Climate change projections for the Gisborne and Hawke's Bay region

Map of Gisborne and Hawke's Bay regions.

This page provides an overview of how the climate in the Gisborne and Hawke's Bay regions is likely to change in the future and what implications this has for the region.

Projections of climate change depend on future greenhouse gas emissions, which are uncertain. There are four main global emissions scenarios ranging from low to high greenhouse gas concentrations. This page presents regional projections as a range of values from a low emissions to a high emissions future.

The projected changes are calculated for 2031–2050 (referred to as 2040) and 2081–2100 (2090) compared to the climate of 1986–2005 (1995).

Temperature

Compared to 1995, temperatures are likely to be 0.7˚C to 1.1˚C warmer by 2040 and 0.7˚C to 3.1˚C warmer by 2090.

By 2090, Gisborne and the Hawke’s Bay are projected to have from 8 to 51 extra days per year where maximum temperatures exceed 25˚C. Frosts are likely to become rare in Gisborne, and the number of frosts could decrease by up to 15 days per year in the Hawke’s Bay by 2090.

Rainfall

Rainfall will vary locally within the region. The largest changes will be for particular seasons rather than annually.

Winter rainfall is projected to decrease by 2 to 13 per cent in Gisborne and 2 to 17 per cent in Napier by 2090. Spring rainfall is projected to decrease by 3 to 15 per cent in Gisborne and 2 to 13 per cent in Napier by 2090. However summer and autumn rainfall are both expected to increase.

According to the most recent projections, the Gisborne and Hawke’s Bay regions are not expected to experience a significant change in the frequency of extreme rainy days as a result of climate change. 

Wind

The frequency of extremely windy days in Gisborne and Hawke’s Bay by 2090 is not likely to change significantly. There may be an increase in westerly wind flow during winter and north-easterly wind flow during summer.

Storms

Future changes in the frequency of storms are likely to be small compared to natural inter-annual variability. Some increase in storm intensity, local wind extremes and thunderstorms is likely to occur.

The frequency of ex-tropical cyclones is projected to either decrease or remain unchanged over the 21st century; however they are likely be stronger and cause more damage as a result of heavy rain and strong winds. 

Sea-level rise

New Zealand tide records show an average rise in relative mean sea level of 1.7 mm per year over the 20th century. Globally, the rate of rise has increased, and further rise is expected in the future.

The Ministry for the Environment provides guidance on coastal hazards and climate change, including recommendations for sea level rise, see Preparing for coastal change: A guide for local government in New Zealand.  An updated edition will be published in late 2016.

Impacts by season

By 2090, the region could expect*:

Spring

  • 0.7°C to 2.8°C temperature rise in Gisborne and Hawke’s Bay
  • 3 to 15 per cent less rainfall in Gisborne
  • 2 to 13 per cent less rainfall in Napier

Summer

  • 0.7°C to 3.2°C temperature rise in Gisborne
  • 0.7°C to 3.1°C temperature rise in Hawke’s Bay
  • 2 per cent less to 11 per cent more rainfall in Gisborne
  • 4 per cent less to 16 per cent more rainfall in Napier

Autumn

  • 0.7°C to 3.2°C temperature rise in Gisborne
  • 0.7°C to 3.1°C temperature rise in Hawke’s Bay
  • No change to 5 per cent more rainfall in Gisborne
  • 1 to 7 per cent more rainfall in Napier 

Winter

  • 0.7°C to 3.1°C temperature rise in Gisborne and Hawke’s Bay
  • 2 to 13 per cent less rainfall in Gisborne
  • 2 to 17 per less rainfall in Napier

*Projected changes are relative to 1995 levels. The values provided capture the range across all scenarios. They are based on scenario estimates and should not be taken as definitive. For more information, see the full report on climate projections.

What could this mean for Gisborne and the Hawke's Bay by 2090?

Drought – By 2090, the time spent in drought for Gisborne and the Hawke’s Bay ranges from minimal change through to more than double compared to 1995, depending on the climate model and emissions scenario considered. More frequent droughts are likely to lead to water shortages, increased demand for irrigation and increased risk of wild fires. Droughts are likely to increase in both intensity and duration.

Coastal hazards – There may be increased risk to coastal roads and infrastructure from coastal erosion and inundation, increased storminess and sea-level rise. Sea-level rise is likely to result in more coastal floods.

Erosion – Drier average conditions potentially combined with more intense rainfall at times, could lead to increased problems with erosion and flooding.

Disease – There may be an increase in the occurrence of summer water-borne and food-borne diseases such as Salmonella. There could also be an increased risk from some vector-borne diseases such as Dengue Fever and Ross River Virus.

Biosecurity – Climate change could lead to changes in pests and diseases with a likely increase in weed species and subtropical pests and diseases invading over time. This may require new pest management approaches.

Agriculture – Warmer temperatures, a longer growing season and fewer frosts could provide opportunities to grow new crops. Farmers might benefit from faster growth of pasture and better crop growing conditions. However, these benefits may be limited by negative effects of climate change such as prolonged drought or greater frequency and intensity of storms. Some crops may no longer be economic in the Gisborne region. There will be increasing pressure on water resources.

The Ministry for Primary Industries website and associated Climate Cloud website have more information on the regional impacts of climate change on agriculture.

Find out more

Gisborne District Council’s climate change information [Gisborne District Council website]

Hawke’s Bay Regional Council’s climate change information [Hawke's Bay Regional Council website]

Reviewed:
30/06/16