Climate research centres around the world have developed and constantly improved climate models that can help us plan for the future. These models are based on well-established physical principles and tend to produce outcomes that are broadly consistent, in terms of trends and their general magnitudes, when they use the same emissions scenario.
However, there are differences in how each research group represents important features of our climate, such as clouds, that affect how the climate will respond to different emissions scenarios. Thus, the models produce a range of outcomes, and so, we’ll see a range of possible futures even when the models use the same emissions scenario.
We’re accustomed to seeing such ranges in other instances in which model outputs are used in decision-making. For example, when a hurricane is approaching land, the forecasted track is shown as a cone that encompasses the range of model projections for the storm’s path. Though we can’t predict the exact path, communities within the cone know to be prepared. Having this kind of range lends confidence that people won’t be caught off-guard.
Similarly, the range produced by a set of climate models lends confidence that our planning will be effective.