If you look at the surface of a pot full of water at room temperature, the surface will be smooth. If you heat it, you will see little waves and undulations on the surface. Those will become more frantic as the temperature rises. When it breaks into a boil, it will change to have bubbles and splashes and roiling waves.
When you co2 collects heat in the atmosphere, it changes. As a gas, it changes the way it absorbs and releases moisture, mostly in the direction of absorbing more. However, the more that it absorbs, the more the water wants to fall out as rain. When the air cools, because of nightfall, seasons, geographic features, some falls out.
Places where the air was being extra absorbent will have extra drought. Places where the air cools, will have extra rain. Places in-between will have in-between weather but, since the world is heating up, there will be fewer of them.
You can't predict the exact pattern of splashes and bubbles on the surface of the pot of water when it crosses the threshold into boiling. You only know it's going to be intensely agitated. As our atmosphere crosses the threshold of absorption, we don't get to know exactly what will happen, only that it's going to be a lot different and more intense.