Ed Lorenz uncovered a non-linear, complex, interdependent system of equations that describe the real movement of the atmosphere.
He showed that atmospheric models are so dependent on initial and boundary conditions (starting data supplied to the model) that even seemingly infinitesimal changes in them create major changes in the system. In other words, when a butterfly flaps its wings over Beijing, the models might well predict that it will change the weather in New York. But everyone admitted that just couldn’t happen.
Lorenz discovered not how to make long-range predictions, but rather the forces that make such predictions impossible. He then developed chaos theory, the study of chaotic and unpredictable systems. Scientists are discovering that many natural, biological, and environmental systems are best described and better understood under chaos theory than through traditional forms of analysis.
Having a computer was enough of a novelty in 1958 to entice many MIT faculty and students to make the trip to Ed Lorenz’s office just to watch the thing work. But excitement quickly turned to despair for Lorenz.
Lorenz created a set of equations to act as a mathematical model of atmospheric storm movement and behavior. He noticed that tiny changes in the starting conditions of the model soon produced enormous changes in the outcome. Tiny starting differences always amplified over time, rather than damping, or normalizing out.
If the actual atmosphere acted like Lorenz’s models, he had just proved that long-range weather forecasting was impossible since starting conditions were never known with enough precision to prevent chaotic, amplified error. It was an unsettling and sinking feeling to trade the excitement of finding a new research tool for the despair of proving that your field and work were both inherently flawed and impossible.
When Ed entered Dartmouth College in 1934, he had long ago made up his mind to be a mathematician. He graduated with a bachelor’s degree in mathematics in 1938 and entered Harvard to continue his study of math. With the outbreak of World War II, Lorenz joined the Army Air Corps, who assigned him to attend army meteorology classes at MIT.
He learned to regard the weather as a combination of density, pressure, temperature, three-dimensional wind velocities, and the atmosphere’s gaseous, liquid, and solid content. The equations that describe this host of variables define the current weather conditions. The rates of change in these equations define the changing weather pattern.
What Lorenz was not taught, and only much later discovered, was that no one knew how to use these nonlinear dynamic meteorology equations to actually predict weather and that most thought it could not be done. The equations were too complex and required too much initial and boundary data.
Lorenz tried to apply the dynamic equations to predict the motion of storms. As computers were not commonly available in the early 1950s, most of this work was carried out on blackboards and with slide rules and paper and pencil. Each calculation was tediously time-consuming. Lorenz was never able to reach any meaningful results while handcalculating these equations.
In 1958 Lorenz obtained that Royal-McBee LGP-30 computer (about the size of a large desk) to develop his sets of dynamic, nonlinear model equations. The results of those computer simulations showed that tiny initial differences amplified over time, rather than gradually normalizing out. If the model was right, weather was chaotic and inherently unpredictable.
Several years of atmospheric testing convinced Lorenz and others in his department that he and his model were correct. The atmosphere was a chaotic rather than a predictable system (such as the system of interactions between inorganic chemicals, or the physical pull of gravity). A drive to use a new tool to complete an old project had turned into one of the most profound discoveries for the science of meteorology.
Lorenz will always be known as the person who discovered the true nature of the atmosphere and who thereby discovered the limits of accuracy of weather forecasting.
Actor Jeff Goldblum played the role of Ian Malcolm in the Jurassic Park movies. Malcolm is a mathematician who specializes in the study of the chaos theory and refers to himself as a “chaotician.” A central theme of these movies is proving that Malcolm’s chaos theories are right.
