Hazard planning, awareness and building resilient communities

Hazard planning, awareness and building resilient communities

Sea level on the move?

Long-term sea level varies at timescales of years, decades and centuries. Before the long-term trend in sea-level rise can be obtained from any sea-level record, we must understand the fluctuations that occur over years and decades. The longest sea-level record in New Zealand is from the Port of Auckland (click to see accompanying figure). The trend in rising sea level at Auckland since 1899 has been 1.4 mm per year (or 0.14 m per century). Larger cycles are evident at periods of two to three decades, which are related to the Pacific-wide climate oscillation called the Interdecadal Pacific Oscillation (IPO). From 1976 to 1998, the IPO was in its positive phase. This same period also coincided with a predominance of El Niño events, which cause sea level to be lower than normal around New Zealand waters. Therefore the sustained period of frequent El Niño events since the late 1970s kept regional mean sea levels down around New Zealand, masking the ongoing global rise in sea level. However, since 1998, the Pacific-wide climate regime has shifted to a negative phase of the IPO, and sea level has risen again. For further information see Sea level on the move? in Water & Atmosphere.

Effect of global warming

The climate is slowly but surely changing towards a warmer world. That means sea level is rising, and will increasingly affect coastal margins (see Sea level on the move?). But global warming will also alter several other drivers that will impact on coastal areas, such as sediment runoff from land, change in wind and wave patterns, altered ocean currents, warmer sea temperatures, and the expectancy of more intense storms. The international body that produces projections of climate change every 5 years is the Intergovernmental Panel on Climate Change or IPCC. The latest 2001 IPCC projections for global change have been combined together with regional knowledge in a publication Planning for Climate Change Effects on Coastal Margins. This publication by the Hazards team for the NZ Climate Change Programme and the Ministry for the Environment summarises the possible impacts on our vulnerable coastal margins and long-term response options that can be built into the planning process.

Educational CD-ROM “New Zealand’s Sandy Coasts”

The team has produced an educational CD called “New Zealand’s Sandy Coasts” as a resource for science and geography teachers. The CD encourages students to learn about coastal processes and will raise awareness of coastal issues and hazards, such as the effect that erosion might have on coastal development. The introductory material includes information on how the CD fits into the New Zealand science, physics and geography curricula. For more information about “New Zealand’s Sandy Coasts” see the announcement in Water & Atmosphere.  Order Form

Coastal & Storm Hazards Workshop

The proceedings of the 2002 Coastal & Storm Hazard Workshop held at the Quality Hotel, Hamilton are now available on-line as a PDF file.