Infrared light is infrared radiation.
Infrared radiation comes to earth from the sun, passes through the atmosphere, some energy is absorbed by the earths land mass and oceans while the rest is reflected back out into space. Greenhouse gases traps part of this outgoing radiation and reflects it back to the earths surface.
The amount of light that is reflected or absorbed by a object depends on its albedo, scored on a 0 to 1 scale with 0 albedo being highly absorptive surfaces while objects with higher reflective properties score closer to 1.
For example, the albedo of fresh asphalt is 0.04, meaning it is a great absorber of infrared light. On the other end of the spectrum, highly reflective surfaces such as ocean ice and fresh snow have higher albedo values (ocean ice have albedo scores ranging from 0.5 to 0.7, while fresh snow has high albedo scores (.80-.90) making it a great reflector of infrared light.
The only trouble is that snow and ice melt when subjected to increased temperatures, and water, with a lower albedo score then ice, means it absorbs more infrared energy than it reflects. That contributes to the green house effect.
So.... melting glaciers are a bad thing.