Within the same period, sea level was expected to rise between 50cm and 120cm, leaving populations to adapt by either abandoning coasts and islands, changing infrastructure and coastal zones, or protecting areas with barriers or dykes.
Already, temperatures in Auckland had warmed by 1C over the last 100 years, while sea level rise from 1899 to 2014 was in the order of 18 cm, Dr Salinger said.
A report on sea level rise by Parliamentary Commissioner for the Environment Dr Jan Wright said the impact of even a small rise in sea level would be significant and very costly for some landowners.
Storms occurring on top of a higher sea level would affect public infrastructure such as roads, railways and stormwater systems, as well as private homes and other buildings.
Climate change was also expected to result in more large storms compounding the effects of sea level rise.
The major coastal floods that Auckland experienced in 1936 and 2011 -- the latter flooding downtown shops, homes and roads -- would occur about once every decade, according to Niwa projections.
If climate change continued unabated, that frequency could increase to each year.
"Just think about what happened in April this year, where there was flooding on the northwestern motorway and Tamaki Drive. That would become commonplace," Dr Salinger said.
"We really have to be thinking now about how we plan cities -- including where people are and what they'll need to do -- because these sorts of things take a while to implement."
In another impact Dr Salinger will address, Auckland would feel the effect of climate change on Pacific nations, which he considered New Zealand's "front yard".
He said the risk of displacement and relocation from Pacific islands was a reality, and building capacity for an influx of new residents in Auckland now should be a priority.
Auckland Pacific communities would also need to be strong to accommodate migrants and assist those remaining in the islands.
Dr Salinger noted how New Zealand's 20,000-strong Niuean population, mainly in Auckland, raised funds and provided volunteers to help in Niue in the wake of the devastating Cyclone Heta in 2004.
Industries would also see change.
Hayward kiwifruit production may become uneconomic in Auckland over the next 50 years, due to a lack of winter chilling, while sub-tropical crops such as avocados and citrus would benefit from a trend towards warmer average conditions.
Some tropical fruit crops could presently be grown in localised micro-climates in Auckland, but it was likely that opportunities for these crops would increase, he said.
A warmer climate might change where wine production could be based around the region, but would also bring more pest and disease pressure.
Rising ocean temperatures and ocean acidification was also altering marine life, moving fisheries southward, threatening shell fisheries, and changing life cycles.
But Dr Salinger said climate warming was just one of several pressures on fisheries, and reducing fishing pressure could only help the situation.
His talk, part of the Auckland Conservations series, will be held from 5.30pm tomorrow, December 4, at the Sir Paul Reeves Building lecture theatre, Governor Fitzroy Pl.
