There are many more examples in nature when something tracy makes a big difference. Planet Earth is only 3 ppm of the solar system and our atmosphere is like a tiny blanket over us. We are very tracy already. Small changes in the composition of the atmosphere can have major consequences.
How much % CO2 is of the already very tiny atmosphere is a comparison that does not mean that much. Only the greenhouse gases can capture heat radiation. The rest of the atmosphere contributes to just taking over heat from CO2, water vapor and co.
When it comes to greenhouse gases, what matters is abilities, longevity and increases.
As for the “common sense” scale argument that a very small part of something can’t have much of an effect on it, it only takes 0.1 grams of cyanide to kill an adult, which is about 0.0001% of your body weight.
Compare this with carbon dioxide, which currently makes up 0.04% of the atmosphere and is a strong greenhouse gas. Meanwhile, nitrogen makes up 78% of the atmosphere and yet is highly unreactive.
The total mass of ozone in the atmosphere is about 3 billion metric tons. That may seem like a lot, but it is only 0.00006 percent of the atmosphere.
Still, ozone protects life on Earth from the Sun’s dangerous ultraviolet (UV) radiation.
Let me guess:
When CO2 is "only plant food", C02 is everywhere, has super powers, and there are unimaginable amounts of it because it is after all the reason why all the plants and trees on Earth breathe and live. Plants, like all animals and humans, depend entirely on.
Right?
However, when CO2 is used to explain an increase in greenhouse effect, then it has suddenly become so small, so insignificant and powerless. So tiiiiiiiiny. Just a traaaaaace.
Right?
Here is the thing with C02:
- CO2 happens to have a special feature naturally. It absorbs heat radiation very effectively. It has to do with the vibratory and rotational properties of the molecule itself. The structure of their molecules makes them especially effective at absorbing heat radiation while the major atmospheric gases, nitrogen and oxygen, are essentially transparent to it. We can easily measure their properties in laboratories, and derive them from quantum physics.
- This ability to absorb and re-emit infrared energy is what makes CO2 an effective heat-trapping greenhouse gas. Not all gas molecules are able to absorb IR radiation. For example, nitrogen (N2) and oxygen (O2), which make up more than 90% of Earth's atmosphere, do not absorb infrared photons. CO2 molecules can vibrate in ways that simpler nitrogen and oxygen molecules cannot, which allows CO2 molecules to capture the IR photons.
Without CO2 and the other non-condensing greenhouse gases ability to absorb infrared radiation, the terrestrial greenhouse would collapse and throw the global climate into an ice-bound state. Without the greenhouse gases in the atmosphere, the mean temperature of the Earth would be down to -15 degrees Celsius (3 F) instead of + 15 degrees Celsius (60F).
Atmospheric CO2: Principal Control Knob Governing Earth’s Temperature
https://www.ipcc.ch/pdf/assessme...
How long do greenhouse gases stay in the air?
The ppm levels in the atmosphere does matter:
Climate deniers makes many contradicting myths about climate. Here is another:
When CO2 is "only", "plant food", C02 is everywhere, has super powers, and there are unimaginable amounts of it because it is after all the reason why all the plants and trees on Earth breathe and live. Plants, like all animals and humans, depend entirely on.
However,
when CO2 is used to explain an increase in greenhouse effect, then it has suddenly become so small, so insignificant and powerless. So tiiiiiiiiny. Just a traaaaaace.
And yes, C02 is also a pollutant. Think of it as the oceans;
The water is all good while in the oceans, but if the waters are flooding your home, it’s not good anymore.
The US supreme court ruled that carbon dioxide is a pollutant in a landmark 2007 case.
But this is the importance of C02 and the other non condensable gases:
Without CO2 and the other non-condensing greenhouse gases ability to absorb infrared radiation, the terrestrial greenhouse would collapse and throw the global climate into an ice-bound state. Without the greenhouse gases in the atmosphere, the mean temperature of the Earth would be down to -15 degrees Celsius instead of + 15 degrees Celsius.
If there had been no increase in the amounts of non-condensable greenhouse gases, the amount of water vapor in the atmosphere would not have changed with all other variables remaining the same. The addition of the non-condensable gases causes the temperature to increase and this leads to an increase in water vapor that further increases the temperature. This is an example of a positive feedback effect. The warming due to increasing non-condensable gases causes more water vapor to enter the atmosphere, which adds to the effect of the non-condensables.
https://www.bbc.com/news/science...
If our C02 is increasing, then we should see that the amount of IR leaving the planet has decreased over time, and that decrease should match the increase in CO2. That is, of course, exactly what satellite data show (Harries et al. 2001; Griggs and Harries 2007). The IR leaving the earth since the 70s has decreased, and that decrease matches the increase in CO2. This is a direct test of anthropogenic climate change and cannot be explained by anything other than our CO2 trapping heat.
https://research-information.bristol.ac.uk/files/3006745/paper.pdf
https://journals.ametsoc.org/doi...
“The earth’s climate is constrained by well-known and elementary physical principles, such as energy balance, flow, and conservation. Greenhouse gases affect the atmospheric optical depth for infrared radiation, and increased opacity implies higher altitude from which earth’s equivalent bulk heat loss takes place. Such an increase is seen in the reanalyses, and the outgoing long-wave radiation has become more diffuse over time, consistent with an increased influence of greenhouse gases on the vertical energy flow from the surface to the top of the atmosphere.”
https://link.springer.com/articl...
