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How might climate change affect my region? Climate change in Wellington, Kapiti and Wairarapa

Wellington and Kapiti are often windy because of their exposure to disturbed weather systems from the Tasman Sea and the Cook Strait, but apart from this they have relatively few climate extremes with warm summers and coolish winters. The Wairarapa region enjoys predominantly warm dry settled weather in summer and relatively mild winters.

A change in our climate as a result of global warming and other influences means we need to think about how we are going to plan for and manage the projected impacts of climate change in Wellington, the Kapiti coast, Wairarapa and New Zealand. But we also need to take appropriate action to reduce our share of greenhouse gas emissions responsible for global warming and climate change impacts.

Some of the predicted impacts of a moderate rate of climate change for Wellington, the Kapiti coast and Wairarapa include changes in average temperature, sea level rise and rainfall patterns. In general, the region will be warmer and the west of the region, like much of the west coast of New Zealand, is likely to become wetter.

Climate scientists estimate that temperatures in Wellington, the Kapiti coast and Wairarapa could be up to 3°C warmer over the next 70-100 years. This compares to a temperature increase in New Zealand during last century of about 0.7°C. To put this in perspective, the 1997/98 summer, which many New Zealanders remember as particularly long, hot and dry, was only about 0.9°C above New Zealand's average for the 1990s.

The west of the region could be up to 20% wetter while eastern areas could be up to 20% drier. The region as a whole is likely to experience more varied rainfall patterns and flooding could become up to four times as frequent by 2070.

The effects of climate change may bring significant costs to the community.

If extreme weather events become more frequent or severe, the costs and damages associated with them are also likely to increase. The cost of dealing with stock losses, replacing or repairing damaged roads, bridges, houses and stormwater drains, and dealing with increased soil erosion and loss of soil nutrients can be formidable. Recent extreme weather events such as the Marlborough and Canterbury droughts, Cyclone Bola, the "weather bomb" in the Waikato/Coromandel area, and coastal flooding during the Waitangi Day storm, have shown how vulnerable our society and economy is to the weather and climate.

There are likely to be benefits and opportunities from a change in climate too. Farmers in the west could benefit from better crop growing conditions and faster growth of pasture but greater fertiliser use would probably be needed. There could also be opportunities to grow new crops, with a longer growing season and fewer frosts. Wine grapes in the Wairarapa particularly could benefit from warmer, drier conditions.

However, if the rate and magnitude of climate change is not slowed down, that is, if we don't reduce greenhouse gas emissions, any beneficial effects of climate change are expected to diminish and the adverse effects and long-term risks expected to increase.

The climate in Wellington and Kapiti

Because of its exposure to disturbed weather systems from the Tasman Sea and the Cook Strait, this region is often quite windy, but apart from this has relatively few climate extremes. The most settled weather occurs during summer and early autumn. Summers are warm. Typical summer daytime maximum air temperatures range from 19°C to 24°C, seldom exceeding 30°C. Winters are fairly cool and this is normally the most unsettled time of the year. Typical winter daytime maximum air temperatures range from 10°C to 14°C. Annual sunshine hours average about 2000 hours. Northwesterly airflows prevail.

Wairarapa's climate

Sheltered by high country to the west, this region enjoys a dry, sunny climate. Warm dry settled weather predominates in summer. Frosts may occur in winter. Typical summer daytime maximum air temperatures range from 20°C to 28°C, occasionally rising above 30°C. High temperatures are frequent in summer, which may be accompanied by strong dry foehn winds from the northwest. Winter is relatively mild with typical daytime maximum air temperatures ranging from 10°C to 16°C. Heavy rainfall can occur from the east. Westerly winds prevail. Sea breezes often occur in coastal areas on warm summer days.

Last updated: 20 March 2008