I'm pretty sure it doesn't. The lowest stable (many years) orbits are about as low as 400 km (like the ISS). They can be lower, but then they decrease rapidly due to atmospheric drag. The high number of objects in low orbit is still very small compared to the vast empty volume of space! The simulations showing orbital trash give a bad sense of the area covered by it... I guess less that a fraction of a percent of the total solar power is blocked by the trash. That being said, I don't know much about Earth science. The only way I can imagine the trash has an affect is when a decaying object falls to Earth. It could have an effect similar to a plane's vapor trails, maybe. Keep in mind I am not an expert of this topic, and it's so hard to predict anything in the chaotic world of climate science... If we can find a source on the topic, it would be better.