I can only agree with the second last sentence in your comment that we should take better care of our planet. I disagree with the rest of your comment because you are mixing up causes and effects of global warming.
Where do you take evidence that "...the temperature rising and falling does drive CO2 levels..." in the atmosphere? Neither vegetation nor oceans "produce CO2". The ocean water can store some CO2, the warmer the water the lower the amount of CO2 which can be absorbed by the water, however. So heating up the water of the oceans does release some of the CO2 absorbed earlier. This is called a feedback-effect of the warming of the oceans. It should not be mixed up with the cause of warming.
The vegetation is converting CO2 into oxygen - vegetation is actually reducing the CO2 level in the atmosphere (it is doing just the opposite of what you are saying). This is one of the reasons forests are so important!
There is indeed scientific evidence that increasing the CO2 levels in the atmosphere is causing the Earth to warm up . We know how much CO2 we are releasing with burning of fossil fuels . We can measure the CO2 concentration in the atmosphere and we can compare them with CO2 levels thousands of years back using ice core samples.
You can download from timeforchange.org a spreadsheet to simulate the main cause and effects of global warming yourself. This is quite helpful to get a feeling for the magnitude of the problem we are facing. Or you can also view some simulation results of ways for mitigation of the effects of global warming .