All "studies" on the effect of man made CO2 on the global average temperature are only speculations.
No one knows exactly what CO2 does, and we may never know the right answers in our lifetimes.
The best that honest scientists can do is a rough estimate using worst case assumptions.
They can consider all measured warming since 1940 (but global average temperature numbers before 1979 are not very accurate), along with the rise in CO2 since 1940 (CO2 numbers are not very accurate before 1958) ... and then ASSUME a worst case that CO2, and only CO2, caused 100% of the global warming since 1940.
That worst case estimate:
A doubling of the CO2 concentration in the atmosphere causes about a +1 degree C. global warming, assuming the temperature is ONLY affected by CO2, and there is NO known feedback effect (even the direction of a possible feedback is not known).
That would be mild, harmless global warming.
Rather than doing such calculations, and calling them a "study", to get a rough worst case estimate of the effect of CO2, it would be easier to make these assumptions:
(1)
CO2 is a mild greenhouse gas in closed system lab experiments, using artificially dried air, expected to cause mild global warming in the atmosphere.
The atmosphere, however, includes the primary greenhouse gas, water vapor, which partially overlaps the greenhouse effect expected from CO2.
(2)
There has been intermittent, mild global warming in the atmosphere since the additions of man made CO2 accelerated after 1940.
(3)
Adding man made CO2 to the atmosphere probably caused some of the warming after 1940 ... but such temperature changes have happened before on our planet, without any additions of man made CO2, so the cause(s) of the global warming after 1940 (actually no warming from 1940 to 1975) is not known.
With the one exception of the Russian INM model, the so-called climate models are nothing more than nearly worthless computer games.
When back tested, they do not "predict" the 1910 to 1940 warming.
Note: I don't trust temperature numbers before 1979, especially before 1940, because of sparse global coverage. So the claimed warming could be wrong.
The computer models, when back tested, do not predict cooling from 1940 to 1975.
That cooling is gradually being "adjusted" away by government bureaucrats so the models look better!
The cooling from 1940 to 1975 is blamed on air pollution (aka aerosols) blocking sunlight, but that is nonsense, because the air pollution did not fall out of the sky in 1975, allowing a warming trend to begin.
In fact, air pollution was gradually reduced from 1975 to 2000, although it increased in many Asian cities after 2000.
Based on their performance since 1975, climate models, on average, predict double the actual global warming, excluding the Russian INM model that seems to do a good job.
Predicting double the actual warming is STRONG evidence that the warming effect of CO2, which is unknown, is being over estimated in the climate models.
Our planet existed for 4.5 billion years with no evidence that CO2 levels ever "controlled" the climate.
The claim that CO2 levels "control" the climate since 1975 is an assertion, not a proven fact, and is not even logical.
The lack of warming from 1940 to 1975, and from 2003 to mid-2015, while CO2 levels rose (especially fast from 2003 to mid-2015) shows that CO2 is NOT the sole "climate controller.
CO2 is just one variable involved in climate change.
Fortunately, adding CO2 to the atmosphere, when using modern pollution controls, is good news.
CO2 is just one variable involved in climate change.
Fortunately, adding CO2 to the atmosphere, when using modern pollution controls, is good news.
Plant growth is increases, while their fresh water requirements are reduced.
There are thousands of experiments to prove that. Not to mention the experience of greenhouse owners.
The warming since 1979, when measured more accurately with satellites, has been mainly in the northern half of the Northern Hemisphere, mainly during the coldest six months of the year, and mainly at night
Think of warmer winter nights in Siberia, Russia.
That is a great time and location for a slightly warmer climate!
Mild global warming since 1979 has been 100% good news.
There is a logical reason to claim that global warming will continue, but no logical reason to claim it will be bad news, or even a problem.
The (false) claim of a coming "existential" climate crisis appears to be an attempt to scare people into giving their government absolute power over their energy use.
That is a great time and location for a slightly warmer climate!
Mild global warming since 1979 has been 100% good news.
There is a logical reason to claim that global warming will continue, but no logical reason to claim it will be bad news, or even a problem.
The (false) claim of a coming "existential" climate crisis appears to be an attempt to scare people into giving their government absolute power over their energy use.
As if governments had not already seized enough power over our lives in 2020.
The current political goal of replacing inexpensive, reliable electric power sources, with more expensive, intermittent electric power sources, is just the type of foolish and expensive idea one would expect from politicians.
Claiming that the effect of CO2 is known, and 50 years of claiming a climate crisis is coming, is junk science.
Claiming that CO2 is probably responsible for some global warming, and observing that the global warming in the past 300 years has been beneficial, is real science.
The current political goal of replacing inexpensive, reliable electric power sources, with more expensive, intermittent electric power sources, is just the type of foolish and expensive idea one would expect from politicians.
Claiming that the effect of CO2 is known, and 50 years of claiming a climate crisis is coming, is junk science.
Claiming that CO2 is probably responsible for some global warming, and observing that the global warming in the past 300 years has been beneficial, is real science.
I'm amazed that climate alarmists believe the "pre - industrial" climate was "perfect", and any deviation from that are a "crisis".
There are almost no real time measurements of the temperature "pre - industrial" , and no real time CO2 measurements.
So the CO2 levels have to be roughly estimated from ice cores, and the temperatures are a rough estimate from climate proxies too.
Meaning the "perfect" pre-industrial climate is based on a rough estimate.
Even worse, people living in the 1650 to 1750 period did not think their climate was "perfect" -- especially people living in the late 1600's -- they thought their climate was too cold.
There are almost no real time measurements of the temperature "pre - industrial" , and no real time CO2 measurements.
So the CO2 levels have to be roughly estimated from ice cores, and the temperatures are a rough estimate from climate proxies too.
Meaning the "perfect" pre-industrial climate is based on a rough estimate.
Even worse, people living in the 1650 to 1750 period did not think their climate was "perfect" -- especially people living in the late 1600's -- they thought their climate was too cold.
They would have LOVED today's warmer climate, which is claimed to be part of a "climate crisis".
In 4.5 billion years of Earth's climate history, there are no accurate CO2 measurements before 1958, and no accurate global average temperature measurements before 1979.
Why would anyone chose "pre-industrial" as the "perfect climate"?
How about the earlier time when Greenland was warm enough for lots of farming?
In 4.5 billion years of Earth's climate history, there are no accurate CO2 measurements before 1958, and no accurate global average temperature measurements before 1979.
Why would anyone chose "pre-industrial" as the "perfect climate"?
How about the earlier time when Greenland was warm enough for lots of farming?
We don't have precise numbers, but anecdotes suggest that was much closer to a "perfect" climate.
How about today's climate? It seems very pleasant to me. Not as cold as in the 1970s here in Michigan.
The honest global warming chart, annual average absolute temperatures, for each tear from 1880 through 2016, in degrees F.
