The data points included in Timeline are drawn from different sources. They are each the result of a different methodology, are based on differing assumptions and models, and have been through a different validation process. Each data point is accompanied by its source; to assess data or use it in decision-making, always refer to its full context. Data is not neutral, and selection of data also carries bias.

Timeline prioritises data from studies with robust methodologies and respected sources. It also makes space for some clearly-denoted wildcards.

Preference is given to the most recent forecasts, mid-range or median scenarios, and projections based on current policies. Data points are based on UN climate change projections (currently 2.8 degrees) or are otherwise noted according to the pathway (e.g. ‘at 3 degrees+’). Some wildcard projections are included for technological changes. Wildcard projections are marked ⚡︎ and are sourced from well-respected industry figures with strong records.

We prioritise data points from studies with:

• A disclosed and robust methodology

• A reputable source or author. This includes data points that have been published in a respected journal, by an institute with a strong track record, or in some cases, by an individual or organisation with a strong track record and good standing in their area of expertise

• A recent publication date or recent update

• Peer review or a similar process of verification

• Disclosed funding and institutional affiliation, and no obvious disqualifying bias of authorship or funding