[ckarmann]

Basic models with albedo and heat generated by the core shows that the Earth should be much colder than it is now. The greenhouse effect is studied since the 19th century and explain why the planet is not at freezing temperature all year round. That's pretty solid science and is also validated by studies of other planets.

The remaining parts are: (1) Do humans induces a rise of the amount of CO2 in the atmosphere? and (2) is the rising level of CO2 in the atmosphere provoking a rise in temperature on global scale?

It's my understanding that (1) is a simple yes: just do an accounting of the number of carbon atoms, and you realize that getting atoms of carbons out of the rocks to the surface of the planet at industrial scale means that there must be more carbons either in natural carbon storage (forests, oceans) or in the atmosphere. Since forests are not growing and the absorption of CO2 by the oceans does not seem to be very efficient, it means humans are increasing level of CO2 above themselves. Carbon doesn't magically disappear. It has to be somewhere.

(2) is the one that get difficult. There are a lot of arguments for (a lot of data points to rise both in CO2 and temperatures, a lot of models show the same thing) but all of this is modeling and correlation when what we are doing in extrapolation: is the relationship between CO2 and temperature going to stay the same as it is, or does some counter-effect going to kick in and make things smoother, or on the contrary, some effect on the atmosphere will accelerate global warming? Until we have a perfect model of the atmosphere or until we have actually got there and realize we have screwed up things or not, we can not say we have a scientific proof, and we can't be sure at which speed it's gonna happen.

But the amount of circumstantial evidence is so overwhelming and there is so much at stake that in my opinion it is not reasonable to act like it's not happening or like you need hard mathematical proof to consider it a reality.

[acqq]

The scientists calculated the contribution of other causes, not only of CO2, and here is how it compares to CO2:

https://www.bloomberg.com/graphics/2015-whats-warming-the-wo...