|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.
In addition to his meteorological prowess, Franklin also published the first scientific chart of the North Atlantics 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 178384 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.