“We have shown that longwave downward radiation flux increases at Earth's surface can be accurately measured, subdivided and explicitly explained and backed with model calculations as cloud-, temperature-, water vapour- and enhanced greenhouse gas radiative forcing effect. Radiative forcing - measured at Earth's surface - corroborate the increasing greenhouse effect.”
http://onlinelibrary.wiley.com/d...
“The changes of the outgoing longwave radiation (OLR) in clear-sky conditions have been calculated using High Resolution Infrared Radiation Sounder (HIRS) observations from 1979 to 2004.[...] The observed increase in GHE is shown to be inconsistent with the control ensemble, indicating that anthropogenic forcings are required to reproduce the observed changes in GHE. Satellite-Based Reconstruction of the Tropical Oceanic Clear-Sky Outgoing Longwave Radiation and Comparison with Climate Models.”
http://journals.ametsoc.org/doi/...
THE GREENHOUSE EFFECT:
While other planets in Earth's solar system are either scorching hot or bitterly cold, Earth's surface has relatively mild, stable temperatures. Earth enjoys these temperatures because of its atmosphere, which is the thin layer of gases that cloak and protect the planet.
Step 1: Solar radiation reaches the Earth's atmosphere - some of this is reflected back into space.
Step 2: The rest of the sun's energy is absorbed by the land and the oceans, heating the Earth.
Step 3: Heat radiates from Earth towards space.
Step 4: Some of this heat is trapped by greenhouse gases in the
atmosphere, keeping the Earth warm enough to sustain life.
Step 5: Human activities such as burning fossil fuels, agriculture and land clearing are increasing the amount of greenhouse gases released into the atmosphere.
Step 6: This is trapping extra heat, and causing the Earth's temperature to rise
Here's what they're teaching undergrads at Stanford:
00:00 - Chapter 1. Earth Energy Balance 03:34 - Chapter 2. Black Body Radiation -- Wien's Law and Stephan-Boltzmann Law 16:05 - Chapter 3. Infrared Emission 18:08 - Chapter 4. Simple Model of Earth's Energy Balance 25:51 - Chapter 5. Equilibrium Calculations of Earth's Energy Budget 33:29 - Chapter 6. Greenhouse Effect in Earth's Atmosphere 40:39 - Chapter 7. Energy Budgets for Other Planets 45:24 - Chapter 8. What is a Greenhouse Gas?
Complete course materials are available at the Open Yale Courses website:
C02 IS A FORCING AND WATER VAPOUR IS A FEEDBACK.
Water vapor doesn't accumulate, it rains out. What's accumulating, is CO2 and Methane. Water vapor *amplifies* the CO2 effect. But it doesn't accumulate like CO2 and Methane do. so it's not itself a driver of the changes we see. The amount of water vapor in the air is a function of temperature and pressure. As temperatures go up, the air will hold slightly more vapor, and that in turn traps more heat. The amount of vapor can be calculated using the Clausius-Clapeyron equations that are taught in 1st year physics
GHGs, CO2, slow the transmission of IR energy from the surface into space by absorbing and re-emitting IR photons instead of being transparent to IR like non-GHG molecules
Direct Observation of Carbon Dioxide’s Increasing Greenhouse Effect at the Earth’s Surface
Berkeley Lab researchers link rising CO2 levels from fossil fuels to an upward trend in radiative forcing at two locations
"the critical link between c02 concentrations and the addition of energy to the system, or the greenhouse effect [...] and further confirmation that the calculations used in today’s climate models are on track when it comes to representing the impact of CO2.
Scientists have observed an increase in carbon dioxide’s greenhouse effect at the Earth’s surface for the first time. The researchers, led by scientists from the US Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), measured atmospheric carbon dioxide’s increasing capacity to absorb thermal radiation emitted from the Earth’s surface over an eleven-year period at two locations in North America. They attributed this upward trend to rising CO2 levels from fossil fuel emissions.
The influence of atmospheric CO2 on the balance between incoming energy from the Sun and outgoing heat from the Earth (also called the planet’s energy balance) is well established. But this effect has not been experimentally confirmed outside the laboratory until now.
The results agree with theoretical predictions of the greenhouse effect due to human activity. The research also provides further confirmation that the calculations used in today’s climate models are on track when it comes to representing the impact of CO2.
They found that CO2 was responsible for a significant uptick in radiative forcing at both locations, about two-tenths of a Watt per square meter per decade. They linked this trend to the 22 parts-per-million increase in atmospheric CO2 between 2000 and 2010. Much of this CO2 is from the burning of fossil fuels, according to a modeling system that tracks CO2 sources around the world.
“We see, for the first time in the field, the amplification of the greenhouse effect because there’s more CO2 in the atmosphere to absorb what the Earth emits in response to incoming solar radiation,” says Daniel Feldman, a scientist in Berkeley Lab’s Earth Sciences Division and lead author of the Nature paper.
“Numerous studies show rising atmospheric CO2 concentrations, but our study provides the critical link between those concentrations and the addition of energy to the system, or the greenhouse effect,” Feldman adds.
Roger Fjellstad Olsen's answer to How long have we known about the greenhouse effect?
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