Hello,
Well, use of computers certainly contributes to an increase of energy usage, therefore greenhouse gas emissions and global warming.
The very fact that computer manufacturers exist mean that the environment is impacted in some way, since manufacturers use energy and raw materials in the production process. Not forgetting of course one significant environmental factor, which is the environmental impact caused by the transportation of goods.
The use of packaging also has an impact on the environment.
Many computer components are made using substances which can harm the environment, and so they must be properly disposed of when they reach the end of their life. In reality, many consumers simply throw out computer hardware in the trash, without considering the effect it will have on the environment. Recycling electronic equipment can help protect the environment. Interestingly, recyclers generate over £100 million ($198 million) of materials from electronics every year.
Having said this, computers are becoming more energy efficient, and more conservative on energy usage.