May 2016 - The city of Rome itself has tremendous environmental advantages, which made it easier for Rome to become an important city. Rome is located at the first place that people can easily cross the Tiber river, so it is the natural location of the main north-south road in Italy. The reason you can cross the Tiber at Rome is that there is an island in the river there (this is the same as at Paris).
There are also big salt flats near the city, and because salt was so valuable in the ancient world for preserving meat and fish, selling the salt made Romans rich. Also the riverboats going up and down the Tiber, from east to west and back again, could stop at Rome.
As the Romans expanded their empire, they encountered many different environments. There were deserts, mountains, wetlands, forests, and everything else. The great variety of environments helped the Romans get lots of different food and materials. They could get tin from England, and wood from Germany, and cotton from Egypt, and silver from Spain.
The Romans also had the advantage of a good climate. During most of the time of the Roman Empire, Europe and the Mediterranean were unusually warm, about as warm as they are right now. That weather seems to have been good for Roman farming. The Romans brought Mediterranean crops like wine grapes and olives much further north than they normally grew.
But during the 200s AD, the weather got cooler. The cooler weather forced wine and olive growers to move south. It may even have made it harder to grow wheat and barley, and made it harder to heat houses in the north. This may have helped cause problems for the Romans, with both the Germans and the Sassanians invading them, and many people revolting inside the Empire as well. The fall of Rome in the 400s AD may also be related to this cooler climate, which lasted into the Early Middle Ages, until the 600s AD.
Learn by doing: talk to older people about how your local climate has changed
More about African weather
The Medieval Warming period
"European summer temperatures since Roman times", IOP Publishing (2016)
The Ancient Mediterranean World: From the Stone Age to A.D. 600, by Robin Winks and Susan Mattern-Parkes (2004).
The Corrupting Sea: A Study of Mediterranean History, by Peregrin Horden and Nicholas Purcell (2000). Hard to read, but some interesting observations about the different micro-climates of the Mediterranean and their effects on history.
The Mediterranean and the Mediterranean World in the Age of Philip II, by Fernand Braudel (1949, reprinted 1996). A classic - one of the first attempts to look at history in environmental terms.
Environment and Society in Roman North Africa: Studies in History and Archaeology, by Brent D. Shaw (1995). A collection of articles about the relationship between water and power in North Africa under Roman rule. By a specialist, for specialists, but an important book.