Press release | 11 August 2020 | sn

The Ecological Inventory of a Person

Scientists have calculated the first life cycle assessment for a 50-year-old man / Book on the “Green Zero Project” published

The first ever life cycle assessment of a single individual was calculated at the TU Berlin Chair of Sustainable Engineering. Until now, TU Berlin researchers had calculated such life cycle assessments for products and production processes starting with the cultivation of raw materials, then production and use through to disposal. “A life cycle assessment for a single person did not exist until now,” says Professor Dr. Matthias Finkbeiner, head of both the Chair of Sustainable Engineering and the project “Life-LCA - Life cycle impacts of a human being”. The project also included developing and implementing measures to improve the ecological footprint of one's lifestyle.

The good and bad news

The result: Within one year, Dr. Dirk Gratzel, a 52-year-old entrepreneur from outside Aachen, North Rhine-Westphalia, succeeded in shrinking his carbon footprint from an initial 27 tons annually to 7.8 tons. “This outcome surprised us. We didn’t expect such a drastic reduction. This is good news,” says Matthias Finkbeiner. “However, the bad news is that 7.8 tons of carbon emissions per person each year is still significantly higher than the annual 1.5 to 2 tons per person deemed sustainable by the Intergovernmental Panel on Climate Change.”

From a single sock to the car

In 2017, Dirk Gratzel contacted Matthias Finkbeiner with an unusual request: He wanted to leave the earth one day without an ecological footprint and wanted Finkbeiner to tell him how to achieve this. Gratzel has now written a book titled “Projekt Green Zero” about his self-experiment and collaboration with Professor Dr. Matthias Finkbeiner.

They began by calculating Gratzel’s carbon footprint as precisely as possible, starting from birth. This required Gratzel to record his entire life in minute detail, including his everyday routine, diet, all his possessions from a single sock to his car, his home, hobbies, and even his trash, which he meticulously sorted. This information, which amounted to more than one hundred data sets, was used to calculate how much ecological damage Gratzel had caused, in other words his carbon footprint. The information also allowed the researchers to determine which behaviors and components had the greatest impact on Gratzel's ecological balance sheet. Using this, Gratzel worked together with environmental organizations to develop and implement measures to bring him closer to his goal of leaving behind an “ecologically sound” legacy.

“Creating a life cycle assessment for a single individual was also new for us.”

Matthias Finkbeiner’s team already had experience calculating carbon footprints and creating life cycle assessments on a larger scale – for milk, cotton t-shirts, and marble, for instance. They are leading experts in this field. “Creating a life cycle assessment for a single individual, though, was new for us and a tremendous challenge,” explains Finkbeiner. “We had to determine the appropriate methodology. For instance, whether we would include the life of Gretzel’s five children in the life cycle assessment and how to calculate the use of his house, where they lived as a seven-person family until his children grew up,” says Finkbeiner.

To create a life cycle assessment of products and production processes, the TU Berlin scientists consider up to 15 indicators which impact the environment. “In order to keep the project manageable and attain reliable numbers, we had to limit ourselves to five environmental parameters or impact categories when looking at Gratzel’s life: climate change, eutrophication and acidification of waterbodies and the soil, ozone depletion, and smog,” he says.

An absolute disaster: 27 tons of carbon per year

For three months Dirk Gratzel kept a detailed inventory of his previous and current life according to the guidelines set by Finkbeiner’s team. He documented what he ate and drank every day, how long he showered, what he owned – his toothbrush, underwear, cuff links, suits, plates, cups, electrical devices, a fondue set, all the way up to his Jaguar SUV and his listed-building home. He recorded what his suits are made out of and where they were made, where his morning coffee is from, how much electricity and water he uses, and how many kilometers he flies and drives. He sorted his garbage into eight different materials and weighed it, and even documented what and how much his dog ate. Later analysis of the data showed that a dog like his has a fairly sizeable ecological footprint.

The life cycle assessment of Gratzel’s life up until 2018 was an absolute disaster: He had emitted 27 tons of carbon each year. In comparison, the German average is ten to eleven tons, with those in Westphalia emitting an average of 13.5 tons. Dirk Gratzel, however, was releasing twice as much carbon dioxide into the air each year. Over 50 years, his lifetime emissions amounted to 1147 tons. The primary source of those 27 tons of carbon per year were his business and personal travel by car and plane; a diet heavy in meat, milk, and cheese; the energy consumption of his house; but also his dog.

Canceled: No meat or flying

From these main causes, roughly 60 measures were developed to reduce his carbon emission and help Gratzel attain his ultimate goal of a balanced ecological footprint by the time of his death. Implementing these measures led Gratzel to radically change his life: no air travel, a mix of driving a car and an increased focus on taking public transportation like buses and trains, no more industrially produced meat. Instead he only eats what he shoots himself as a hunter. Additionally, he no longer consumes dairy products, only uses seasonal, regional vegetables, updated the insulation in his home, and limits his showers to 45 seconds – to name just a few of the changes he made. He did not manage to cut out his daily morning coffee, nor could he give up his dog Emil.

A second life cycle assessment for Gratzel’s drastically changed lifestyle was then calculated by the Chair of Sustainable Engineering. Gratzel once again had to record a complete inventory of his life under the new conditions. As a result of the roughly 60 measures, he reduced his carbon footprint from 27 tons to 7.8 tons per year. Finkbeiner finds this result impressive and clear proof that flying, car emissions, and meat consumption are harmful to the climate and thus the planet. However, it also shows how far Dirk Gratzel still is from attaining the 2-ton goal recommended by the Intergovernmental Panel on Climate Change. “Given the fact that this result was only achieved through an extreme change in lifestyle, which included painful cuts, we have to ask how realistic the 2-ton goal is in our Western world, if we continue to adhere to the minimum standards of our civilized world, such as food, clothing, housing, work, education, healthcare, digital communication, mobility, and culture,” says Finkbeiner adopting a deliberately provocative stance “or whether we can only achieve this goal if we live naked in tents.” Finkbeiner admits he does not have the answer.

Healing the man-made damage

The Gratzel project was an “incredible inspiration” for both his research and himself: New projects have been initiated and findings clearly confirmed, namely that frequent air travel and trips by car have a great impact on the climate and that changing consumer behavior is by no means useless. He also gained some surprising insights, such as that a dog can have a not-so-minor impact on the environment and, in Gratzel’s case, that chemical products such as detergent, cleaning products, and cosmetics are a much lesser “environmental sin” than dairy products. Furthermore, facts aside, the work in this project has repeatedly made him aware that even an extremely reduced Western lifestyle significantly burdens the earth.

Finkbeiner believes a life without a carbon footprint is simply unrealistic. This is why he and Gratzel are looking at the topic of compensation in a third phase of the project and are thinking about concepts such as the renaturation of destroyed ecosystems. “We will have to find ways to heal the damage that has been caused. Simply compensating for it virtually will not be enough. The topic of scientifically robust reparation through the restoration of ecosystems will play a major role in future research,” says Finkbeiner.


Dirk Gratzel, with a forward by Eckart von Hirschhausen, Projekt Green Zero. Können wir klimaneutral leben? Mein konsequenter Weg zu einer ausgeglichenen Ökobilanz, Verlag Ludwig, 256 pages, EUR 18

Further Information

Press release "A Dog’s Life and Carbon Footprint" (28 August 2020)


Prof. Dr.

Matthias Finkbeiner