As Urwumpe says, computer models aren't supposed to be proof of any scientific theory.
Not supposed to be proof by scientists. But some journalists and news articles imply that computer models are proof. Some people take it too much conclusively.
Orbiter is merely a computer model, and it too comes with limits to it's accuracy, just like climate models, but I very rarely hear of people complaining that these uncertainties somehow contradict the theory of gravity.
The theory of gravity is practically replicable for anybody, especially in case my glas of water next to my keypad should fall off my desk.
Predictions of potential future climate changes, based on our input of limited current knowledge, is just data and values with less certainty of realism. Although we try to do so, climate is not predictable, based on our limted possibilities, compared to all natural forces and influences. Weather is also not really predictable, less than ever on the long run.
It is a stone cold fact that the planet is currently experiencing rising mean temperatures.
Not each stone is cold...
I'm aware that some of our current measurements of mean temperatures show a slight rise above "average" (depends on what you measure; deep sea level temperature on the Antarctica for example, do not show a rise). I do not disagree to that. But I do not jump on the bandwagon of alarmism, just because some of our measurements show slight increase beyond the comma or because some climatologists think one or two things about their data. Nicely colored graphics and diagrams are easy to read. People love it very much. But paper doesn't blush.
It's a stone cold fact that greenhouse gas concentrations are (globally) rising. It's a well known theory that these gases can cause localised climate change. It's a superbly validated theory that these localised changes can be extended to a global scale. The only thing we're not certain about is how much of an effect we are having. That we are having an effect is as close to a fact as you can ever get in scientific theory.
I do not disagree that the CO2 level has risen up to 380 ppm. And I'm also aware of the children's book theory "greenhouse effect" (while the term itself is rather old and not really valid to current physics). How much of an effect we are having is not known indeed. But it can possibly turn out to be less than very minor in future, but also contrariwise.
Well, let's say the next decades would not show a significant increase of mean temperature, or even a slight decrease. What would your
superbly validated theories look like? I think they would become much elastic. Six month ago, German scientists of the Max Planck Institute have calculated, based on current sea temperatures, that the global mean tempearture
may stagnate within the next ten years, followed by a warming again in 15 to 20 years. While the latest IPCC report assumes a rise of 0,2°C within the next 20 years (which already is much less than predicted in the 1990's and the early 2000's), followed by a rise.
I still have an old schoolbook (geography) from 1994, which says that the global mean tempearture has risen by 0,75°C since industrialization. Today, almost 15 years later, the value still is almost the same.
PS: I have to mention that beside my scepticism of climate predictions and knowledge regarding climate change causes and climate driving factors, I do not disagree to reduce anthropogenic "greenhouse" gas emissions, pollution, as well as deforestation and other man-made altering effects significantly.