 1815 and 1816, the Mount Tambora volcano on Sumbawa Island in Indonesia(1) began spewing volcanic ash. While the heavier ash settled within a few weeks, the fine ash went into the atmosphere and formed a layer in the stratosphere, about 10- 30 km (33-100,000 feet) above the surface of the Earth. Once there this fine ash effectively blocked solar radiation form reaching the Earth's surface. By 1816 the effect of this sudden cooling were felt as far away as New England, where it periodically snowed in June, 1816, and where crops were ruined because of the cold and lack of sunlight. The effect in North America lasted about three months.
In London, England, sunsets were colored purple and in Wales, Ireland and even Germany snow and frost were reported lasting into the summer months. A terrible famine occurred, which has been called the worst famine of the century(2).
So it is well documented that unexpected occurrences can and do have global effects on climate, what are sometimes called sudden changes, or blips, that occur during the cycles we otherwise often see in general climate. The Mount Tambora eruption was one type of sudden change, a temporary global cooling. As soon as the fine ash was eliminated from the atmosphere, in the form of precipitation, the regular greenhouse effect returned as before.
Mount Tambora
There have been other temporary or sudden changes in our global climate as well, such as The Little Climactic Optimum, which occurred in between 900 and 1,200 AD. During that time settlers went from Nordic lands to Greenland, which had a much milder climate at the time. They began settlements and lived much as they had in their relatively warmer home climates.
Then around 1,200 the climate returned to normal, and things got very harsh in Greenland, and what we see there today are the ruins of what had for a short time been a thriving settlement.
From 1550 to 1850 a period of unusually cooling had been seen and is called The Little Ice Age. Notice that the Mount Tambora eruption occurred within this time frame.
Now most of these events occurred in the Northern Hemispheres, and scientists are not certain that the effects were indeed truly global. They may not have affected the Southern Hemisphere quite as drastically as they did other areas. The data for this is still being discovered and examined.
From the period of about 1880 to the present day, however, the global temperatures have risen 1o C.
Hypothesis #1 - Non Anthropological Causes
I will refer to this as Hypothesis #1, which is a non-anthropological explanation for climate changes.
Scientific data has determined that in 2005 the world was indeed warmer than it had been a few decades previously. Was this a naturally occurring temperature fluctuation, or has Man managed to change the climate?
We can only determine an answer to that by studying all the things that could possibly be happening in the global climate. Some of the people who do not believe that human beings have had an effect on the atmosphere, and thus any global climate change is part of the naturally occurring cycles that come and go throughout history, have determined the data points to this conclusion: Any climate change is not affected by the habits and actions of humans, animals and greenhouse gasses. A brilliant argument in favor of non-anthropological causes for climate change can be found at another hub:
Others follow the data toward the conclusion that human and animal activities have indeed increased the global temperatures, and therefore have brought about a sudden and unexpected change in our climate. These people believe the Greenhouse Effect Hypothesis is the correct way to view this problem.
Naturally, there are many conflicts between these two views of what is happening to our climate. And also, naturally, there are other ideas in play, such as there is no change, and I will not be addressing these other viewpoints in this hub.
Hypothesis # 2 Human-Created Effects Cause Global warming
I found a very good website below that helps explain the views of those who believe mankind plays a direct part in climate change, which I shall refer to from now on as Hypothesis #2.
http://climate.nasa.gov/causes/
This site basically explains how greenhouse gasses work and why they are believed to have affected our climate. The basic premise is that as carbon dioxide levels increase in the atmosphere, the amount of heat radiation escaping into outer space from the Earth's surface has decreased. With less heat getting out, more heat is remaining in the atmosphere, and thus the climate warms.
An analogy would be as when you leave you car windows closed on a hot summer day, the interior of the car gets warmer than if you leave the windows open, and some of the heat the heat can escape. Not all of it does, but most of it will.
Anyone who has touched a hot steering wheel in a car as described above knows the power of solar radiation. There are many reasons, proponents of the greenhouse gas hypothesis claim, for the rise in both the inability of the warmth to escape, as well as the changing of the earth's surface in such a way that the amount of solar heat actually converted to heat has also risen.
