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Edward Norton Lorenz (1917–2008)

Basic Information

  • Full name: Edward Norton Lorenz
  • Born: 23 May 1917, West Hartford, Connecticut, USA
  • Died: 16 April 2008 (aged 90), Cambridge, Massachusetts, USA (cancer, at home surrounded by family)
  • Nationality: American
  • Fields: Meteorology, mathematics, chaos theory

Family Background

  • Father: Edward Henry Lorenz (1882–1956), born in Hartford; attended Hartford High School and Trinity College; majored in mechanical engineering at MIT (then in downtown Boston). Small in stature but an excellent distance runner – held the MIT record for the 2-mile run. From him, Ed acquired early knowledge of science and mathematics.
  • Mother: Grace Peloubet Norton (1887–1943), born in Auburndale, Massachusetts. Moved to Chicago as a young child after the death of her father, Lewis M. Norton, who had developed the first course in chemical engineering at MIT in 1888. Grace’s mother founded the department of home economics at the University of Chicago. Grace became a school teacher. Ed stated that his mother “taught him more about life than anyone else” and fostered his deep interest in games, particularly chess.
  • Maternal grandfather: Lewis M. Norton – created MIT’s first chemical engineering course (1888)
  • Wife: Jane Loban (1919–2001), born in Dayton, Ohio, raised in Cedar Falls, Iowa. Her consuming interest was flying – she flew small airplanes before she was old enough to drive. Her interest in flying led to meteorology studies and a position as research assistant at MIT. Married Ed a few weeks after his doctorate (1948).
  • Children: Nancy, Edward (“Ned”), and Cheryl. All showed keen interest in games and puzzles; all became first-class downhill skiers.
  • Grandchildren: Four (at time of memoir)

Childhood and Early Life

Ed became fascinated with numbers at an early age. While his mother wheeled him down the street in a go-cart, young Ed would read out all the house numbers. After learning multiplication, he could recite all perfect squares between 1 and 10000. He spent hours extracting square roots by longhand and even learned a method for cube roots.

From his mother he developed a keen interest in games and learned to love card and board games of all kinds, including chess, at which he excelled – becoming captain of both his high school and college chess teams. At MIT, he would often spend lunch at the faculty club playing chess with colleagues, including Norbert Wiener, who routinely played simultaneous games with a set of his colleagues.

Ed loved crossword and jigsaw puzzles, competing with his father to solve them most rapidly and recording times on the inside covers of the boxes. He kept a collection of childhood jigsaw puzzles throughout his life.

At age seven, he discovered an atlas showing illustrations of the planets and was especially struck by Saturn, initiating a lifelong love of astronomy. A year later he witnessed a total solar eclipse on a bitterly cold day in Hartford, with shadow bands shimmering across fields of snow.

He had a good ear for music and could, by age three, tell that his mother was singing off key – “but he loved to listen to her anyway.” He began violin lessons at age nine but concluded he lacked the manual dexterity. His passion for music continued throughout life – he and Jane were avid patrons of the MIT student symphony orchestra and attended concerts at the Chautauqua resort in Boulder. In Lexington, Massachusetts, Ed was a member of the town choir.

Smaller than most boys his age and a year younger than classmates, Ed did not excel at team sports. But by high school he was an excellent swimmer (could swim underwater further than anyone) and discovered that his light weight let him reach mountain tops faster than most friends. “Mountains and music were his greatest spare-time interests.”

Education

  1. Dartmouth College (1934–1938) – A.B. in Mathematics. Of roughly 700 entering students, only seven majored in mathematics. Ed “preferred the logical clarity of math to any of the other courses.”
  2. Harvard University (1938–1940) – A.M. in Mathematics. Studied group theory, set theory, and combinatorial topology under Saunders Mac Lane, Marshall Stone, and James Van Vleck (later Nobel laureate in Physics). Worked on a problem in Riemannian geometry under George Birkhoff (an eminent mathematician best known for proving Poincare’s Last Geometric Theorem – a special case of the three-body problem exhibiting sensitive dependence on initial conditions).
  3. MIT (1942–1943) – S.M. in Meteorology. Eight-month Army Air Corps cadet programme. Ed’s memorable description: “It soon became evident that we were studying to be meteorologists. The distinction is one that I was slow to appreciate.”
  4. MIT (1948) – Sc.D. in Meteorology. Dissertation: “A Method of Applying the Hydrodynamic and Thermodynamic Equations to Atmospheric Models” (under James Murdoch Austin).

