Calculator works out the price of sustainable transition

How can I live more sustainably? Most people know how to reduce their carbon footprint – eat less meat, limit air travel, and provide better insulation of the home. But how many know how to weigh up the different actions against one another for maximum effect?

Associate Professors Kristian Mølhave (DTU Nanotech) and Stig Irving Olsen (DTU Management Engingeering) decided to solve this task with the help of a group of students. Their efforts resulted in the Sustainability Calculator, which was tested by several families in connection with Green Future sustainability festival in Lyngby, Denmark, on 2 June.

The media tends to focus on household carbon emission, but sustainable transition is about a great deal more than CO2. According to researchers, it should also address other parameters – e.g. how much water or other resources are consumed, how biodiversity is affected, etc.

Companies like Novo Nordisk and Arla employ a calculation tool called Natural Capital Accounting, which converts the environmental effect of different actions into monetary terms so they can gain an overview of how and where they need to act to get the most out of their green investment. A calculation might involve weighing up the environmental impact of taking a flight, for example, by purchasing CO2 quotas and planting some trees to balance things out.

While the method is still in development and contains uncertainties, it nonetheless provides a means of balancing the numerous factors and a basis for decision making. And what if you could get a similar guide on the easiest way to change your personal lifestyle in order to achieve maximum sustainability? Avoid wasting time as well as money.

Kristian, Stig and the students have tried to show this with their sustainability calculator, which can calculate the cost of a person’s private consumption habits, the size of the problem, and how best to do something about it. The sustainability calculator has been tested by several families in Lyngby, Denmark, who wanted to change their habits in order to become as sustainable as possible—and all the families felt the calculator gave a good overview of how much difference their efforts really made.

“The figures you get are a bit like a prediction of stock prices or a 14-day weather forecast, but they still give an overview of what you can do to avoid wasting time and money on changes that have minimal effect,” says Kristian.

Many people view the environment as a huge unmanageable problem, but one of the positive things about the calculator was that it showed that a person’s environmental costs often only amount to about one-tenth of an annual salary. This shows that it should be possible to make life much more sustainable for the individual – or for society, which can levy appropriate taxes.

“It should be pointed out, however, that the methods for calculating environmental costs still lack a number of environmental impacts, so the cost is therefore presumably higher,” says Kristian.

An online version of the calculator is available at