In 1763, Franklin took part in discussions with colonial scholars about the effects of deforestation on local climate. As forests were cleared for farming in the early American colonies, Franklin agreed with the other colonials that "cleared land absorbs more heat and melts snow quicker." However, he thought that many years of observations were necessary before any conclusive evidence could be gathered on the effects of deforestation on the local climate.

Gulf StreamIn addition to his meteorological prowess, Franklin also published the first scientific chart of the North Atlantic’s Gulf Stream. He hypothesized that the trade winds cause the Gulf Stream by driving warm waters into the Gulf of Mexico, from where they exit by way of the Florida Strait and proceed to form the Gulf Stream. In 1775, on his way to England, Franklin lowered a thermometer into the Atlantic and found the Gulf Stream to be 6° F warmer than the surrounding sea and, subsequently, produced the first chart of the current.

In the last years of his life, Franklin conducted studies on the effects that volcanic eruptions might have on weather patterns, cloud formation, and cloud electrification. He hypothesized that the severe Northern Hemisphere winter of 1783–84 was linked to the volcanic eruption occurring in Iceland in the summer of 1783. Franklin suggested that there was a reduction in the amount of solar energy received at the Earth's surface after the volcanic eruption due to the ash and other particles inserted into the atmosphere.

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On the Shoulders of Giants
Benjamin Franklin
Franklin's Climate Studies
Links and References

A sea surface temperature map of the Gulf Stream. The warm waters of the Gulf Stream (orange and red) emerge from the Gulf of Mexico, flow up the U.S. Atlantic coast, and eventually turn east towards Europe while they slowly cool. The surrounding ocean is as much as 6 degrees Fahrenheit cooler (blue and green) Image courtesy NASA SeaWiFS project, based on NOAA data.