As our average temperature increases, so does the probability of more
extreme weather events.
This means that what we would see as a hot day today is more common into the future with more even hotter extreme events.
Climate projections for Auckland (PDF, 1.22 MB), prepared by
New Zealand’s National Institute of Water and Atmospheric Research (NIWA) , looked at how Auckland’s climate will likely change by 2120.
Temperature changes
The Auckland region is projected to become progressively warmer into the future.
Over the past century, Auckland’s mean annual temperature has increased by about 1.6 degrees Celsius and the impacts of this are already felt across the region.
It is projected to increase further by between 1.5 and 3.75 degrees Celsius by the end of the century, depending on the pace of global emissions reductions.
This means we’re likely to have four times as many ‘hot days’ per year. That is 80 days above 25 degrees Celsius, compared to 20 days currently.
Rainfall changes
Annual total rainfall and seasonal rainfall patterns are likely to change in the Auckland region.
Rainfall in spring is likely to decrease by 15 per cent in some parts of the region. Auckland is projected to be more drought prone, with an increase in the number of dry days.
This will add more than 21 dry days per year by 2110. Drier periods will bring water shortages for residential, agricultural, and industrial use.
Rainfall intensity is projected to increase because a hotter atmosphere can hold more moisture. The intensity of short-duration events is projected to increase by 14 per cent per degree of warming.
This could mean more intense flooding, affecting our
infrastructure, properties, health and safety, as well the local economy.
Marine and coastal changes
The Auckland region is starting to feel the effects of sea level rise. If global emissions stay unchecked, they are projected to rise by a metre by the end of this century.
We also know that melting of glaciers and ice sheet is accelerating, so the change could be even greater. In a region with 3200km of coastline, this means serious threats of
coastal erosion,
storm surges and flooding.
This means that before the end of this century, approximately 1.5 to 2.5 per cent of Auckland’s land area, may be exposed to sea level rise. This covers 0.3 per cent of buildings, 80 per cent of coastal ecosystems and six per cent of dairy land.
Low lying coastal towns and
infrastructure will be more exposed to
coastal inundation / flooding with storm surge.
Marine ecosystems are highly susceptible to climate change.
Ocean acidification will threaten the condition and survival of some marine species.
A rise in ocean temperatures will see species on the move and changes to ecosystems and
moana kai.
Other combined effects
Climate change does not happen in isolation from other changes like population growth, changes in land use, changes to food and energy security, and rising inequality.
In fact, climate change may make many of these challenges even more difficult to solve or may make related impacts on people and communities even more severe. Find out more about the
Impacts on climate change for Māori.
It is also true that our climate change effects are not isolated from other regions and countries. Migration related to climate is already happening across the world. Auckland will need to be part of the solution to support these displaced people.
Many of the implications of climate change will play out through our water systems, whether through too much water in the wrong place (flooding) or too little (drought).
Water and climate change are fundamentally linked and actions to address this cut across our priorities.