WWII Service

In 1942, just months before he expected to receive his doctoral degree in mathematics at Harvard, the war intervened. Ed chose between being drafted and training as a weather forecaster – and chose the latter.

After the eight-month MIT master’s programme and a year as an instructor there, Ed received orders to go overseas. He reported to Hawaii for two months of tropical meteorology training, then flew to Saipan in October 1944. With several Air Corps colleagues he helped set up a weather forecasting operation supporting bombing raids against Japan. His principal job was forecasting upper-level winds.

The forecasters were hampered by severe lack of observations. Ed complained that pilots, to save time, “would often simply repeat the forecast as the observation. This made for excellent forecast verification but hardly helped the forecasters make the next forecast.”

In spring 1945 the operation transferred to Guam, where Ed was appointed head of the upper-air section. A fellow forecaster, Patrick Suppes, later described Ed:

“Although Ed was not a strongly outgoing individual, it turned out that he rather liked conversation on many topics, and of course as those who knew Ed will find unsurprising, he knew a lot and was prepared to talk about a great many different subjects.”

Ed was nominated for (but did not receive) a Bronze Star medal. The nomination cited: “Through high order technical skill and resourcefulness, he utilized scientific principles to adapt known techniques and to devise new techniques of analysis and forecasting.”

Career Timeline (all at MIT)

Period Position
1948–1955 Research scientist, General Circulation Project (under Victor Starr)
1955 Promoted to assistant professor (Jule Charney made Ed’s promotion a condition of his own move to MIT)
1962 Promoted to professor
1977–1981 Head of Department of Meteorology
1987 Emeritus professor

Leave visits: Lowell Observatory (Flagstaff, Arizona); UCLA Department of Meteorology; Det Norske Meteorologiske Institutt (Oslo); National Center for Atmospheric Research (Boulder, Colorado).

Major Scientific Contributions

1. Available Potential Energy (1955)

Ed’s first important published contribution. He defined available potential energy (APE) as the difference between the nonkinetic energy of a given state and that of a reference state that minimises the nonkinetic energy under adiabatic rearrangement of mass. He then showed that mean-state APE (generated by latitudinal heating gradients) is first converted to eddy APE, then to eddy kinetic energy – establishing the Lorenz energy cycle that describes how the atmosphere’s circulation is powered.

2. The General Circulation of the Atmosphere (1967)

A landmark treatise: The Nature and Theory of the General Circulation of the Atmosphere (WMO, 1967) – “a beautifully crafted exposition of the main features of atmospheric circulation, still used as a starting point by students and professional researchers.”

3. Discovery of Deterministic Chaos (1961)

The LGP-30 Computer:

In 1958, Ed acquired a Royal McBee LGP-30 desktop computer for his office. It could make about 60 calculations per second and every minute would “clack out a line of numbers.” Ed wrote: “Suddenly I realized that my desire to do things with numbers would be fulfilled.”

Ed used a set of 12 ordinary differential equations (approximations to rotating stratified fluid equations) to test whether linear regression methods could match numerical forecasting. The solutions were nonperiodic, and the regression methods produced mediocre results, as Ed had foreseen.

The Coffee Break Discovery (1961):

At one point Ed wanted to examine a solution in greater detail. He stopped the computer and typed in 12 numbers from a printed row – but the printer showed only three decimal places (0.506) while the computer worked internally to six places (0.506127). He started the machine and stepped out for coffee.

When he returned about an hour later, the new solution did not agree with the original. At first he suspected machine trouble. But on closer examination, he saw the new solution matched the original for the first few time steps, then gradually diverged until the two solutions differed by as much as any two random states.

“At this point, I became rather excited,” Ed relates. He realised immediately that if the atmosphere behaved the same way, long-range weather prediction would be impossible owing to extreme sensitivity to initial conditions.

The Lorenz System:

Ed visited Barry Saltzmann, who showed him results from a seven-variable model of thermal convection. While most solutions were periodic, one set showed irregular variability. Ed noticed that in this solution, four of the seven variables settled to zero. Thus he realised chaotic solutions could exist in a three-variable system. This became the celebrated Lorenz (1963) model, exhibiting the fractal geometry later called a “strange attractor.”

