One swedish study investigated the long-term environmental impact of a habit of reading the news for a half an hour a day, comparing printed newspapers to reading online.
Taking European averages for different environmental impact indicators, the study concluded that the environmental impact of a printed newspaper was worse, even if only from the aspect of energy consumption. Reading a newspaper online is worse when only taking into account the generation of toxins or the carbon footprint. But the overall global impact of online news is less than half if one reads it for less than 10 minutes, and it is nearly halved if one considers only the case of Sweden. One of the biggest differences is that Sweden produces much of it's electricity in hydroelectric plants and much less in nuclear plants and burning fossil fuels. The study took into account many possible sources of environmental impact but also left out others (for lack of data), such as web infrastructure (servers, routers, etc.).