Global and national efforts to reduce greenhouse gas emissions must continue or Tairāwhiti heatwaves could more than double annually.
The warning has come from Dr Andrew Tait, of the National Institute of Water and Atmospheric Research (Niwa).
During an online Niwa presentation last month, Dr Tait talked through climate projections which showed that Tairāwhiti is forecast to experience more extreme weather events, including the possibilities of droughts, wildfires, and flooding, especially in the latter half of the century.
However, there was a lot we could do to slow down and reduce greenhouse gas emissions, he told LDR.
To form these climate projections, Dr Tait said scientists used complex, physics-based computer models to calculate different climate outcomes with differing levels of greenhouse gases.
“These projections are not crystal balls, but they can provide us with useful information about what the future climate could look like,” Dr Tait said during his presentation.
Tairāwhiti was projected to become drier, while other areas of New Zealand - like the West Coast of the South Island - were likely to become wetter, he said.
“We’re also expected to experience more extreme events, like flooding.”
The driving reason behind the increase in flooding was that the warmer the atmosphere, the more water the atmosphere was able to hold - which could lead to more water being released as heavy rainfall during storms, he said.
Dr Tait told LDR there were some greenhouse gas scenarios which would see steep increases in global warming and extreme weather events, whereas in other scenarios, there were more hopeful pathways.
“There are scenarios where the greenhouse gas concentrations level off and stay even - and that leads to very moderate changes in temperature and rainfall,” he said.
Dr Tait said during his presentation that some climate model scenarios showed that:
•By the year 2090 it is predicted that Tairāwhiti’s wildfire risk could increase by 30-40 per cent;
•Currently Gisborne has around 25 annual heatwave days, and six to eight heat stress days (which are hot, humid days that affect human and animal health). By the end of the century, we could get up to 20-60 more heatwave days annually, and between eight to16 heat stress days annually, depending on greenhouse gas emissions;
•For every degree of warming, it is projected that one-hour heavy rainfalls could increase by 12-14 per cent.
The driving force behind these climate changes is emissions of greenhouse gases such as carbon dioxide, which is produced through burning coal and oil.
The “business as usual” of greenhouse gas emissions has changed since the Paris Agreement, Dr Tait told LDR.
“We have seen a lot of work around the world and in NZ to reduce emissions. If we keep on this path of continuing to work together as a global community, then we may be on one of the middle to lower emission scenarios.
“That would mean that there would still be increases with things like drought intensity, but far less severe than if we were in a very high emissions scenario.”
However: “Even with the Paris accord goals, we need to do more”, he said.
The Paris Agreement is an international treaty which aims to keep global warming levels to well below 2 degrees above pre-industrial levels by the end of the century.
“We’re already hitting one and a half degrees on a monthly basis,” Dr Tait said.
Under the Paris Agreement, every country sets a nationally determined contribution (NDC).
NZ updated its NDC in October 2021, aiming to reduce net emissions by 50 per cent below gross 2005 level by the year 2030.
Dr Tait said that every region and city in NZ had a plan for reducing their carbon footprints and nationally, NZ had an even greater focus on using 100 per cent renewable energies.
Gisborne District Council’s Climate Change Road Map to 2050 shows that the council aims to become a zero-carbon organisation by 2050.
GDC aims to work with Treaty partners and other stakeholders to achieve regional decarbonisation, and ensure that the region’s economy is protected from the impacts of climate change - as well as ensure that risks are reduced and Tairāwhiti is resilient to further change.
Additionally, GDC plans show that between 2022-2023, it will continue “existing adaptation actions such as flood mitigation and Waingake planting”.
LDR has approached the council for comment on the progress of the Climate Change Road Map.
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LDR is local body journalism co-funded by RNZ and NZ On Air.