Key publication: Lorenz, E. N. (1963). “Deterministic Nonperiodic Flow.” Journal of the Atmospheric Sciences 20: 130–141.

Collaborators: Margaret Hamilton (software engineer) and Ellen Fetter assisted with the computations.

4. The Butterfly Effect

From Seagull to Butterfly:

In his 1963 paper, Lorenz wrote: “One meteorologist remarked that if the theory were correct, one flap of a sea gull’s wings would be enough to alter the course of the weather forever.” Following suggestions from colleagues, Lorenz later adopted the more poetic butterfly image.

When Lorenz failed to provide a title for a 1972 talk at the American Association for the Advancement of Science, Philip Merilees concocted the now-famous title: “Does the Flap of a Butterfly’s Wings in Brazil Set Off a Tornado in Texas?”

5. Two-Week Predictability Limit

Lorenz concluded that weather prediction was fundamentally impossible beyond roughly two to three weeks owing to the exponential growth of small errors. He estimated that errors in the pressure field roughly 5 km above the surface doubled approximately every 2.5 days (in the models available at the time), though he warned this might decrease as spatial resolution improved.

6. Ensemble Forecasting (1964)

Ed suggested that since the initial state of the atmosphere can never be known precisely, one should make a large number of numerical forecasts, each starting from slightly different but equally likely initial states. The mean of the different integrations is likely to be a better forecast than a single arbitrary integration. Today, ensemble numerical weather prediction is a bedrock tool at all leading forecast centres worldwide.

7. The Slow Manifold (1986)

In a landmark 1986 paper, Ed showed that while manifolds that are locally invariant and locally slow do exist, global slow manifolds do not – related to the spontaneous generation of fast gravity waves in otherwise slowly evolving systems.

8. Adaptive Atmospheric Sampling (late 1990s)

Using a 40-variable model, Ed showed that targeting observations where the prior estimate is most likely to be in error significantly improved forecasts compared to random or fixed observations.

Personal Characteristics

The Quiet Gentleman

Kerry Emanuel (his NAS memoirist) wrote: “Those of us privileged to have known Ed Lorenz will remember him as a gentle, quiet soul, almost painfully shy and modest to a fault. But engage him on a favorite topic – a fine point in atmospheric or dynamical systems theory, the virtues of a particular mountain trail, or anything to do with his extended family – and with a twinkle of his bright blue eyes he would come to life.”

Jule Charney described Lorenz as having “a soul of an artist.”

Outdoorsman

Ed was an avid hiker, mountain climber, and cross-country skier. He maintained these pursuits until approximately two weeks before his death at age 90. He loved the mountains of New Hampshire (Waterville Valley, where his parents had honeymooned) and spent many summers there. His family became first-class downhill skiers: “Many of my winter weekends were spent taking one or all of them, usually with my wife as well, to some ski area north of Boston; this, of course, was just what I had hoped would happen.”

Devotion to Family

Ed’s devotion to his family was evident to all. When Jane suffered debilitating illnesses toward the end of her life, Ed set aside his research and other interests to care for her. After her death in 2001, he returned to research, publishing another nine or so articles before his own death.

Teaching

Ed was “much beloved as a teacher and for many years running won the prize awarded by MIT graduate students for the best teacher of the year.” When invited to visit families of colleagues, he would invariably bring “wonderful, usually mathematics-based toys for the children.”

The American Meteorological Society named its Edward N. Lorenz Teaching Excellence Award in his honour.

Weather Enthusiast

Generations of MIT students and colleagues remembered occasions when Ed would “appear silently in their office, as if by magic, and enthuse over some feature of the current weather map.”

Mentor: Victor Starr

Victor Starr, who headed the General Circulation Project, became Ed’s mentor and close friend. In Ed’s words: “The things I remember best and cherish most, in looking back over my scientific career, are the almost daily conversations with Victor Starr during the more than twenty-five years that I worked with him.”

On Free Will

From The Essence of Chaos (1993): “We must wholeheartedly believe in free will. If free will is a reality, we shall have made the correct choice. If it is not, we shall still not have made an incorrect choice, because we shall not have made any choice at all, not having a free will to do so.”

