Why we look at extremes

We need to consider the full range of possible scenarios to assess whether we are doing enough to invest wisely and adapt to climate change.

The Ministry for the Environment’s 2017 climate change planning guidelines for councils, tells us to consider the total range of international greenhouse gas concentration trajectories (called RCPs), from RCP2.6 to RCP8.5+. These describe different climate futures, all of which are considered possible depending on the volume of greenhouse gases emitted globally in the years to come.

The guidance says the upper scenarios need to be considered by decision-makers to ‘stress test’ greenfield development (new suburbs or towns) or major new or upgraded infrastructure projects to be sure they won’t be affected by coastal hazards during their anticipated lifetimes.

It’s the right thing to do when we’re spending millions of dollars on developments that we want to last many, many decades.