The Greenhouse effect is what enables a livable climate on earth. In pre-industrial times, the ability of the earth to regulate itself within a climate range at different times allowed for many different climate regimes.
For the last million years, the climate has been relatively stable between warm periods and ice ages. This is due to the effect of orbital forcing in our solar system and changes in the angle of the earths tilt toward and away from the sun. These changes combined with greenhouse gases in our atmosphere and the dynamic interactions with our land, oceans and ice are what define the natural climate cycles on earth.
While there is a natural greenhouse effect, mankind during the industrial age has increased the concentration of greenhouse gases in our atmosphere. This is impacting our climate due to increases in radiative forcing. This in turn effects regional climates and causes climate change. In other words, our recent increase in greenhouse gases due to industrial output is causing global warming and global warming is causing climate change.