This text is part of the special Research section: climate issues
To have a global vision of the impact of human activities on the Earth, researchers analyzed them on the scale of a day.
In Earth systems science, we view the planet as a system. “Humans are part of this system, but in traditional analyses, they are only considered as a source of greenhouse gas emissions,” says William Fajzel, doctoral student at McGill University. However, as the analysis of the coal cycle showed in the 1980s, it is essential to better understand these systems to understand the Earth and climate change.
A better overview
“We know a lot about local interactions, but we have few tools to understand how it works on a global scale,” says Eric Galbraith, professor of Earth system sciences at McGill University and holder of the Chair of Canadian research in the dynamics of the human-terrestrial system.
Hence the importance of taking a step back. “We need a holistic picture of what humans do. Without that, we cannot tackle the problems,” underlines Mr. Fajzel. As part of William Fajzel’s studies, Eric Galbraith and his team therefore decided to compile the activities of the planet and bring them back to 24 hours, a universal time scale. “With this constant scale, we can really know what is happening in the world,” says Mr. Galbraith. The results were published in the scientific journal PNAS in June.
Compile human activities
The team decided to use time as a unit of measurement “to better understand what humans are doing on this planet in crisis,” summarizes Mr. Fajzel. “We just wanted to quantify human activities on a larger scale. Surprisingly, no one had done it before,” says Galbraith. They used activity surveys conducted by governments around the world, where participants were asked to fill out a 24-hour activity diary.
This long work was spread over two years. “The data existed, but it was not centralized,” notes Mr. Fajzel. These data were not uniform, the lexicon of activities being sometimes restricted to around ten activities, sometimes up to a hundred. “We tried to describe the activities in an unambiguous way that worked across cultures,” says Galbraith. The data was compiled by country and age, before taking a daily average for the entire planet.
Little time, lots of impact
First observation: humans spend a lot of time doing activities for themselves and others. Sleeping is the activity that takes up the most time (nine hours on average); follow hygiene care, medical care and care of loved ones, and passive activities (relaxing, watching television). All these activities, which have no impact on the planet (excluding the production of goods related to them), total approximately 18 hours 30 minutes per day on a planetary scale. In the remaining time, approximately two hours are allocated to organizational activities: commerce, finance, governance, transport of humans and products. Thus, over a period of 24 hours, just three and a half hours profoundly change the planet, locally and globally, for activities such as the construction of buildings, infrastructure, manufacturing, the production of food and energy, etc.
“The majority of the time, humans carry out activities without impact. These passive, social and interactive activities are also the most enjoyable for them, observes Mr. Fajzel. In contrast, the activities responsible for the planetary crisis (i.e. the extraction of energy and matter) occupy approximately 10 minutes of a planetary day. »
Give hope
This study opens a different perspective and gives hope in the face of the colossal task of confronting climate change. “If we double the time taken to take care of an activity that requires very little time, that still leaves very little time,” points out Mr. Fajzel.
If we devoted more time, on a global scale, to waste management, for example, a lot could be accomplished. Currently, only one to two minutes per day are spent on recycling, managing domestic and industrial waste and sewers. “It’s not surprising that we have a lot of problems with this waste management… It shows that we have the capacity to do more,” explains Mr. Galbraith.
Such an analysis also completely changes the perception we have of energy production. “It is said that it is very difficult to stop using fossil fuels, because it takes up a large part of the economy. But, in fact, on an international scale, that’s two minutes a day. We therefore have a lot of time available to build a new energy system,” believes Mr. Galbraith.
It is therefore not due to lack of time that changes are not made, but rather due to lack of political will, or due to other obstacles (economic, organizational, etc.). “Now that I see how humans spend their time, it gives hope: there are possibilities to combat climate issues and promote the circular economy,” concludes Mr. Galbraith.
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