3 October 2017
Because of climate change, the climate we experienced in the past is no longer a reliable indicator of the climate we will experience in the future. This makes planning ahead a challenge. Climate projections are the best tools we have for understanding and planning for climate change, but in the short term, it can be difficult to separate out the effects of climate change from the effects of natural climate variability.
Understanding climate change and climate variability
Climate change (due to human activities) and climate variability (the natural variations in climate from year to year or decade to decade) are both influencing our current and future climate.
To understand how, think about rolling a dice with sides numbered from 1 to 6. From roll to roll you get different numbers, but the average comes out close to 3.5. For our purposes, the average is the climate and the different numbers on each roll are the climate variability. The effect of climate change is to change our dice from one numbered 1 to 6, to one numbered 2 to 7. We still get different numbers from roll to roll, but the average is now 4.5. The chances of getting a higher number are increased, the chance of a lower number is reduced, and rolling a 1 is now impossible.
Planning for the future
We can’t readily distinguish climate changes from background climate variability until we are dealing with timescales longer than a decade, so generally, around 2030 is the earliest future period where we can realistically examine climate change.
So, while climate projections are a useful planning tool, we can’t forget about climate variability – particularly when we’re using projections to make plans for the next 10–20 years (an important timeframe for many decisions in agriculture, forestry, water management, infrastructure and environmental management).
Using climate change information to 2030
When using climate projections to 2030, it is important to:
- understand climate variability – look at the full range of observations available and understand your climate risk in the past and current climate, understand the relevant processes involved (e.g. El Niño events)
- understand the range of projections – use the Climate Futures tool to explore ranges of change for the relevant climate variables
- put variability and change in perspective, and what this means to you. For example, you might explore if and where climate change makes an important difference to the odds of crossing an important threshold, then assess how you can manage these changing odds. It may be best to plan for the full range of current climate variability.
It is also important to:
- understand your climate exposure – what aspects of the climate affect your area of interest? Which variables, and which aspects of the climate? What are the key climate thresholds or relationships?
- consider other changes that are relevant (e.g. regulation, population change, new technology)
- consider if your planning horizon extends beyond 2030. If you need to look ahead to 2050, 2070 or 2090, you will need to consider the different emissions scenarios, as their influence becomes greater than climate variability.
For more information, download Our changing climate: using climate change information to 2030.