Climate change-driven impacts in New Zealand - from floods to drought and heatwaves - would become more widespread under a 2C warming scenario, compared with 1.5C. Photo / George Heard
The final part of a sweeping stocktake into the state of climate change dropped overnight – finding a critical window to limit global warming to 1.5C is still within our grasp.
But only just.
The latest report of the UN's Intergovernmental Panel on Climate Change (IPCC) - coming a month ahead of New Zealand's first master-plan to cut greenhouse gases (GHGs) - found that, without immediate and deep emissions cuts across every single sector, the world was on track to burst through the 1.5C threshold quickly.
In the past decade, average annual global greenhouse gas emissions were at their highest levels in human history, although the rate of growth has slowed.
The new findings – the final section of the IPCC's Sixth Assessment Report, which has been released in three parts over the past year – showed how crucial the next few years will prove.
In the various scenarios it assessed, limiting warming to around 1.5C required global emissions to peak before 2025 at the latest, and be reduced by 43 per cent by 2030.
At the same time, methane – which makes up a large chunk of New Zealand's greenhouse gas inventory - would also need to be reduced by about a third.
But even if that could be achieved, it was almost inevitable the world would temporarily exceed the 1.5C temperature threshold - but could return to below it by the end of the century.
Earlier, the IPCC warned that some severe impacts could become irreversible if warming passed the 1.5C mark.
And keeping within that bound would still mean that, by the time young children today turned 80, they would've experienced a nearly four-fold increase in extreme events like heatwaves, droughts and floods.
By 2100, the proportion of the world's population exposed to deadly heat stress was also projected to climb from 30 per cent today to somewhere between 48 and 76 per cent.
As many as three billion people could experience chronic water scarcity from droughts if warming reached 2C – and up to four billion under 4C of global temperature rise – with grim consequences for food production and ecosystems.
New Zealand could expect much more of what climate change has already brought us: more hot days, fewer cold days, melting glaciers, rising snowlines, heavier deluges and gradually acidifying oceans.
Northern regions of our country would suffer more droughts and extreme fire danger, it found, while, on our southeastern coasts, effects like ocean warming and marine heatwaves could kill off kelp forests.
"It's now or never, if we want to limit global warming to 1.5C," said Jim Skea, co-chair of the latest report, and a professor of sustainable energy at the UK's Imperial College London.
"Without immediate and deep emissions reductions across all sectors, it will be impossible."
The global temperature would only stabilise when carbon dioxide emissions reach net zero.
For 1.5C, that meant achieving net zero carbon dioxide emissions globally in the early 2050s; for 2C – the bottom line of the landmark Paris Agreement that New Zealand and around 200 nations have signed up to - it was in the early 2070s.
This assessment showed that limiting warming to around 2C still required global greenhouse gas emissions to peak before 2025 at the latest - and be reduced by a quarter by 2030.
The report noted that 83 per cent of net growth in greenhouse gases since 2010 has occurred in Asia and the Pacific – and that New Zealand, Australia and Japan, as a group, had some of the highest rates of GHG emissions per capita in 2019.
In New Zealand alone, emissions have shot up by more than a quarter in the past three decades – with much of that increase coming from methane belched by dairy cattle and CO2 from road transport.
"The latest insights from the IPCC are clear and the case for action couldn't be any stronger or more urgent," Climate Change Minister James Shaw said.
"As a country that relies on our environment for so much, addressing climate change isn't a nice to have, it's essential."
“It’s now or never, if we want to limit global warming to 1.5°C (2.7°F).” – #IPCC Working Group III Co-Chair Jim Skea on the release of IPCC’s latest #ClimateReport on the mitigation of #climatechange.
— IPCC (@IPCC_CH) April 4, 2022
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Last year, New Zealand's independent Climate Change Commission found the country's current climate policies failed to reflect what was needed to keep within 1.5C.
As at 2021, New Zealand was on track to undershoot our set 2050 target of net-zero long-lived gases by some 6.3 million tonnes of carbon dioxide equivalent – and that we couldn't keep planting our way out of tough action.
