This is sometimes the case, sometimes not.
If you're close to MEA over mountainous terrain, quite possibly not.
The two greatest buildup conditions are either freezing rain with supercooled water droplets, or large supercooled water droplets near the -10 deg C range. A descent of 3,000' in either case may not be possible, and may not get you out of the ice; a climb likewise may do little to protect you.
The nature of the conditions determine your options. If you're in a layer and icing up, you may well simply be able to climb or descend out of the layer. Icing is commonly found greatest in relatively narrow bands...but one should never count on that. Further, even if one stops the ice buildup, one may be stuck with what's on the airframe and be unable to shed it.
Know in advance where your best prosepcts lie for escaping icing conditions. Know where the freezing level is, the extent of visible moisture or precipitation, and look over lifted indexes, pilot reports of ice, etc. This should always be a primary consideration, especially in a light airplane, remembering that your ice protection isn't there to allow you to stay in the ice, but to get you out of the ice. Plan accordingly.