Trees absorb sunlight and change the solar radiation into food, though the process of photosynthesis. Conversion in this manner reduces atmospheric warming because the energy is directed into making food instead of heat. Thus, when the earth has a lot of green growth in the form of plants, the amount of solar radiation converted to heat is less.
Is the world actually getting warmer?
What About the Forests?
So, is the Earth more or less green than before? Are there indeed less plants out there to absorb heat? Or, as some proponents of first hypothesis say, are there actually more plants on the surface than before? This argument is key for two reasons: first, plants absorb both atmospheric carbon dioxide and second, they create breathable oxygen.
Fact or fiction: Is there more forest in the United States now than when the nation was first created?
According to researchers (Bryant, et al. 1997)(3) at the World Resources Institute, there were in 1997 about 20% less forests now in North America than there were 200 years ago. Looking at places like Ohio and states east on the Eastern seaboard, that is quite visible. Whole tracts of lands explored and found to be thick forests are now towns and cities and farmland.
If this is true, then we are missing some of that 20% due to human habitation, while farmlands may indeed replace trees that were once growing on that land. Is it a balanced trade-off, though?
If the North American forests are actually growing, as reported by a United Nations report in 2001(4), then where are the new forests being planted? I went to the website forestinformation.com which is mentioned in a prominent report as being created "To celebrate the good news and educate people on North America's forests." Apparently it no longer exists as I could not find it, although it is mentioned in other web sources. (http://www.eberlpr.com/forestinformation)
However, as far as I can determine, this report covers a significantly less period of time than the past 200 years, so I remain unable to adequately answer this basic question: Are there more forests in North America today than there were 200 years ago?
Forests are called the "Lungs of our Planet." What role do they play in the balance of greenhouse gasses?
So, in the end, what does it all mean?
Science has long hypothesized that there is a balance of nature, and this idea has entered into the common vernacular. When we speak of a balance of nature, we generally believe it to mean that things as they are right now have always been this way. However, climate scientists have long held that changes are more natural than stasis, the condition in which things either don't change, or change extremely slowly.
Knowing that our world is seldom in stasis, are humans having a deleterious effect on the climate and other aspects of the world we know today. We can see locally that we have an effect on our microenvironment, building parking lots and strip malls may cause many unexpected changes, filling in wetlands increase the danger of flooding, ignoring nature, such as building a town right at the river's edge, can lead to local disaster. Nature teaches us these lessons every year.
I would say that purely on an anecdotal basis, we can see the ill-effects of poorly thought out interaction between humans and the world around us.
On a larger scale, does the creation of extra gigatons of carbon dioxide, along with methane emissions, excess atmospheric water and fluorocarbons, change the atmosphere? If one large volcano can make a sudden and unexpected change in the climate, who can safely deny that the extra carbon emissions do not produce profound and possibly longer-lasting effects?
Science has already proven the idea of the actions of a Greenhouse Effect beyond all reasonable doubt have kept a more or less stable range of temperatures for several thousands of year. And science now asks - since we know we are indeed dumping a lot of pollution into the air, and accounting for all the natural causes of extra-greenhouse gas overload, such as warming tundra, depleted rainforests, warming oceans and many other causes, does it not stand to reason that the data which points to human intervention having an effect on climate?
Last of all I leave you with the fact that the carbon molecules we are using to drive our cars were buried for millions of years beneath the soil, out of circulation, as it were. It is a fact that they come from a time when scientists are very certain that the amount of carbon in the atmosphere was much higher than it is now, and when temperatures were also much higher than they are now, and that the greenhouse effect made the Earth a much different and much less Human-friendly place than it is today.
Are we a major part of this climate change? I believe we are.
But even if I am wrong, and human beings are NOT the cause of this effect, that doesn't change much, in my opinion. If climate change at all is a reality, then it would be wise to prepare for it. Whether you believe we will be entering a cold or hot age, the reality is that many of the effects are being felt right now.
