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General change of footprint

Get personalised tips on how to reduce your climate footprint based on your habits and household data.

All inputs, outputs and defaults can be seen in the Change general technical API docs.


This endpoint receives as input:

  • a dataset (country) to base calculations on
  • a list of habits and a household description (specific questions are defined under different categories, as explained in the chapter on calculations)
  • filtering criteria for tips
    • module (energy, food and drink, goods and services or transport)
    • financial cost of completing the tip
    • time required to complete the tip
    • social difficulty
    • points
  • number of tips to output
  • ordering of tips, as so to output the most valuable or simple ones
    • by kg CO2e saved (descending order)
    • by points earned (descending order)
    • by money saved (descending order)
    • by cost (ascending order)
    • by time required (ascending order)
    • by perceived social difficulty (ascending order)
  • language to display the output text

All inputs are optional, with default values defined in case of missing inputs. If no dataset is given, Norway is used by default. If no habits or household info are provided, the calculation will assume default answers which match an average person from the data source specified. If no filtering criteria are provided, none are applied. If the number of tips to output is not given, the entire list of tips is given. If no ordering is provided, kg CO2e saved is used as default. If no language is specified, Norwegian is used by default.

Description of filtering criteria

Filtering by module enables a developer to set up the Change endpoint for use in a specific sector, e.g. just delivering transport tips for a ticket purchasing app.

Filtering by points allows a developer or user to choose a general level of impact that is appropriate for the context. Points are allocated based on the following options: individual (5 points, eg. biking to work instead of using the car), social (10 points, eg. convince your friend to buy second-hand instead of buying new) and community impact (15 points, eg. talking to your local politician to implement a car tax in your neighbourhood). High point scores mean a large indirect impact or handprint.

Each tip also has a set of investment attributes which describe the different types of costs associated with the tip. Filtering on these attributes allows a user to start out with free and simple tips and only be presented with high investment tips when the context is right:

  • The financial cost of performing each tip is based on the average prices of the equipment/services needed for the tip. The absolute prices of each equipment or service are converted to an order of magnitude scale with the following options:  less than 10€, 10- 100€, 100-1000€, 1000–10000€, greater than 10000€.
  • The time required is the time taken from initiating a tip to its completion (eg. if a user decides to move to a new house, this would be a project that takes months - the time required to complete the tip would then be months, even if they are not spending all their time moving). The time investment is split into the following options: minutes, hours, days and months.
  • The social difficulty is based on the perceived difficulty of performing a tip. The social investment is split into following options: socially acceptable (easy to do), inconvenient (moderately easy to do) and breaks social norms (requires effort to do). For example the tip “avoid over-purchasing food” would be classified as socially acceptable since it is rather easy to perform, but the tip “walk to work instead of taking the car” would be classified as inconvenient since it involves a bit more effort.


This endpoint returns a list of actions the user can undertake to lower their CO2e emissions by practising more sustainable behaviour. For each tip, the following attributes are displayed:

  • title: name of the tip
  • description: a short summary describing the tip
  • id: unique identifier assigned to the tip
  • module: one of food and drink, transport, energy or goods and services
  • tags: labels used to categorise tips
  • indicators: metrics used to evaluate the impact of the tip
    • biodiversity
    • kg CO2e saved (per day unless otherwise specified)
    • health benefits 
    • land use
    • points
    • time
    • money saved
    • social
  • investments: costs of performing the tip
    • financial cost
    • social difficulty
    • time required

The user can filter and order tips based on indicators and investments.  The indicators give insight into each tip’s impact. They can be classified as quantitative or qualitative. The quantitative indicators have a numerical value quantifying their impact, meanwhile the qualitative indicators do not have a numerical value but instead contain only a textual description. 

The qualitative indicators (biodiversity, land use, health benefits, and social) describe the positive effect of performing a tip. For example, for the activity “walking or biking to work instead of taking the car”, the health benefits associated with walking and biking are highlighted (lower chance of obesity and diabetes), as are the positive impact on biodiversity due to lower microplastics emissions as a result of not taking the car.


Each tip is an action the user can perform to lower their carbon footprint. The tips are calculated by first calculating the current footprint of the person’s input habits, then calculating the footprint of the person with an input changed accordingly so as to reflect the lifestyle change of the tip. The difference between the two footprints is then the CO2e savings.  The footprint is calculated using the same logic as in the Calculate endpoint  (see documentation here).  Based on the filtering criteria, we calculate all applicable tips and return the most relevant ones.