The greenhouse effect is when a specific type of gas, greenhouse gases, traps heat in the atmosphere. The core of climate change is that humans are emitting more greenhouse gases, while unnaturally multiplying the greenhouse effect. From there, we can draw a clear line: more heat-trapping gases mean more heat.
Rising temperatures cause all of the effects listed on this page. That's because just a couple of degrees-higher temperature throws off the earth's balance. The Intergovernmental Panel on Climate Change concluded that even just 1ºC of warming would lead to devastating and irrevocable effects.