If naturally occurring greenhouse gases warm the planet up why don't manmade ones?

Question

Our planet is only habitable because of the greenhouse effect, if there were no greenouse gases it would be so cold that life would never have evolved.

So why do some people claim that human greenhouse gas emissions don't warm the planet but natural ones do.

Answer 1

The difference between naturally occurring CO2 (that created by forest fires, rot, breathing, excretion, and volcanoes) and man-made CO2 (that created by burning coal, oil, and natural gas) is that carbon for "man-made" carbon dioxide was nicely locked away under the earth until humans dug it up. It is true that humans make CO2 in other ways than burning coal. oil, and natural gas, but those other ways are a part of the
(CO2)+(Water)=(Complex Hydrocarbons)+(oxygen) cycle.
Please read on to get the meaning of that statement,

1. Green plants combine CO2 from the air, water, and sunshine energy to create complex hydrocarbons (the material from which plant cells are constructed). Oxygen is expelled into the air. To a plant oxygen is a waste product. The chemical bonds of complex hydrocarbons hold pent up energy.

2. When plant matter burns or rots, the chemical process is reversed. The energy stored in the chemical bonds is released as heat. Oxygen combines with the Carbon to create CO2. Oxygen combines with the Hydrogen to create water.

3. In the simple case, we end up back where we started. In the simple case, plants are creating new cells as fast as the old ones are burning and rotting and in the last ten thousand years (the span of civilization) the equilibrium point has been steady at about 280 parts per million of carbon dioxide in the air (0.028%). Please notice that this is a very small percentage.

4. In the not so simple case, the real world case, not all of the plant material burns or rots. Some of it gets covered up by earth and isolated from oxygen so that it cannot burn or rot. Over time (say three plus billion years), a lot of complex hydrocarbons get covered up with earth. We call these buried hydrocarbons "oil, coal, and natural gas." All of the carbon in those buried hydrocarbons was at one time in the air as CO2.

5. In the last eighty or so years, humans have been very busy unearthing those complex hydrocarbons and burning them. Speaking of oil alone, we are currently burning about 35,000 gallons per second.

6. The level of CO2 in the air has increased by 100 parts per million since 1880. It is now at 382 parts per million.

7. The average worldwide temperature is up by a little more than one degree in the last 100 years

Those are the facts. Now for the speculation.

1. The rise in CO2 by 100 parts per million is probably caused by burning coal, oil, and natural gas. This seems like a reasonable assumption. We know for certain that burning small amounts of coal, oil, and gas throws CO2 and water vapor into the air. It stands to reason that burning a whole bunch would produce a significant increase of CO2 in the air.

2. The warming trend in worldwide temperature is directly related to the increase in CO2 in the air. Maybe. We don't know what the underlying temperature trend would be without all of this burning going on.

3. We attribute 46% of the increase in the worldwide temperature to the increase in CO2, even though we know that water vapor is a much bigger factor in keeping the earth's heat from radiating into space. We ignore water vapor because we have no conceivable way to measure the level of water vapor in the atmosphere on a worldwide basis.

Do we have conclusive proof that at least 40% of the increase in worldwide temperature is directly attributable to the 100 parts per million increases in CO2? No.

Let's suppose for a moment that the Doom Sayers are right and that burning coal, oil, and natural gas is going to melt the Greenland ice sheet, and eventually the Antarctic ice sheet and raise sea levels 240 feet, is there any chance that we will be able to convince the coal, oil, and natural gas producing nations to leave their resources in the ground and find another way to make a buck? No.

So what's the upshot of this unfortunate truth? Nothing. You might as well go back to watching bad television and drinking beer. We'll give you a call when the party's over.

Answer 2

Habitable? Kind of harsh. Try "hospitable"...and even then, it would only be relative to life as we (humans) know it. Life in the oceans would have little difference other than those terrestrial life forms that evolved on land and returned to the seas.

But, I'm sure you didn't ask the question to hash out this line of semantics.

As for GTGs, I don't think it's a matter of "if" anthropogenic emissions warm the planet, it's a matter of "how much". And the high degree of certainty with which these claims are made raises a red flag that causes some skeptics to call for a more thorough investigation.

