Even though climate change is beyond doubt, planning for it involves uncertainty as to exactly how its impacts will progress and how fast. That calls for a flexible approach to building resilience, using adaption pathways to decide and act in a measured, affordable and effective way.
Modelling of earth systems is at the heart of climate science, telling us what changes to expect in temperature, precipitation, sea level rise and acute weather events. Although climate models are calibrated to the observed climate, forecasts of future change come with ranges of uncertainty.
“When we talk about climate science, we talk about climate change projections, not predictions,” explains Kiki Pattenden, principal consultant in climate resilience at Mott MacDonald. Uncertainty stems from some big unknowns: our ability to meet global emission reduction targets; political determination to cut emissions and the use of regulation and legislation to turn intentions into actions; and localised variations in climatic response, for example the changes to the El Nino Southern Oscillation or on the severity typhoons.
That makes it difficult to say with absolute certainty how climate change will affect the frequency and magnitude of the climate hazards that impact our infrastructure and society in any particular location – particularly into the long term (beyond 2050). “We know with absolute certainty that climate change will have an effect on our systems and we can model potential impacts. But we need to consider a range of possible scenarios,” says Kiki.
So how best to respond when the future looks ambiguous?
The answer lies in developing climate adaptation pathways. Pathways embrace uncertainty and allow organisations to respond in a planned but flexible way to observed and projected changes. Various ‘if-then’ scenarios are mapped. Outline design options are drawn up for a range of possible futures, but action is only triggered when the effects of climate change approach defined risk thresholds.
This makes clients and communities agile. If climate change results in rapid sea level rise, there is a resilience plan to implement. However, if the rise is more gradual, then protection can be pushed back, and investment deferred. If over time the trajectory of emissions alters the risk profile or the vulnerability – changing land use, the number of people or value of assets – then different options become possible. Adaptive pathways keep options open, allowing the right resilience measures to be implemented at the right time and avoiding expenditure before it is necessary.
We successfully applied an adaptive approach in Singapore as part of the country’s second national climate change study, developing pathways for energy and telecommunications infrastructure 10, 20 and 90 years into the future. Our adaptation plans identified the relative threats to assets under various future climate scenarios.
In Ireland, we partnered with the government’s water services and infrastructure sector officials to appropriately structure adaptation decision-making for the short and (more uncertain) long term. The resulting adaptation plan is a ‘live’ document – to be evaluated and reviewed to account for changing science and socio-economic conditions via existing government monitoring mechanisms (including Water Policy Advisory Committee and water governance reports). This marked a first in climate change adaptation planning for Ireland’s water sector.
Adaptation pathways recognise that building resilience requires a dynamic, long-term and flexible approach. By looking ahead and planning for uncertainty, they avoid the time and cost of repeated design cycles. They set out trigger points for decision-making and action – if a given threshold is reached, then an adaptive response is required.
Adaptive resilience can benefit communities as well as asset owners and investors. Adaptation plans are, by their nature, forward-looking and pre-emptive, not reactive. The process of putting a resilience strategy in place offers the opportunity to engage communities, helping to create solutions that support wider environmental and socioeconomic development plans,
All adaptation pathways should be consulted on and agreed as part of long-term local strategies for improving local lives.