From WikiPedia:
"The greenhouse effect is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without its atmosphere."
"If a planet's atmosphere contains radiatively active gases
(i.e., greenhouse gases) they will radiate energy in all directions."
"Part of this radiation is directed towards the surface,
warming it."
"The intensity of the downward radiation
– that is, the strength of the greenhouse effect
– will depend on the atmosphere's temperature
and on the amount of greenhouse gases
that the atmosphere contains."
"Earth receives energy from the Sun in the form of
ultraviolet, visible, and near-infrared radiation."
"Of the total amount of solar energy available at the top of the atmosphere,
about 26% is reflected to space by the atmosphere and clouds,
and 19% is absorbed by the atmosphere and clouds."
"Most of the remaining energy
is absorbed at the surface of Earth."
Note:
The “greenhouse effect” is a public relations term unrelated to how real greenhouses work. I mean the greenhouses where plants are grown. In a real greenhouse physical barriers of walls, glass, plastic trap the heat.
There are so many problems with the sad state of modern, politicized "climate science", that the misleading name "greenhouse effect" is not worth much attention!
The Big Picture:
The balance of incoming and outgoing energy at the top of the atmosphere determines Earth’s average temperature.
Greenhouses gases change that balance by reducing how much thermal energy leaves the atmosphere.
Changing the balance causes global warming or cooling.
The amount of warming or cooling
from changes in CO2 levels,
including feedbacks,
is unknown !
from changes in CO2 levels,
including feedbacks,
is unknown !
Simple, closed system lab experiments suggest, but don't prove, the real world effect of CO2 would be small and harmless -- a mere +1 degree C. increase of the average temperature over 133 to 200 years from a doubling of CO2 !
+1 degree C. in 133 years
= CO2 increases 3 ppm per year.
+ 1 degree C. in 200 years
= CO2 increases 2 ppm per year.
ppm = parts per million
+1 degree C. in 133 years
= CO2 increases 3 ppm per year.
+ 1 degree C. in 200 years
= CO2 increases 2 ppm per year.
ppm = parts per million
The warmunists were very unhappy with small and harmless effects of CO2 predicted by the lab experiments, because that wouldn't scare anyone!
So the warmunists invented a water vapor positive feedback theory out of thin air, that would allegedly triple the warming caused by CO2 alone.
After arbitrarily tripling the results of the lab experiments, the warmunists have tried to scare the world about harmless CO2, and they repeatedly tell everyone how to live (they just love to micro-manage an economy!)
Greenhouse effect physics:
(1) The Sun warms the Earth during the day
(the atmosphere allows incoming short wave
solar radiation through).
Most of the solar radiation that gets through
is absorbed by the oceans.
The oceans warm the atmosphere above them.
(2) Earth cools during the night
(but the atmosphere blocks
some of the outgoing
long wave infrared radiation)
Our planet's surface is 71% water and 29% land.
Our planet is surrounded by a "shell of air", or atmosphere.
Earth is warmed by the short wave (SW) radiation from the sun during the day.
That can be called incoming solar radiation.
About two-thirds of the incoming solar radiation gets through the atmosphere and clouds to reach the surface.
Our planet is also a ball of molten rock with a thin layer of colder rock on top.
Volcanoes, hot springs, and geothermal vents warm the oceans and the air.
That adds up to an unknown amount of heat radiating to the surface from our planet's active core.
Earth re-radiates energy received from the sun back into space, as infrared long wave (LW) radiation, to cool off at night.
That could be called outgoing thermal radiation.
The atmosphere is transparent to incoming solar radiation.
But not 100% transparent.
The atmosphere is opaque to outgoing LW infrared radiation.
But not 100% opaque.
The chart below shows that CO2 has 4 absorption bands (aka "finger frequencies") centered at about 2, 3, 5 and 15 micron wavelengths.
The 2, 3 and 5 micron wavelength bands don’t have much effect.
The 15 micron band is the largest, widest, and most important.
CO2 (and water vapor too) absorb and 'scatter' 15μm band infrared radiation -- some of the scattering (or re-radiating) is back to Earth, reducing the rate of night time cooling.
The result of greenhouse warming is warmer nights.
If nights are warmer, then the average temperature of a whole day is warmer too.
So warmer nights = global warming
( but the warmunists never tell you that ).
CO2's strongest "greenhouse effect"
is from the first 100 ppm of CO2 in the air.
Each additional +100 ppm of CO2 in the air has significantly less effect.
The CO2 greenhouse effect is said to be logarithmic.
Warmunists claim positive feedbacks triple the claimed warming effect of CO2 alone -- their scientific proof of that is "because we say so!".
Since CO2 levels on Earth were up to 20 times higher than today in the past, if there were positive feedbacks, then Earth would have had runaway warming long ago, and there would be no one alive today to read this article!
The CO2 alarmist argument collapses without the positive feedback fairy tale.
It is much more likely that the warming effect from an additional +100 ppm of CO2 in the air would be small -- perhaps too small to measure!
Most of the temperature increases from greenhouse warming will be in the coldest, driest climates, in the winter, and at night.
The greenhouse effect should warm both poles the most (however, Antarctica has not been warming).
A narrower temperature range between the poles and the tropics would cause LESS severe weather on our planet!
Science is never "settled".
Climate science is especially far from being "settled"!
There is no real science to claim that adding CO2 to the atmosphere will have more than a small, harmless “greenhouse effect”.
But there is a lot of real science to claim that adding more CO2 to the atmosphere will accelerate the growth of the "C3" green plants used for food by humans and animals.
And that's why it would be logical to keep adding CO2 to the atmosphere, until the concentration is double to triple the current level -- the concentration that greenhouse owners prefer.
Greenhouses are often "enriched" to bring the interior CO2 level to about 1,000 ppm, versus 400 ppm CO2 in the air outside the greenhouse.
Conclusion:
Why would anyone ever think that warmer nights in colder climates would be bad?
There has never been a global discussion about warmer nights.
Every historian knows, or should know, that the colder centuries from 1300 to 1800 were not liked by people at the time ... especially the really cold period of the Maunder Solar Minimum, with low solar energy and famines in the late 1600s.