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How might climate change affect my region? Climate Change in Manawatu-Wanganui

The Manawatu-Wanganui region is often quite windy because of its exposure to disturbed weather systems from the Tasman Sea, but it has relatively few climate extremes with warm summers and reasonably 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 Manawatu-Wanganui 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 Manawatu-Wanganui include changes in average temperature, sea level rise and rainfall patterns. In general, Manawatu-Wanganui, like much of the west coast of New Zealand, is likely to become warmer and wetter.

Climate scientists estimate that temperatures in Manawatu-Wanganui 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.

Manawatu-Wanganui could be up to 20% wetter with 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 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.

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 the Manawatu-Wanganui region

Because of its exposure to disturbed weather systems from the Tasman Sea, this region is often quite windy, but 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 relatively mild in Wanganui, but cooler in Palmerston North. This is normally the most unsettled time of the year. Typical winter daytime maximum air temperatures range from 10°C to 14°C. Frost occurs inland during clear calm conditions in winter. Annual sunshine hours average about 2000 hours, but inland at Palmerston North it is much cloudier. Northwesterly airflows prevail. Sea breezes occasionally occur along the coast during summer.

Last updated: 20 March 2008