References
1: http://ppg.sagepub.com/cgi/content/abstract/27/2/230
2: Oppenheimer, Clive (2003). "Climatic, environmental and human consequences of the largest known historic eruption: Tambora volcano (Indonesia) 1815". Progress in Physical Geography 27 (2): 230-259.
3: Bryant, D., D. Nielsen, and L. Tangley. 1997. "The Last Frontier Forests: Ecosystems and Economies on the Edge." 42. Washington, DC : World Resources Institute.
4: United Nations Reports North American Forests Are Growing, found on Bnet at: http://findarticles.com/p/articles/mi_pwwi/is_200106/ai_mark01027960/pg_1
- Carbon-Water Cycle Interaction in Far Eastern
Large Carbon Sinks such as the Tundra will give off more Carbon Dioxide as they warm. Some believe this is already a huge source of carbon emmissions that is not being taken into considereation.
- More Info on Tundra Carbon Sinks.
Potential CO,-production in aerobic conditions from a Siberian tundra environment
CommentsLoading...
Great hub, Chef. Very well researched.
Dutch, from what I've learned about volcanoes, they account for only about 3% of the chlorine in the stratosphere. They aren't directly harmful to the ozone.
CJ, excellent hub. I follow most of your ideas here. The problem is that even though we may be a cause of climate change, how much can we actually rectify given the current economic climate (no pun intended). As a global community we would have to reverse 100s of years of "progress" in a relatively short time; which is probably a bit unrealistic. This does not mean we have to continue status quo. Your argument is gaining ground. Nice work.
A very very good article Mr.Chef.Highly educative. Result of good reference work and geo-concern.I wish you publish this in a news paper also.
And, I can boldly say, here you you won't get so many readers as a celebrity hubber gets!
Things will come to a balance whether they are left alone or not. The power of nature is as immeasurable as it is indifferent. Eventually what we have wrought will be the source of our own destruction and Earth will never notice.
Volcanoes can affect the climate a lot. Usually, the effects don't last more than 2 centuries at best (with current data and past eruptions). Usually though, you need a good amount of fine ash to be ejected from the volcano to cause a disruption, like Chef Jeff said with the ash blotting out the sky.
On the more positive side, good hub! Well researched and great data.
nice well written and informative hub
I read your blog with interest. Unfortunately, I believe that the presentation is misleading. I do not attribute any sinister motive to your blog. However, by taking jargon and mixing concepts, you confuse the questions which confront our society. The solution imposed will have profound consequences upon society. Therefore, concepts must be rigorously constrained, if they are to serve us well.
No one should doubt the ameliorating effect of the atmosphere on climate, as you sited. Earth would be uninhabitable for humankind due to climatic extremes, if there was no atmosphere; even aside from the lack of oxygen! But, to mix the effect of particulate matter from volcanoes with a gas such as carbon dioxide (CO2), or even methane, is misguided if not dishonest. There is no question that particulate matter, in GREAT quantity [thousands of gigatons] can affect change. The question is whether a change in CO2 wastes from 0.024 to 0.038 atmospheric composition over 150 years can be the cause of climatic change. The answer may lead to regulations deciding whether mankind should exhaust 7 gigatons of carbon waste or only 6.8 gigatons out of the total 100 gigatons of carbon waste deposited in the atmosphere each year. Even this relatively slight decrease in emissions will have a profound effect on our society and the comfort of its people, as it will reflect a 20 to 30% change in the amount of carbon used as energy in America. Its affect on the economy will be in the trillions of dollars, greater then even our current economic crisis. The anthropogenic proponents refuse to consider the 90+% of carbon wastes deposited annually by NATURE that cannot be controlled by legislation.
