The amount of junk surrounding the Earth is increasing. Do you think this contributes to climate change?
No. First, there is not enough up there to impact the amount of solar energy coming into the top of the atmosphere. Space junk is very small and space is very big. [There are 300,000 pieces larger than 1 cm estimated to exist below 2,000 kilometres (1,200 mi).](https://en.wikipedia.org/wiki/Space_debris) Adding that up into a single sheet would be 3000 square meters, which at 500 miles up would be about 1.25 arc minutes wide. This is about the size of a small planetary nebula in the night sky, or about the size of the crater Copernicus on the moon. Translation, you would see it, but barely as a fuzzy source of light at the limit of normal human eyesight, about as bright as the space station on a favorable pass. This is assuming that the debris formed a sheet 1cm thick and was uniformly flat and tangent to the earth's surface. More info about space debris here. The bigger impact is aerosol levels in the upper atmosphere.These reflect light back into space. One of the factors commonly "blamed" on the sharp rise in global temps over the last 30 years is the reduction in aerosol pollutants in the upper atmosphere. But! Aerosols cause clouds as well, and clouds trap heat. When you add the two, they nearly balance out. One group was suggesting dumping a bunch of bright pollutants into the stratosphere to cool the globe, but hopefully we stop and think before we go crazy and mess with the whole planet's ecology.
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.