The commission recommended a wholesale transformation across virtually every corner of the economy – from the cars we drive and import, and the cows and sheep we farm, through to the energy we produce and consume, the forests we plant and the houses we build.
Moreover, it set out a radical transition that, while changing the face of our country forever, would largely all happen within the next 15 years.
Cabinet ministers have since been assessing how those recommendations would fit into the Government's Emissions Reduction Plan, which would lock in three five-year carbon budgets, and was due to be published next month, after a lengthy delay.
"The challenge ahead may feel daunting, but the report also highlights a number of effective and innovative ways we can lower emissions and limit the effects of climate change," Shaw said.
"And that is exactly what our Emissions Reduction Plan will do at a national level.
"Our climate targets are not optional, they are critical – the Emissions Reduction Plan will set out how we are going to achieve them, and what we must all do to make it happen."
While the plan will go out for consultation on release, some measures - like a "feebate" targeting high-emitting vehicles - have already been advanced.
Globally, the UN report found that, since 2010, there have been sustained decreases of up to 85 per cent in the costs of solar and wind energy, and batteries.
An increasing range of policies and laws have enhanced energy efficiency, reduced rates of deforestation and accelerated the deployment of renewable energy.
"We are at a crossroads," IPCC chair Hoesung Lee said.
"The decisions we make now can secure a liveable future. We have the tools and know-how required to limit warming."
"I am encouraged by climate action being taken in many countries. There are policies, regulations and market instruments that are proving effective.
"If these are scaled up and applied more widely and equitably, they can support deep emissions reductions and stimulate innovation."
There were options in all sectors to at least halve emissions by the turn of the next decade.
Limiting global warming would require major transitions in the energy sector – and involve substantial reduction in fossil fuel use, widespread electrification, improved energy efficiency, and use of alternative fuels, such as hydrogen, which New Zealand has been exploring.
"Having the right policies, infrastructure and technology in place to enable changes to our lifestyles and behaviour can result in a 40 to 70 per cent reduction in greenhouse gas emissions by 2050," IPCC Working Group III co-chair Priyadarshi Shukla said.
"This offers significant untapped potential. The evidence also shows that these lifestyle changes can improve our health and wellbeing."
Cities and other urban areas also offer significant opportunities for emissions reductions.
These can be achieved through lower energy consumption - such as by creating compact, walkable cities – along with electrification of transport in combination with low-emission energy sources, and enhanced carbon uptake and storage using nature.
There are options for established, rapidly growing and new cities.
"We see examples of zero energy or zero-carbon buildings in almost all climates," Skea said.
"Action in this decade is critical to capture the mitigation potential of buildings."
In the energy sector, achieving net zero would require new production processes, low and zero emissions electricity, hydrogen, and, where necessary, carbon capture and storage, the report found.
Agriculture, forestry, and other land use could provide large-scale emissions reductions - and also remove and store carbon dioxide at scale.
On climate finance, the report found financial flows were still a factor of three to six times lower than levels needed by 2030 to limit warming to below 2C.
While there was enough global capital and liquidity to close investment gaps, this relied on clear signalling from governments and the international community - including a stronger alignment of public sector finance and policy.
"Without taking into account the economic benefits of reduced adaptation costs or avoided climate impacts, global GDP would be just a few percentage points lower in 2050 if we take the actions necessary to limit warming to 2C or below, compared to maintaining current policies," Shukla said.
And importantly, accelerated and equitable climate action in adapting to climate change impacts was critical to sustainable development.
Some response options could absorb and store carbon and, at the same time, help communities limit the impacts associated with climate change.
In cities, networks of parks and open spaces, wetlands and urban agriculture could reduce flood risk and reduce heat-island effects.
Targeted climate mitigation in industries could reduce environmental impacts, while also growing business. Electrification with renewables and shifts in public transport could boost health, employment, and equity.
"Climate change is the result of more than a century of unsustainable energy and land use, lifestyles and patterns of consumption and production," Skea said.
"This report shows how taking action now can move us towards a fairer, more sustainable world."
Firefighters responded shortly before 9am on Friday.