We've all been in situations where not knowing what will happen in the future requires contingency plans. For example, if sunny weather holds out, we will have our picnic. But if it rains, we will meet in the shelter. By developing these "if-then" scenarios for future conditions, we are engaging in a form of adaptation planning.
Now imagine being a city planner or hydrologic engineer responsible for designing and implementing new storm water structures that are meant to last for the next fifty years. If you design these structures based on the weather from the last fifty years, they might lack sufficient capacity to handle rain storms of increasing intensity and frequency, perhaps leading to flooded streets and homes. On the other hand, if you plan for the worst-case scenario even though there is a small probability of it happening, you may over-design the system at a significant cost to the taxpayer if those extreme events do not materialize.
This conundrum represents the world of adaptation science. At a fundamental level, there are only two parts to adaptation science; calculating the probability of a future event, and creating contingency plans for those events most likely to materialize. Adaptation should focus on the greatest vulnerabilities. In short, where are the greatest risks if climate changes occur? Identifying these vulnerable locations or situations, and then creating a range of contingency plans, is the focus of many WICCI Working Groups.