Climate Advocates Discuss the IPCC 6th Assessment Report’s Impact on NZ

The IPPC’s 6th Assessment Report has confirmed that human activities have caused climate change. What climate scientists have warned us repeatedly about is now materialising before our eyes. Climate change is here and will keep getting worse.

The Working Group 1 contribution to the Sixth Assessment Report (AR6), Climate Change 2021: The Physical Science Basis, is considered a landmark report and the first scientific review since the IPCC released the 5th Assessment Report in 2013.

Under all emissions scenarios, the earth’s surface temperature will increase by 1.5°C to 1.6°C in the next twenty years. We are on track to exceed the 1.5°C limit by 2040, and this rapid warming is unprecedented and hasn’t been seen in hundreds or thousands of years.

Warming will make extreme events more frequent and intense, and changes like sea-level rise are irreversible and will go on for up to a thousand years.

Though very sobering, the report provides some hope. Limiting climate change would only be possible through strong and sustained emissions reductions of carbon dioxide and other greenhouse gases.

The speed of transition will make a difference, preventing every ton of emissions from going to the atmosphere, averting a tenth of a degree of warming, and lessening the impact of climate for centuries.

While drastic emissions reductions will clear the air, the IPCC Working Group 1 report estimates that stabilising global temperatures will take 20-30 years (IPCC, 2021).

The almost 4,000-page document contains about 14,000 scientific reports that present the most up-to-date understanding of the climate system and climate change, gathered from multiple evidence- paleoclimate, observations, process understanding, and global and regional climate simulations.

But what does this report mean for New Zealand’s climate, and what are its implications for the country?

Talking about what’s in store for their country, Satherly’s article mentions the following:

• Since records began, New Zealand’s mean temperature has increased to 1.1°C (on page 3522 of the report).

With 2 degrees of warming, there will be:

• “Decreases in snow and ice or increases in pluvial/river flooding will affect sectors such as winter tourism, energy production, river transportation, and infrastructure” (page 132).
• “Fire weather is projected to increase throughout Australia and New Zealand” (page 136).
• “Fire weather is projected to increase throughout Australia and New Zealand. Snowfall is expected to decrease throughout the region at high altitudes in Australia and New Zealand, with glaciers receding in New Zealand.”
• Wellington and Dunedin will be far more at risk of fires (page 3197).
• The south and west of the country will get wetter, and the north and east will dry up (page 3197).
• As the planet warms, storms will move towards the poles in many regions, particularly in the southern hemisphere.
• High-pressure regions in the subtropics are expanding poleward. In New Zealand, this will increase precipitation in the west and south during winter and spring, while the north and east will see reductions in rainfall.

What if the temperature increase exceeds 3°C?

Suppose temperatures rise to over 3°C. In that case, all glaciers will melt in New Zealand (page 2160), along with three quarters around the world, there will be 39 to 50 per cent fewer “frost days” (page 3194), “Agricultural and ecological” droughts will be more common (page 3196), landslides will be more likely in the South Island and eastern half of the North Island due to “total precipitation rates, precipitation intensity, mountain permafrost thaw rates, glacier retreat and air temperature” (page 3195). There will be a “continuing reduction in snowfall during the 21st century” (page 3198). 

From 2030, areas below 1500m will likely go without snow for years.

“As mean sea-level rise is projected to continue for at least several more centuries, there is very high confidence that this will lead to large increases in the frequency of extreme sea-level events in Australia and New Zealand” (page 3518). 

The News Hub article says scientists fear that if we don’t drastically reduce emissions in the next 20 years, we will cross the dangerous threshold of 1.5°C of warming.

New Zealand cities will be more vulnerable because they host 90 per cent of the population. Given these stark climate projections, the government’s reduction plan will become crucial to deliver results.

Nick Cradock-Henry, a scientist at Landcare Research, says that drought will become the nation’s most costly threat. This threat will have further social and economic implications for rural communities and will require farmers to adapt and cut their emissions (Satherly, 2021). 

He says that mitigation alone will not be sufficient to address the climate crises; instead, climate adaptation will be needed. “Adaptation will require strategic and even radical adjustments to practices, processes, capital, and infrastructure in response to climate change, and must begin now,” he adds.

Lauren Vargo, a research fellow at Victoria University’s Antarctic Research Centre, said that climate changes in New Zealand would impact water resources, hydropower, and tourism, and increases in ocean warming will impact the country’s seafood resources.

Click the links below to read the IPCC report:

A 2-page regional fact sheet that summarises climate observations and projections in the Australasia region.