Today, we are referring to the weather and not the climate. Terms that can sometimes be confused. It is often said that we cannot trust the men and women of the moment. This statement is discredited by the lines that follow. The argument begins by reminding you that weather forecasting was a key piece of information in World War II’s preparation for the Normandy landings. Based on the best measurements and calculations available at the time, the meteorologists gave headquarters a forecast that was reasonably accurate. The decade 1950-60 saw meteorologists relying on this result to predict weather for the long-term and even modify it. You can drag clouds to make it rain whenever you like.
A decade later, Edward Lorenz (1917-1908), a meteorologist with a strong mathematical background, requested to see the brand new large computer at MIT (Massachusetts Institute of Technology in Boston). He was also a teacher at MIT. He found the problem trivial compared to high-energy physicists. They gave him time. He was determined to discover the reason it was impossible to predict weather reliably for more than three days. He simplified the dynamic equations he needed to enter into the computer to reduce the complexity of his problem. He was the inventor of this dynamical dynamical system of equations, which is today known as his nonlinear, three-dimensional deterministic dynamical system. The system does not have an analytical solution. It is therefore necessary to use numerical methods, and if possible the computer. He performed several simulations, and in one of them he realized that he should start at the middle and enter by hand the results from the previous day.
The computation time passed and the variables began to drift from one another. Over time, the predictions became more divergent. He realized this unexpected result could be due to rounding the decimal numbers in the data that he had entered manually. He round to the thousandth. This is a very small fluctuation that he considered sufficient to alter the weather forecast. E. Lorenz believed that small fluctuations did not have an appreciable impact on large-scale systems like weather. His results proved otherwise. Large-scale systems can display unpredictable behavior. This does not mean it is immune to laws. Time is not more predictable if it uses the more complicated Lorenz equations instead. Don’t believe anyone who says the weather will look in a month. You must accept that winter is colder then summer.
Lorenz created the “butterfly effects” many years later. Lorenz explained it by saying, “The flapping wings of a butterfly in Brazil can cause tornadoes in Texas.” He introduced chaos in unstable systems, which is when initial conditions are slightly altered. Lorenz is the true father of the physics of Chaos, the third revolution in science that took place in the 20th Century. It is therefore unfair that Lorenz is not on the Nobel Prize recipients list. We must not forget that chaos can occur in all areas of life, including economy, population biology and thermodynamics.