Honours and Awards

Award Year
Carl-Gustaf Rossby Research Medal (AMS) 1969
Symons Gold Medal (Royal Meteorological Society) 1973
National Academy of Sciences (elected) 1975
Member, Norwegian Academy of Science and Letters 1981
Crafoord Prize (Royal Swedish Academy, with Henry Stommel) 1983
Honorary Member, Royal Meteorological Society 1984
Elliott Cresson Medal (Franklin Institute) 1989
Kyoto Prize (Inamori Foundation, earth and planetary sciences) 1991
Roger Revelle Medal (American Geophysical Union) 1992
International Meteorological Organization Prize (WMO) 2000
Buys Ballot Medal (Royal Netherlands Academy) 2004
Lomonosov Gold Medal (Russian Academy of Sciences) 2004
Felice Pietro Chisesi e Caterina Tomassoni Award 2008

The 1991 Kyoto Prize committee stated: his discovery of deterministic chaos “profoundly influenced a wide range of basic sciences and brought about one of the most dramatic changes in mankind’s view of nature since Sir Isaac Newton.”

Connections to Other NWP Pioneers

  • Jule Charney: Charney made Lorenz’s promotion to the MIT faculty a condition of his own acceptance of the MIT position. The two were colleagues for 25 years. Charney described Lorenz as having “a soul of an artist.” Lorenz’s chaos work demonstrated the fundamental limits of the weather prediction programme that Charney had done so much to establish.
  • Norman Phillips: Fellow MIT colleague; Lorenz visited Phillips and Charney at the IAS before joining the faculty. Lorenz and Phillips worked on complementary problems in atmospheric dynamics.
  • Victor Starr: Lorenz’s mentor and closest intellectual companion at MIT for over 25 years.
  • Jacob Bjerknes and Jorgen Holmboe: Lorenz visited UCLA in 1953 and met both. Formed a lifelong friendship with Arnt Eliassen during this visit.
  • Lewis Fry Richardson: Lorenz’s discovery showed why Richardson’s dream of deterministic long-range prediction was impossible in principle.
  • Barry Saltzmann: Showed Lorenz the convection model from which the three-variable Lorenz system emerged.

Death and Legacy

Ed died at home in Cambridge on 16 April 2008, surrounded by family, having worked on proofs of his latest paper just days earlier. A memorial service was held on 20 April at the Swedenborg Chapel, Cambridge.

Kerry Emanuel wrote: “By showing that certain deterministic systems have formal predictability limits, Ed put the last nail in the coffin of the Cartesian universe and fomented what some have called the third scientific revolution of the 20th century, following on the heels of relativity and quantum physics.”

The Lorenz Center, a climate think tank devoted to fundamental scientific inquiry, was founded at MIT in 2011.

In February 2018, MIT held a “Chaos and Climate” symposium celebrating the centennial of both Lorenz’s and Charney’s births (both born in 1917).

Sources

  • Emanuel, K. “Edward Norton Lorenz, 1917–2008.” Biographical Memoirs (National Academy of Sciences), 2011. https://texmex.mit.edu/pub/emanuel/PAPERS/Lorenz_Edward.pdf – Accessed: 2026-04-02
  • Palmer, T. N. “Edward Norton Lorenz. 23 May 1917 – 16 April 2008.” Biographical Memoirs of Fellows of the Royal Society 55 (2009): 139–169. https://royalsocietypublishing.org/doi/10.1098/rsbm.2009.0004 – Accessed: 2026-04-02
  • “Edward Norton Lorenz.” Wikipedia. https://en.wikipedia.org/wiki/Edward_Norton_Lorenz – Accessed: 2026-04-02
  • “Edward Lorenz, father of chaos theory and butterfly effect, dies at 90.” MIT News, 16 April 2008. https://news.mit.edu/2008/obit-lorenz-0416 – Accessed: 2026-04-02
  • “Edward Lorenz.” Britannica. https://www.britannica.com/biography/Edward-Lorenz – Accessed: 2026-04-02
  • “Butterfly effect.” Wikipedia. https://en.wikipedia.org/wiki/Butterfly_effect – Accessed: 2026-04-02
  • Lorenz, E. N. (1963). “Deterministic Nonperiodic Flow.” Journal of the Atmospheric Sciences 20: 130–141.
  • Lorenz, E. N. (1993). The Essence of Chaos. University of Washington Press.
  • Lorenz, E. N. “A Scientist by Choice” (autobiographical note, unpublished).