So in the world I've been creating, I decided that the inhabited world (which is actually pretty small because of reasons) uses steam power as its main source of energy. This inhabited area is about the size of Europe or the US, and is quite populated, but it varies in population density between a Chicago-like density and a suburban density. Additionally, they've been using this power for at least a century or two.
Regardless, this entire civilization uses advanced steam technology (think 1980s US technology but only steam power) to power everything they do. What would the environmental impact of this be? I realize that it would take fossil fuels and could pollute the environment, but to what extent would this take place?
My main questions: How would it affect the weather? How would it affect wildlife? How would it affect forests and lush areas in general? Could anything survive the repercussions of heavy steam power used over that long of a period of time?
Edit: To clarify for people who are wondering, everything is powered by steam, not necessarily in a "telephones use steam for texting" sense, but for generators.