Figure 6.9.5 Future return periods (years) of current climate 1-in-20 year PED events, for four scenarios: CSIRO 2030s 25% and 75% scaling (upper panels) and Hadley 2030s 25% and 75% scaling (lower panels)
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This is the equivalent of Figure 3.4, but for the 2030s instead of the 2080s.
Text description of figure
This figure is similar to Figure 3.4 except that future return periods are presented for the 2030s scenarios.
The figure consists of four maps indicating how the frequency of what is currently a 1-in-20 year drought may change by the 2030s, for two different climate models (CSIRO, top, and Hadley, bottom), and for two different greenhouse gas emission scalings (25%, left, and 75%, right). The smallest changes are seen under the CSIRO model and 25% emission scaling, and the biggest changes under the Hadley model and 75% emission scaling.
The top left map applies to the CSIRO model and 25% emission scaling. It indicates that what is currently a 1-in-20 year drought could become a 1-in-5 to 1-in-10 year drought in Northland, Coromandel, and in parts of Waikato, Bay of Plenty, Buller, south-east Southland and Stewart Island. The western and southern regions are quite wet under the current climate, so the term "drought" is a relative term.
The top right map applies to the CSIRO model and 75% emission scaling. It indicates that what is currently a 1-in-20 year drought could become a 1-in-5 to 1-in-10 year drought in the northern regions from Northland to East Cape, Taranaki, Wanganui, Buller, Southland and Stewart Island. The largest increase in drought risk, from the current 1-in-20 years to every 3 to 5 years, occurs in Northland near Whangarei. Other parts of the country would see a lesser or no change in drought risk.
The bottom left map applies to the Hadley model and 25% emission scaling. It indicates that what is currently a 1-in-20 year drought could become a 1-in-5 to 1-in-10 year drought in the southern part of Northland, the Coromandel, Bay of Plenty, East Cape, Hawke’s Bay, most parts of the Wairarapa, and from eastern Marlborough down to Otago. The largest increase in drought risk, from the current 1-in-20 years to every 3 to 5 years, occurs in Hawkes Bay near Tutira. Other parts of the country would see a lesser or no change in drought risk.
The bottom right map applies to the Hadley model and 75% emission scaling. It indicates that what is currently a 1-in-20 year drought could occur every 3 to 5 years on Great Barrier Island and in Gisborne, Hawke’s Bay, Kaikoura and in scattered regions around Whangarei, Tauranga, Waipukurau, south Canterbury and North Otago. In Northland, greater Auckland, Coromandel, Bay of Plenty, East Cape, Wairarapa, Nelson, Marlborough, Canterbury and North Otago, the current 1-in-20 year drought could become a 1-in-5 to 1-in-10 year drought. Other parts of the country would see a lesser or no change in drought risk.