Conceptually, 'greenhouse' is a misnomer for the thermal effect. A greenhouse connotes a thin, rigid layer, which does not exist in the atmosphere. Conceptually, the atmosphere acts more as a thermal blanket, composed of 75% to 85% water vapor acting in concert with the oceans to provide a thermal buffer. Proponents of anthropogenic global climate change have co-opted the greenhouse term to suggest a layering of carbon waste which causes an increased reflection of thermal energy. This does NOT occur. Since CO2 is distributed throughout the atmosphere, rather than accumulating in a discrete level, the purported back scattering of thermal energy is going to occur in all directions. And, while this may, conceptually, increase the temporal insulating properties of the thermal blanket, the effect is going to be limited due to the percentage composition of the blanket. Atmospheric carbon change is more analogous to adding a layer of tissue paper to a third blanket on a cold night. The effect is going to be minimal compared to the three blankets. So it is with the 0.024 to 0.038 change in CO2 composition over the past one and a half centuries, compared to the 85% water vapor composition.
You speak of the change in temperature over the last hundred years and even allude to a millennia of climatic activity. Unfortunately, this is a trivial time frame compared to the information gleaned from ice-core data which demonstrate cyclical climate change on the order of hundreds of millennia within thousands of millennia of data. Your hundred year one degree temperature increase is easily trumped by the 12 million year 10 degree temperature DECREASE. A continuing 12 million year trend that shows many one degree fluctuations over its course.
Yes, you are right that we must prepare for the change that is taking place. But, that preparation requires an understanding of not only the direction of change; but the degree of change that we can expect; and whether or not our activity is contributing to that change to any meaningful extent. Is the change a fully loaded dump truck traveling at 100 miles an hour or a toy car traveling at only a few feet per minute?
Probably the most important lesson that I learned in school was from the teacher who revealed, 'half of all taught is wrong. Unfortunately the teachers do not know which half is false.' The lesson is to not believe blindly in what the purported experts have to say. In matters of great importance, you should look at the primary information yourself and draw your own conclusions. Based upon review of the information available from ice-core data, I do NOT believe that there is any significant anthropogenic causation of climate change. The current cycle of climate change is clearly another cycle in the thousands of years of data. Data that also show an increase in CO2 levels consistent with past cycles. CO2 increases which follow rather than preceding the temperature increases, indicating that the temperature change causes the change in CO2 and methane, not that CO2 causes temperature change. Nothing new or startling to our times.
Review the work at Vostok and others that have generated the ice-core data. For review, require temperature, CO2 and ice thickness data covering at least 400,000 years. You will see that the climate is not going to change dramatically over the next few hundred years, absent a volcanic eruption or meteor crash. Need I point out that humans can do nothing to control volcanic eruption (and very little to control meteors)? At that point, you can draw conclusions as to the course of action that your wish to take. But, please don't succumb to the hysteria of the moment (or even of a century).
Nice Hub, Jeff.
The problem, as hinted by ipsism, is that there is so much bad science out there, from BOTH sides of the debate. There is no doubt that the atmosphere is warming; it is the man-made effects that are open to debate. Sadly, politicians and the media are using the debate as a political football, and clouding the truth.
I am probably 70:30 that the effects of anthropogenic carbon emission are having an effect, and I am a great believer in erring upon the side of caution. This is an area where making a mistake could be a problem. Good research is extremely difficult to find, and even that is inconclusive. Nobody knows anything, but everybody thinks that they do!
Personally, I believe that it makes sense to wean ourselves off fossil fuels, economically and politically. Global Warming is only one possible good reason for doing this. I do not trust any research funded by oil barons, but I do not believe the likes of Al Gore, either.
To paraphrase the IPCC description of the atmospheric greenhouse effect:
1. A warm body (the earth) radiates heat to a cool body (the atmosphere)2. The cool body "back-radiates" (IPCC term) heat to the warm body.3. This process continues perpetually, with heat flowing round in a continuous cycle.4. The result of this perpetual process is that the warm body becomes warmer.
Gerlich has been published this year with a more rational view of this topic :
"Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics." G. Gerlich, R. D. TscheuschnerInternational Journal of Modern Physics B, Vol. 23, No. 3 (30 January 2009), 275-364
Hi, Jeff--
Enjoyed your hub, and would like to link to it, if that is OK with you. I've just put up the first of (I hope!) a series on the history of climate science, "The Science Of Global Warming In The Age Of Napoleon." It's kind of a "life, times & work" piece on the famous mathmatician, Fourier.
