The Jerrabomberra wetlands

13 April 2011 – Climate risk assessment of sea level rises changed the height of a bridge in Canada according to a report by two Australian scientists for the Organisation for Economic Cooperation and Development, whose findings on environmental impact assessments have attracted international interest including from the World Bank.

Principal scientist, Marcus Sainsbury and senior scientist, Guillaume Prudent-Richard from the global professional technical services consultancy AECOM, who  co-authored the report found that Australia, Canada and the Netherlands are leading the world in EIA.

For example, in Canada, EIA guidelines used to design the 27 kilometre long Confederation Bridge between New Brunswick and Prince Edward considered the effects of the bridge on the environment and vice versa. The goal was to develop structural requirements considering a design life of 100 years over which the bridge could withstand all probable stresses, including from ice and wind and incorporated safety factors to minimise climate change risks.

As a result the bridge was built higher than required to accommodate projections of sea level rise. A monitoring program of water temperatures, currents, coastal erosion, coastal sediment transport, and ice conditions affecting the bridge gave early warning of unanticipated changes, to allow adjustments.

In Australia, although there is no national framework for the consideration of climate change adaptation in EIA, planners in some states and territories such as the ACT and NSW require a climate change risk assessment.

The East Lakes electrical infrastructure project on the banks of Lake Burley Griffin in Canberra, next to the Jerrabomberra wetlands, triggered an EIA and climate change risk assessment because flood studies in the area showed that by 2030 there would be a moderate risk of it being flooded, due to an increase in extreme daily rainfall events, and the intensity and frequency of storms. This would result in a less reliable electricity supply and increased costs associated with repairs and infrastructure replacement, the report said.

The EIA recommended that all electrical equipment in the sub-station should be placed about two metres above the probable maximum flood level to avoid potential future flood risks. The effects of climate change also included extended dry periods, resulting in increased dust build-up and potential transformer failures. The design of structures included a significant safety margin to minimise the risk of catastrophic failure and operational procedures including maintenance and reacting to spills and other major failure events.

In the Netherlands, the plan, “Room for Rivers” defined the necessary measures to protect the Netherlands against flooding of the river Rhine in the coming decades, while incorporating climate change scenarios, the report said. This scheme  introduced a combination of measures from dike improvement or heightening; to creating more space for water discharge or retention in the river foreland or river bed.  For example, through the removal of obstacles, deepening of the riverbed, creation of retention ponds, and relocation of dikes.

Climate change considerations were integrated in view of the high water levels expected for 2020 and possible developments in the upstream sections of the river in other countries such as Germany.

Small Island Developing States in the Caribbean and South Pacific also planned to  examine using climate change impacts in their EIA process, and the European Commission was reviewing their EIA guidelines, Mr Sainsbury said in a media statement.

The report concludes that to a large extent the goal of incorporating climate change impacts and adaptation within environmental assessments remains more aspirational than operational.

Projects can be sensitive to a broad set of climate related variables that range from increases in temperature to changes in rainfall, stream flow, permafrost thickness, and wind intensity. Climate models, however, can project certain variables better than others. For example, temperature increase is easier to project than sea level rise or changes in rainfall, which, in turn, are easier to project than  changes in wind intensity.

A key bottleneck was the availability of detailed information on the historical climate, as well as fairly specific scenarios of future climate for the project location. There was also the risk of unnecessary or even counterproductive investments in altering project design if the uncertainties associated with climate change projections were  not adequately considered.

See the full OECD report