Here's what I would like to have answered:

Greenhouse effect - what is the amount of heat in number of degrees that is attributable to this effect? And not the 10 degree range that is so popularly cited. Get the range down to the number of degree change in the last 150 years. Since this predictive arm of climatology relies almost exclusively on computer modeling, you simply can't have the entire attributable temperature change dwarfed by the margin of error.

Greenhouse gases: direct in situ measurements of infrared absorption for varying amounts of major GTGs. Yes, we've done several laboratory measurements, and the truth of the matter is that we STILL don't know the percentage contribution of each gas. Sure we can try to isolate different gases and come up with a theoretical value, but that does not necessarily reflect the dynamic natural system. In the lab, they use 2.5m tubes to approximate a column of gas in the atmosphere. I don't care if they use 2.5km tubes, this is still, in my opinion at least, a very suspect approximation. You've said that you're into mountain climbing - I'm sure you've experienced first hand, the effects of varying altitude/pressure and temperature on a natural system.

I'm just not convinced that we've gone far enough with the precision of our models. I'm sure that we have the ability to do it from a computing power standpoint, but you know what they say... GIGO.

I have a lot more questions that I'd like to have answered - maybe I'll have to start asking them - particularly with respect to tabulating the total source/sinks of CO2. For example: how much CO2 is contributed by the thermohaline conveyor? What is the variability? (And no, this is not the same as the oceanic contribution which is often calculated as a simple function of temperature. CO2 concentration of the conveyor is a function of the temperatures of the subducted volumes AT THE TIME OF SUBDUCTION: this can precede the eventual release by 100s of years.)

Answer 3

That's a good question to ask the global warming non-believers. Frankly, I think the manmade ones do warm the planet, and some gases with relatively low concentrations in the atmosphere can have large effects. People have greatly increased the carbon dioxide level of the atmosphere and that seems to be having a perceptible effect on global temperatures. In addition, there are other gases such as halons and CFCs that are so effective as greenhouse gases that we must worry about them at very low concentrations.

Answer 4

Skeptics argue that the volume of greenhouse gases coming from humans are too insignificant to have a global impact on climate change when compared to natural factors such as forest fires, volcanos, etc.
To me, the most convincing point that some of them make is that global warming and cooling cycles have been going on as long as planet Earth has been around -- even before the Industrial Revolution. They also entertain a theory that the natural warming cycle (that's been happening as usual) is releasing exponential amounts of methane that used to be trapped underneath glaciers and ice far exceeds the amount of greenhouse gases directly caused by humans.

There is still so much research and discovery that needs to be done, I'm still neutral about it.

Answer 5

First of all, 'greenhouse gases' is a term invented by the environmental wacko's that are bent on saving the planet earth. Oh I suppose with all the crap we're putting into the atmosphere, there may be a 'greenhouse' effect. Global warming is a 20th century theory that has yet to be proven. Furhermore, man-made greenhouses are closed systems, having no impact on the earth's atmosphere.

Answer 6

Well I think their argument is not that human greenhouse gas emissions don't warm the planet, but that they don't warm the planet by a significant amount. In other words, that the human contribution is overwhelmed by natural contributions.

Unfortunately for them, climate scientists have determined otherwise.

Answer 7

The point is we are blaming Co2 and human Co2 is very a small percentage of the greenhouse gases.

Earth is going through a natural cycle.
By the way, Greenland was warmer in the past,
7/6/07 http://www.knowingtruth.com/

Answer 8

Life didn't evolve, that where you missed the boat. The Same God that put you here put everything else in to motion. If you would just accept the truth you would not be so confused by the nonsense of global warming, evolution, the tooth-fairy and so on. "The Truth will Set You Free."

Answer 9

Not sure exactly what you mean by "human greenhouse gas emissions". Any sources for these claims?

I can guess that you are talking about the CO2 that humans exhale. Although this CO2 is the same greenhouse gas emitted from your car or a coal power plant, the amount that all humans breath out is only about 0.2% of the amount emitted from burning fossil fuels globally in a year. In other words, the relative contribution of this particular "human greenhouse gas" is not very significant.

See my previous post for the calculation.

Answer 10

man-made ones do.

some people dispute this because they do not want to face the horrid truth that the world faces today. They feel that if they can make themselves and others believe the facts are wrong, they won't have to worry.