Reacting to some of the previous comments here, you are right that CO2 does become excited by solar radiation, as I understand it.
The most persuasive fact that I know of in evaluating whether or not the CO2 "blanket" is effective in heating the earth is the fact that the stratosphere has been *cooling* for thirty years now, even as lower layers of the atmosphere have been exhibiting the opposite trend. This is difficult if not impossible to explain if solar influences are somehow driving the warming trend we have observed.
Lastly, let me mention a point that has been pointed out many times but bears repeating. The fact that, in "natural" circumstances, CO2 increases follow temperature increases says nothing about our situation today. After all, we know by simply counting what we burn that we are responsible--actually, more than responsible--for the observed atmospheric increase in CO2.
In the past, that "natural" increase served to amplify the warming already started. Now, it can kick-start the whole process--"our" CO2 causes warming, which releases more CO2, which causes more warming and so on. A few decades of this, and you've got a planet 6 degrees warmer, and a host of headaches for humanity.
You are welcome, Chef!
I'll put the link in.
I don't know whether you saw this study:
Hello, once again, Chef!
A thoughtful reply. Mostly, I just dropped by to let you know that I've added another link to this hub--this time, to my new GW Historical Science Hub. (Actually, I haven't quite published it yet, though that should be minutes away.)
Let me know if for some reason you'd prefer I not link, and I'll remove the link. You can see the page at:
The-Science-of-Global-Warming
-in-the-age-of-Napoleon-III
(Paste link segments together, or search the site.)
Thanks, Chef!
Done.
The "news of the day" in the global warming blogosphere is perhaps the debate--or perhaps "speculation" is a better word--over Arctic ice melt. Everyone acknowledges that sea ice extent in the Antarctic is increasing as of now--some of the climate models predicted this, by the way--but there has been a lot of fuss about the Northern Hemisphere.
As I think you know, there had been three consecutive years of record-low extent that really shocked scientific observers. Last year broke that streak, as it was not quite as low as 2007, though still extremely low by the standards of the satellite record. Some were proclaiming a recovery this winter, as the total extent approached the norm once again; others cautioned that the ice remained very thin and vulnerable.
Yesterday, the extent dipped below the 2007 trend line, according to the National Snow and Ice Data Center site, so it seems at this point that the hopes of a real recovery of the Arctic ice pack were premature. Of course, there is really no predicting what happens for the rest of the melt season, as this is in the realm of weather, not climate, and though it may seem counterintuitive, the latter is much more predictable. Will we see a new record low, or can we hope that the ice recovers somewhat at least?
Only time will tell. But a lot of people will be watching to see what happens, and whichever way it turns out, it's safe to predict that some incautious conclusions will be drawn.
Chef Jeff - CO2 is affecting our planet and in a host of ways. Climate change may only be one of its detrimental effects.
I recently read a book called Sea Sick by Alanna Mitchell. It's an excellent resource for more of the most current science on CO2. She also does an amazing job of tying the pieces together on the overall problem of human pollution (of which CO2 is one of the biggest emissions) and how we are changing not only weather but global ocean chemistry.
I have a hub on her book - http://hubpages.com/hub/Sick-Seas-How-Alannah-Mitc - but I highly recommend reading the book itself. While a book detailing dire conditions, it is also a book of hope.
I also have a hub on carbon sequestering - which could be our best solution for all the CO2 that we have released from our planet's long term carbon stores (in fossil fuels). Check it out at: http://hubpages.com/hub/Capturing-Carbon-Is-Carbon
Thanks for covering this aspect of how humans are affecting our planet.
Great hub you've put together here, really informative, we should all be more aware of the greenhouse effect in my opinion and make changes to help reduce the impact. Thanks http://www.PlasticGreenhouseSite.com
Nice info ,Thanks for the info
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dutch84 4 years ago
Interesting.
So, do volcanos affect the Ozone layer?